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postgres/src/backend/utils/cache/relcache.c
Tom Lane 9fa6f00b13 Rethink MemoryContext creation to improve performance. 
This patch makes a number of interrelated changes to reduce the overhead
involved in creating/deleting memory contexts.  The key ideas are:

* Include the AllocSetContext header of an aset.c context in its first
malloc request, rather than allocating it separately in TopMemoryContext.
This means that we now always create an initial or "keeper" block in an
aset, even if it never receives any allocation requests.

* Create freelists in which we can save and recycle recently-destroyed
asets (this idea is due to Robert Haas).

* In the common case where the name of a context is a constant string,
just store a pointer to it in the context header, rather than copying
the string.

The first change eliminates a palloc/pfree cycle per context, and
also avoids bloat in TopMemoryContext, at the price that creating
a context now involves a malloc/free cycle even if the context never
receives any allocations.  That would be a loser for some common
usage patterns, but recycling short-lived contexts via the freelist
eliminates that pain.

Avoiding copying constant strings not only saves strlen() and strcpy()
overhead, but is an essential part of the freelist optimization because
it makes the context header size constant.  Currently we make no
attempt to use the freelist for contexts with non-constant names.
(Perhaps someday we'll need to think harder about that, but in current
usage, most contexts with custom names are long-lived anyway.)

The freelist management in this initial commit is pretty simplistic,
and we might want to refine it later --- but in common workloads that
will never matter because the freelists will never get full anyway.

To create a context with a non-constant name, one is now required to
call AllocSetContextCreateExtended and specify the MEMCONTEXT_COPY_NAME
option.  AllocSetContextCreate becomes a wrapper macro, and it includes
a test that will complain about non-string-literal context name
parameters on gcc and similar compilers.

An unfortunate side effect of making AllocSetContextCreate a macro is
that one is now *required* to use the size parameter abstraction macros
(ALLOCSET_DEFAULT_SIZES and friends) with it; the pre-9.6 habit of
writing out individual size parameters no longer works unless you
switch to AllocSetContextCreateExtended.

Internally to the memory-context-related modules, the context creation
APIs are simplified, removing the rather baroque original design whereby
a context-type module called mcxt.c which then called back into the
context-type module.  That saved a bit of code duplication, but not much,
and it prevented context-type modules from exercising control over the
allocation of context headers.

In passing, I converted the test-and-elog validation of aset size
parameters into Asserts to save a few more cycles.  The original thought
was that callers might compute size parameters on the fly, but in practice
nobody does that, so it's useless to expend cycles on checking those
numbers in production builds.

Also, mark the memory context method-pointer structs "const",
just for cleanliness.

Discussion: https://postgr.es/m/2264.1512870796@sss.pgh.pa.us
2017-12-13 13:55:16 -05:00

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/*-------------------------------------------------------------------------
*
* relcache.c
* POSTGRES relation descriptor cache code
*
* Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/utils/cache/relcache.c
*
*-------------------------------------------------------------------------
*/
/*
* INTERFACE ROUTINES
* RelationCacheInitialize - initialize relcache (to empty)
* RelationCacheInitializePhase2 - initialize shared-catalog entries
* RelationCacheInitializePhase3 - finish initializing relcache
* RelationIdGetRelation - get a reldesc by relation id
* RelationClose - close an open relation
*
* NOTES
* The following code contains many undocumented hacks. Please be
* careful....
*/
#include "postgres.h"
#include <sys/file.h>
#include <fcntl.h>
#include <unistd.h>
#include "access/hash.h"
#include "access/htup_details.h"
#include "access/multixact.h"
#include "access/nbtree.h"
#include "access/reloptions.h"
#include "access/sysattr.h"
#include "access/xact.h"
#include "access/xlog.h"
#include "catalog/catalog.h"
#include "catalog/index.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/partition.h"
#include "catalog/pg_am.h"
#include "catalog/pg_amproc.h"
#include "catalog/pg_attrdef.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_auth_members.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_database.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_partitioned_table.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_publication.h"
#include "catalog/pg_rewrite.h"
#include "catalog/pg_shseclabel.h"
#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_subscription.h"
#include "catalog/pg_tablespace.h"
#include "catalog/pg_trigger.h"
#include "catalog/pg_type.h"
#include "catalog/schemapg.h"
#include "catalog/storage.h"
#include "commands/policy.h"
#include "commands/trigger.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/prep.h"
#include "optimizer/var.h"
#include "rewrite/rewriteDefine.h"
#include "rewrite/rowsecurity.h"
#include "storage/lmgr.h"
#include "storage/smgr.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/relmapper.h"
#include "utils/resowner_private.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"
#include "utils/tqual.h"
#define RELCACHE_INIT_FILEMAGIC 0x573266 /* version ID value */
/*
* hardcoded tuple descriptors, contents generated by genbki.pl
*/
static const FormData_pg_attribute Desc_pg_class[Natts_pg_class] = {Schema_pg_class};
static const FormData_pg_attribute Desc_pg_attribute[Natts_pg_attribute] = {Schema_pg_attribute};
static const FormData_pg_attribute Desc_pg_proc[Natts_pg_proc] = {Schema_pg_proc};
static const FormData_pg_attribute Desc_pg_type[Natts_pg_type] = {Schema_pg_type};
static const FormData_pg_attribute Desc_pg_database[Natts_pg_database] = {Schema_pg_database};
static const FormData_pg_attribute Desc_pg_authid[Natts_pg_authid] = {Schema_pg_authid};
static const FormData_pg_attribute Desc_pg_auth_members[Natts_pg_auth_members] = {Schema_pg_auth_members};
static const FormData_pg_attribute Desc_pg_index[Natts_pg_index] = {Schema_pg_index};
static const FormData_pg_attribute Desc_pg_shseclabel[Natts_pg_shseclabel] = {Schema_pg_shseclabel};
static const FormData_pg_attribute Desc_pg_subscription[Natts_pg_subscription] = {Schema_pg_subscription};
/*
* Hash tables that index the relation cache
*
* We used to index the cache by both name and OID, but now there
* is only an index by OID.
*/
typedef struct relidcacheent
{
Oid reloid;
Relation reldesc;
} RelIdCacheEnt;
static HTAB *RelationIdCache;
/*
* This flag is false until we have prepared the critical relcache entries
* that are needed to do indexscans on the tables read by relcache building.
*/
bool criticalRelcachesBuilt = false;
/*
* This flag is false until we have prepared the critical relcache entries
* for shared catalogs (which are the tables needed for login).
*/
bool criticalSharedRelcachesBuilt = false;
/*
* This counter counts relcache inval events received since backend startup
* (but only for rels that are actually in cache). Presently, we use it only
* to detect whether data about to be written by write_relcache_init_file()
* might already be obsolete.
*/
static long relcacheInvalsReceived = 0L;
/*
* eoxact_list[] stores the OIDs of relations that (might) need AtEOXact
* cleanup work. This list intentionally has limited size; if it overflows,
* we fall back to scanning the whole hashtable. There is no value in a very
* large list because (1) at some point, a hash_seq_search scan is faster than
* retail lookups, and (2) the value of this is to reduce EOXact work for
* short transactions, which can't have dirtied all that many tables anyway.
* EOXactListAdd() does not bother to prevent duplicate list entries, so the
* cleanup processing must be idempotent.
*/
#define MAX_EOXACT_LIST 32
static Oid eoxact_list[MAX_EOXACT_LIST];
static int eoxact_list_len = 0;
static bool eoxact_list_overflowed = false;
#define EOXactListAdd(rel) \
do { \
if (eoxact_list_len < MAX_EOXACT_LIST) \
eoxact_list[eoxact_list_len++] = (rel)->rd_id; \
else \
eoxact_list_overflowed = true; \
} while (0)
/*
* EOXactTupleDescArray stores TupleDescs that (might) need AtEOXact
* cleanup work. The array expands as needed; there is no hashtable because
* we don't need to access individual items except at EOXact.
*/
static TupleDesc *EOXactTupleDescArray;
static int NextEOXactTupleDescNum = 0;
static int EOXactTupleDescArrayLen = 0;
/*
* macros to manipulate the lookup hashtable
*/
#define RelationCacheInsert(RELATION, replace_allowed) \
do { \
RelIdCacheEnt *hentry; bool found; \
hentry = (RelIdCacheEnt *) hash_search(RelationIdCache, \
(void *) &((RELATION)->rd_id), \
HASH_ENTER, &found); \
if (found) \
{ \
/* see comments in RelationBuildDesc and RelationBuildLocalRelation */ \
Relation _old_rel = hentry->reldesc; \
Assert(replace_allowed); \
hentry->reldesc = (RELATION); \
if (RelationHasReferenceCountZero(_old_rel)) \
RelationDestroyRelation(_old_rel, false); \
else if (!IsBootstrapProcessingMode()) \
elog(WARNING, "leaking still-referenced relcache entry for \"%s\"", \
RelationGetRelationName(_old_rel)); \
} \
else \
hentry->reldesc = (RELATION); \
} while(0)
#define RelationIdCacheLookup(ID, RELATION) \
do { \
RelIdCacheEnt *hentry; \
hentry = (RelIdCacheEnt *) hash_search(RelationIdCache, \
(void *) &(ID), \
HASH_FIND, NULL); \
if (hentry) \
RELATION = hentry->reldesc; \
else \
RELATION = NULL; \
} while(0)
#define RelationCacheDelete(RELATION) \
do { \
RelIdCacheEnt *hentry; \
hentry = (RelIdCacheEnt *) hash_search(RelationIdCache, \
(void *) &((RELATION)->rd_id), \
HASH_REMOVE, NULL); \
if (hentry == NULL) \
elog(WARNING, "failed to delete relcache entry for OID %u", \
(RELATION)->rd_id); \
} while(0)
/*
* Special cache for opclass-related information
*
* Note: only default support procs get cached, ie, those with
* lefttype = righttype = opcintype.
*/
typedef struct opclasscacheent
{
Oid opclassoid; /* lookup key: OID of opclass */
bool valid; /* set true after successful fill-in */
StrategyNumber numSupport; /* max # of support procs (from pg_am) */
Oid opcfamily; /* OID of opclass's family */
Oid opcintype; /* OID of opclass's declared input type */
RegProcedure *supportProcs; /* OIDs of support procedures */
} OpClassCacheEnt;
static HTAB *OpClassCache = NULL;
/* non-export function prototypes */
static void RelationDestroyRelation(Relation relation, bool remember_tupdesc);
static void RelationClearRelation(Relation relation, bool rebuild);
static void RelationReloadIndexInfo(Relation relation);
static void RelationFlushRelation(Relation relation);
static void RememberToFreeTupleDescAtEOX(TupleDesc td);
static void AtEOXact_cleanup(Relation relation, bool isCommit);
static void AtEOSubXact_cleanup(Relation relation, bool isCommit,
SubTransactionId mySubid, SubTransactionId parentSubid);
static bool load_relcache_init_file(bool shared);
static void write_relcache_init_file(bool shared);
static void write_item(const void *data, Size len, FILE *fp);
static void formrdesc(const char *relationName, Oid relationReltype,
bool isshared, bool hasoids,
int natts, const FormData_pg_attribute *attrs);
static HeapTuple ScanPgRelation(Oid targetRelId, bool indexOK, bool force_non_historic);
static Relation AllocateRelationDesc(Form_pg_class relp);
static void RelationParseRelOptions(Relation relation, HeapTuple tuple);
static void RelationBuildTupleDesc(Relation relation);
static void RelationBuildPartitionKey(Relation relation);
static PartitionKey copy_partition_key(PartitionKey fromkey);
static Relation RelationBuildDesc(Oid targetRelId, bool insertIt);
static void RelationInitPhysicalAddr(Relation relation);
static void load_critical_index(Oid indexoid, Oid heapoid);
static TupleDesc GetPgClassDescriptor(void);
static TupleDesc GetPgIndexDescriptor(void);
static void AttrDefaultFetch(Relation relation);
static void CheckConstraintFetch(Relation relation);
static int CheckConstraintCmp(const void *a, const void *b);
static List *insert_ordered_oid(List *list, Oid datum);
static void InitIndexAmRoutine(Relation relation);
static void IndexSupportInitialize(oidvector *indclass,
RegProcedure *indexSupport,
Oid *opFamily,
Oid *opcInType,
StrategyNumber maxSupportNumber,
AttrNumber maxAttributeNumber);
static OpClassCacheEnt *LookupOpclassInfo(Oid operatorClassOid,
StrategyNumber numSupport);
static void RelationCacheInitFileRemoveInDir(const char *tblspcpath);
static void unlink_initfile(const char *initfilename);
static bool equalPartitionDescs(PartitionKey key, PartitionDesc partdesc1,
PartitionDesc partdesc2);
/*
* ScanPgRelation
*
* This is used by RelationBuildDesc to find a pg_class
* tuple matching targetRelId. The caller must hold at least
* AccessShareLock on the target relid to prevent concurrent-update
* scenarios; it isn't guaranteed that all scans used to build the
* relcache entry will use the same snapshot. If, for example,
* an attribute were to be added after scanning pg_class and before
* scanning pg_attribute, relnatts wouldn't match.
*
* NB: the returned tuple has been copied into palloc'd storage
* and must eventually be freed with heap_freetuple.
*/
static HeapTuple
ScanPgRelation(Oid targetRelId, bool indexOK, bool force_non_historic)
{
HeapTuple pg_class_tuple;
Relation pg_class_desc;
SysScanDesc pg_class_scan;
ScanKeyData key[1];
Snapshot snapshot;
/*
* If something goes wrong during backend startup, we might find ourselves
* trying to read pg_class before we've selected a database. That ain't
* gonna work, so bail out with a useful error message. If this happens,
* it probably means a relcache entry that needs to be nailed isn't.
*/
if (!OidIsValid(MyDatabaseId))
elog(FATAL, "cannot read pg_class without having selected a database");
/*
* form a scan key
*/
ScanKeyInit(&key[0],
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(targetRelId));
/*
* Open pg_class and fetch a tuple. Force heap scan if we haven't yet
* built the critical relcache entries (this includes initdb and startup
* without a pg_internal.init file). The caller can also force a heap
* scan by setting indexOK == false.
*/
pg_class_desc = heap_open(RelationRelationId, AccessShareLock);
/*
* The caller might need a tuple that's newer than the one the historic
* snapshot; currently the only case requiring to do so is looking up the
* relfilenode of non mapped system relations during decoding.
*/
if (force_non_historic)
snapshot = GetNonHistoricCatalogSnapshot(RelationRelationId);
else
snapshot = GetCatalogSnapshot(RelationRelationId);
pg_class_scan = systable_beginscan(pg_class_desc, ClassOidIndexId,
indexOK && criticalRelcachesBuilt,
snapshot,
1, key);
pg_class_tuple = systable_getnext(pg_class_scan);
/*
* Must copy tuple before releasing buffer.
*/
if (HeapTupleIsValid(pg_class_tuple))
pg_class_tuple = heap_copytuple(pg_class_tuple);
/* all done */
systable_endscan(pg_class_scan);
heap_close(pg_class_desc, AccessShareLock);
return pg_class_tuple;
}
/*
* AllocateRelationDesc
*
* This is used to allocate memory for a new relation descriptor
* and initialize the rd_rel field from the given pg_class tuple.
*/
static Relation
AllocateRelationDesc(Form_pg_class relp)
{
Relation relation;
MemoryContext oldcxt;
Form_pg_class relationForm;
/* Relcache entries must live in CacheMemoryContext */
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
/*
* allocate and zero space for new relation descriptor
*/
relation = (Relation) palloc0(sizeof(RelationData));
/* make sure relation is marked as having no open file yet */
relation->rd_smgr = NULL;
/*
* Copy the relation tuple form
*
* We only allocate space for the fixed fields, ie, CLASS_TUPLE_SIZE. The
* variable-length fields (relacl, reloptions) are NOT stored in the
* relcache --- there'd be little point in it, since we don't copy the
* tuple's nulls bitmap and hence wouldn't know if the values are valid.
* Bottom line is that relacl *cannot* be retrieved from the relcache. Get
* it from the syscache if you need it. The same goes for the original
* form of reloptions (however, we do store the parsed form of reloptions
* in rd_options).
*/
relationForm = (Form_pg_class) palloc(CLASS_TUPLE_SIZE);
memcpy(relationForm, relp, CLASS_TUPLE_SIZE);
/* initialize relation tuple form */
relation->rd_rel = relationForm;
/* and allocate attribute tuple form storage */
relation->rd_att = CreateTemplateTupleDesc(relationForm->relnatts,
relationForm->relhasoids);
/* which we mark as a reference-counted tupdesc */
relation->rd_att->tdrefcount = 1;
MemoryContextSwitchTo(oldcxt);
return relation;
}
/*
* RelationParseRelOptions
* Convert pg_class.reloptions into pre-parsed rd_options
*
* tuple is the real pg_class tuple (not rd_rel!) for relation
*
* Note: rd_rel and (if an index) rd_amroutine must be valid already
*/
static void
RelationParseRelOptions(Relation relation, HeapTuple tuple)
{
bytea *options;
relation->rd_options = NULL;
/* Fall out if relkind should not have options */
switch (relation->rd_rel->relkind)
{
case RELKIND_RELATION:
case RELKIND_TOASTVALUE:
case RELKIND_INDEX:
case RELKIND_VIEW:
case RELKIND_MATVIEW:
case RELKIND_PARTITIONED_TABLE:
break;
default:
return;
}
/*
* Fetch reloptions from tuple; have to use a hardwired descriptor because
* we might not have any other for pg_class yet (consider executing this
* code for pg_class itself)
*/
options = extractRelOptions(tuple,
GetPgClassDescriptor(),
relation->rd_rel->relkind == RELKIND_INDEX ?
relation->rd_amroutine->amoptions : NULL);
/*
* Copy parsed data into CacheMemoryContext. To guard against the
* possibility of leaks in the reloptions code, we want to do the actual
* parsing in the caller's memory context and copy the results into
* CacheMemoryContext after the fact.
*/
if (options)
{
relation->rd_options = MemoryContextAlloc(CacheMemoryContext,
VARSIZE(options));
memcpy(relation->rd_options, options, VARSIZE(options));
pfree(options);
}
}
/*
* RelationBuildTupleDesc
*
* Form the relation's tuple descriptor from information in
* the pg_attribute, pg_attrdef & pg_constraint system catalogs.
*/
static void
RelationBuildTupleDesc(Relation relation)
{
HeapTuple pg_attribute_tuple;
Relation pg_attribute_desc;
SysScanDesc pg_attribute_scan;
ScanKeyData skey[2];
int need;
TupleConstr *constr;
AttrDefault *attrdef = NULL;
int ndef = 0;
/* copy some fields from pg_class row to rd_att */
relation->rd_att->tdtypeid = relation->rd_rel->reltype;
relation->rd_att->tdtypmod = -1; /* unnecessary, but... */
relation->rd_att->tdhasoid = relation->rd_rel->relhasoids;
constr = (TupleConstr *) MemoryContextAlloc(CacheMemoryContext,
sizeof(TupleConstr));
constr->has_not_null = false;
/*
* Form a scan key that selects only user attributes (attnum > 0).
* (Eliminating system attribute rows at the index level is lots faster
* than fetching them.)
*/
ScanKeyInit(&skey[0],
Anum_pg_attribute_attrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
ScanKeyInit(&skey[1],
Anum_pg_attribute_attnum,
BTGreaterStrategyNumber, F_INT2GT,
Int16GetDatum(0));
/*
* Open pg_attribute and begin a scan. Force heap scan if we haven't yet
* built the critical relcache entries (this includes initdb and startup
* without a pg_internal.init file).
*/
pg_attribute_desc = heap_open(AttributeRelationId, AccessShareLock);
pg_attribute_scan = systable_beginscan(pg_attribute_desc,
AttributeRelidNumIndexId,
criticalRelcachesBuilt,
NULL,
2, skey);
/*
* add attribute data to relation->rd_att
*/
need = relation->rd_rel->relnatts;
while (HeapTupleIsValid(pg_attribute_tuple = systable_getnext(pg_attribute_scan)))
{
Form_pg_attribute attp;
attp = (Form_pg_attribute) GETSTRUCT(pg_attribute_tuple);
if (attp->attnum <= 0 ||
attp->attnum > relation->rd_rel->relnatts)
elog(ERROR, "invalid attribute number %d for %s",
attp->attnum, RelationGetRelationName(relation));
memcpy(TupleDescAttr(relation->rd_att, attp->attnum - 1),
attp,
ATTRIBUTE_FIXED_PART_SIZE);
/* Update constraint/default info */
if (attp->attnotnull)
constr->has_not_null = true;
if (attp->atthasdef)
{
if (attrdef == NULL)
attrdef = (AttrDefault *)
MemoryContextAllocZero(CacheMemoryContext,
relation->rd_rel->relnatts *
sizeof(AttrDefault));
attrdef[ndef].adnum = attp->attnum;
attrdef[ndef].adbin = NULL;
ndef++;
}
need--;
if (need == 0)
break;
}
/*
* end the scan and close the attribute relation
*/
systable_endscan(pg_attribute_scan);
heap_close(pg_attribute_desc, AccessShareLock);
if (need != 0)
elog(ERROR, "catalog is missing %d attribute(s) for relid %u",
need, RelationGetRelid(relation));
/*
* The attcacheoff values we read from pg_attribute should all be -1
* ("unknown"). Verify this if assert checking is on. They will be
* computed when and if needed during tuple access.
*/
#ifdef USE_ASSERT_CHECKING
{
int i;
for (i = 0; i < relation->rd_rel->relnatts; i++)
Assert(TupleDescAttr(relation->rd_att, i)->attcacheoff == -1);
}
#endif
/*
* However, we can easily set the attcacheoff value for the first
* attribute: it must be zero. This eliminates the need for special cases
* for attnum=1 that used to exist in fastgetattr() and index_getattr().
*/
if (relation->rd_rel->relnatts > 0)
TupleDescAttr(relation->rd_att, 0)->attcacheoff = 0;
/*
* Set up constraint/default info
*/
if (constr->has_not_null || ndef > 0 || relation->rd_rel->relchecks)
{
relation->rd_att->constr = constr;
if (ndef > 0) /* DEFAULTs */
{
if (ndef < relation->rd_rel->relnatts)
constr->defval = (AttrDefault *)
repalloc(attrdef, ndef * sizeof(AttrDefault));
else
constr->defval = attrdef;
constr->num_defval = ndef;
AttrDefaultFetch(relation);
}
else
constr->num_defval = 0;
if (relation->rd_rel->relchecks > 0) /* CHECKs */
{
constr->num_check = relation->rd_rel->relchecks;
constr->check = (ConstrCheck *)
MemoryContextAllocZero(CacheMemoryContext,
constr->num_check * sizeof(ConstrCheck));
CheckConstraintFetch(relation);
}
else
constr->num_check = 0;
}
else
{
pfree(constr);
relation->rd_att->constr = NULL;
}
}
/*
* RelationBuildRuleLock
*
* Form the relation's rewrite rules from information in
* the pg_rewrite system catalog.
*
* Note: The rule parsetrees are potentially very complex node structures.
* To allow these trees to be freed when the relcache entry is flushed,
* we make a private memory context to hold the RuleLock information for
* each relcache entry that has associated rules. The context is used
* just for rule info, not for any other subsidiary data of the relcache
* entry, because that keeps the update logic in RelationClearRelation()
* manageable. The other subsidiary data structures are simple enough
* to be easy to free explicitly, anyway.
*/
static void
RelationBuildRuleLock(Relation relation)
{
MemoryContext rulescxt;
MemoryContext oldcxt;
HeapTuple rewrite_tuple;
Relation rewrite_desc;
TupleDesc rewrite_tupdesc;
SysScanDesc rewrite_scan;
ScanKeyData key;
RuleLock *rulelock;
int numlocks;
RewriteRule **rules;
int maxlocks;
/*
* Make the private context. Assume it'll not contain much data.
*/
rulescxt = AllocSetContextCreateExtended(CacheMemoryContext,
RelationGetRelationName(relation),
MEMCONTEXT_COPY_NAME,
ALLOCSET_SMALL_SIZES);
relation->rd_rulescxt = rulescxt;
/*
* allocate an array to hold the rewrite rules (the array is extended if
* necessary)
*/
maxlocks = 4;
rules = (RewriteRule **)
MemoryContextAlloc(rulescxt, sizeof(RewriteRule *) * maxlocks);
numlocks = 0;
/*
* form a scan key
*/
ScanKeyInit(&key,
Anum_pg_rewrite_ev_class,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
/*
* open pg_rewrite and begin a scan
*
* Note: since we scan the rules using RewriteRelRulenameIndexId, we will
* be reading the rules in name order, except possibly during
* emergency-recovery operations (ie, IgnoreSystemIndexes). This in turn
* ensures that rules will be fired in name order.
*/
rewrite_desc = heap_open(RewriteRelationId, AccessShareLock);
rewrite_tupdesc = RelationGetDescr(rewrite_desc);
rewrite_scan = systable_beginscan(rewrite_desc,
RewriteRelRulenameIndexId,
true, NULL,
1, &key);
while (HeapTupleIsValid(rewrite_tuple = systable_getnext(rewrite_scan)))
{
Form_pg_rewrite rewrite_form = (Form_pg_rewrite) GETSTRUCT(rewrite_tuple);
bool isnull;
Datum rule_datum;
char *rule_str;
RewriteRule *rule;
rule = (RewriteRule *) MemoryContextAlloc(rulescxt,
sizeof(RewriteRule));
rule->ruleId = HeapTupleGetOid(rewrite_tuple);
rule->event = rewrite_form->ev_type - '0';
rule->enabled = rewrite_form->ev_enabled;
rule->isInstead = rewrite_form->is_instead;
/*
* Must use heap_getattr to fetch ev_action and ev_qual. Also, the
* rule strings are often large enough to be toasted. To avoid
* leaking memory in the caller's context, do the detoasting here so
* we can free the detoasted version.
*/
rule_datum = heap_getattr(rewrite_tuple,
Anum_pg_rewrite_ev_action,
rewrite_tupdesc,
&isnull);
Assert(!isnull);
rule_str = TextDatumGetCString(rule_datum);
oldcxt = MemoryContextSwitchTo(rulescxt);
rule->actions = (List *) stringToNode(rule_str);
MemoryContextSwitchTo(oldcxt);
pfree(rule_str);
rule_datum = heap_getattr(rewrite_tuple,
Anum_pg_rewrite_ev_qual,
rewrite_tupdesc,
&isnull);
Assert(!isnull);
rule_str = TextDatumGetCString(rule_datum);
oldcxt = MemoryContextSwitchTo(rulescxt);
rule->qual = (Node *) stringToNode(rule_str);
MemoryContextSwitchTo(oldcxt);
pfree(rule_str);
/*
* We want the rule's table references to be checked as though by the
* table owner, not the user referencing the rule. Therefore, scan
* through the rule's actions and set the checkAsUser field on all
* rtable entries. We have to look at the qual as well, in case it
* contains sublinks.
*
* The reason for doing this when the rule is loaded, rather than when
* it is stored, is that otherwise ALTER TABLE OWNER would have to
* grovel through stored rules to update checkAsUser fields. Scanning
* the rule tree during load is relatively cheap (compared to
* constructing it in the first place), so we do it here.
*/
setRuleCheckAsUser((Node *) rule->actions, relation->rd_rel->relowner);
setRuleCheckAsUser(rule->qual, relation->rd_rel->relowner);
if (numlocks >= maxlocks)
{
maxlocks *= 2;
rules = (RewriteRule **)
repalloc(rules, sizeof(RewriteRule *) * maxlocks);
}
rules[numlocks++] = rule;
}
/*
* end the scan and close the attribute relation
*/
systable_endscan(rewrite_scan);
heap_close(rewrite_desc, AccessShareLock);
/*
* there might not be any rules (if relhasrules is out-of-date)
*/
if (numlocks == 0)
{
relation->rd_rules = NULL;
relation->rd_rulescxt = NULL;
MemoryContextDelete(rulescxt);
return;
}
/*
* form a RuleLock and insert into relation
*/
rulelock = (RuleLock *) MemoryContextAlloc(rulescxt, sizeof(RuleLock));
rulelock->numLocks = numlocks;
rulelock->rules = rules;
relation->rd_rules = rulelock;
}
/*
* RelationBuildPartitionKey
* Build and attach to relcache partition key data of relation
*
* Partitioning key data is stored in CacheMemoryContext to ensure it survives
* as long as the relcache. To avoid leaking memory in that context in case
* of an error partway through this function, we build the structure in the
* working context (which must be short-lived) and copy the completed
* structure into the cache memory.
*
* Also, since the structure being created here is sufficiently complex, we
* make a private child context of CacheMemoryContext for each relation that
* has associated partition key information. That means no complicated logic
* to free individual elements whenever the relcache entry is flushed - just
* delete the context.
*/
static void
RelationBuildPartitionKey(Relation relation)
{
Form_pg_partitioned_table form;
HeapTuple tuple;
bool isnull;
int i;
PartitionKey key;
AttrNumber *attrs;
oidvector *opclass;
oidvector *collation;
ListCell *partexprs_item;
Datum datum;
MemoryContext partkeycxt,
oldcxt;
int16 procnum;
tuple = SearchSysCache1(PARTRELID,
ObjectIdGetDatum(RelationGetRelid(relation)));
/*
* The following happens when we have created our pg_class entry but not
* the pg_partitioned_table entry yet.
*/
if (!HeapTupleIsValid(tuple))
return;
key = (PartitionKey) palloc0(sizeof(PartitionKeyData));
/* Fixed-length attributes */
form = (Form_pg_partitioned_table) GETSTRUCT(tuple);
key->strategy = form->partstrat;
key->partnatts = form->partnatts;
/*
* We can rely on the first variable-length attribute being mapped to the
* relevant field of the catalog's C struct, because all previous
* attributes are non-nullable and fixed-length.
*/
attrs = form->partattrs.values;
/* But use the hard way to retrieve further variable-length attributes */
/* Operator class */
datum = SysCacheGetAttr(PARTRELID, tuple,
Anum_pg_partitioned_table_partclass, &isnull);
Assert(!isnull);
opclass = (oidvector *) DatumGetPointer(datum);
/* Collation */
datum = SysCacheGetAttr(PARTRELID, tuple,
Anum_pg_partitioned_table_partcollation, &isnull);
Assert(!isnull);
collation = (oidvector *) DatumGetPointer(datum);
/* Expressions */
datum = SysCacheGetAttr(PARTRELID, tuple,
Anum_pg_partitioned_table_partexprs, &isnull);
if (!isnull)
{
char *exprString;
Node *expr;
exprString = TextDatumGetCString(datum);
expr = stringToNode(exprString);
pfree(exprString);
/*
* Run the expressions through const-simplification since the planner
* will be comparing them to similarly-processed qual clause operands,
* and may fail to detect valid matches without this step. We don't
* need to bother with canonicalize_qual() though, because partition
* expressions are not full-fledged qualification clauses.
*/
expr = eval_const_expressions(NULL, (Node *) expr);
/* May as well fix opfuncids too */
fix_opfuncids((Node *) expr);
key->partexprs = (List *) expr;
}
key->partattrs = (AttrNumber *) palloc0(key->partnatts * sizeof(AttrNumber));
key->partopfamily = (Oid *) palloc0(key->partnatts * sizeof(Oid));
key->partopcintype = (Oid *) palloc0(key->partnatts * sizeof(Oid));
key->partsupfunc = (FmgrInfo *) palloc0(key->partnatts * sizeof(FmgrInfo));
key->partcollation = (Oid *) palloc0(key->partnatts * sizeof(Oid));
/* Gather type and collation info as well */
key->parttypid = (Oid *) palloc0(key->partnatts * sizeof(Oid));
key->parttypmod = (int32 *) palloc0(key->partnatts * sizeof(int32));
key->parttyplen = (int16 *) palloc0(key->partnatts * sizeof(int16));
key->parttypbyval = (bool *) palloc0(key->partnatts * sizeof(bool));
key->parttypalign = (char *) palloc0(key->partnatts * sizeof(char));
key->parttypcoll = (Oid *) palloc0(key->partnatts * sizeof(Oid));
/* For the hash partitioning, an extended hash function will be used. */
procnum = (key->strategy == PARTITION_STRATEGY_HASH) ?
HASHEXTENDED_PROC : BTORDER_PROC;
/* Copy partattrs and fill other per-attribute info */
memcpy(key->partattrs, attrs, key->partnatts * sizeof(int16));
partexprs_item = list_head(key->partexprs);
for (i = 0; i < key->partnatts; i++)
{
AttrNumber attno = key->partattrs[i];
HeapTuple opclasstup;
Form_pg_opclass opclassform;
Oid funcid;
/* Collect opfamily information */
opclasstup = SearchSysCache1(CLAOID,
ObjectIdGetDatum(opclass->values[i]));
if (!HeapTupleIsValid(opclasstup))
elog(ERROR, "cache lookup failed for opclass %u", opclass->values[i]);
opclassform = (Form_pg_opclass) GETSTRUCT(opclasstup);
key->partopfamily[i] = opclassform->opcfamily;
key->partopcintype[i] = opclassform->opcintype;
/* Get a support function for the specified opfamily and datatypes */
funcid = get_opfamily_proc(opclassform->opcfamily,
opclassform->opcintype,
opclassform->opcintype,
procnum);
if (!OidIsValid(funcid))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("operator class \"%s\" of access method %s is missing support function %d for data type \"%s\"",
NameStr(opclassform->opcname),
(key->strategy == PARTITION_STRATEGY_HASH) ?
"hash" : "btree",
procnum,
format_type_be(opclassform->opcintype))));
fmgr_info(funcid, &key->partsupfunc[i]);
/* Collation */
key->partcollation[i] = collation->values[i];
/* Collect type information */
if (attno != 0)
{
Form_pg_attribute att = TupleDescAttr(relation->rd_att, attno - 1);
key->parttypid[i] = att->atttypid;
key->parttypmod[i] = att->atttypmod;
key->parttypcoll[i] = att->attcollation;
}
else
{
key->parttypid[i] = exprType(lfirst(partexprs_item));
key->parttypmod[i] = exprTypmod(lfirst(partexprs_item));
key->parttypcoll[i] = exprCollation(lfirst(partexprs_item));
}
get_typlenbyvalalign(key->parttypid[i],
&key->parttyplen[i],
&key->parttypbyval[i],
&key->parttypalign[i]);
ReleaseSysCache(opclasstup);
}
ReleaseSysCache(tuple);
/* Success --- now copy to the cache memory */
partkeycxt = AllocSetContextCreateExtended(CacheMemoryContext,
RelationGetRelationName(relation),
MEMCONTEXT_COPY_NAME,
ALLOCSET_SMALL_SIZES);
relation->rd_partkeycxt = partkeycxt;
oldcxt = MemoryContextSwitchTo(relation->rd_partkeycxt);
relation->rd_partkey = copy_partition_key(key);
MemoryContextSwitchTo(oldcxt);
}
/*
* copy_partition_key
*
* The copy is allocated in the current memory context.
*/
static PartitionKey
copy_partition_key(PartitionKey fromkey)
{
PartitionKey newkey;
int n;
newkey = (PartitionKey) palloc(sizeof(PartitionKeyData));
newkey->strategy = fromkey->strategy;
newkey->partnatts = n = fromkey->partnatts;
newkey->partattrs = (AttrNumber *) palloc(n * sizeof(AttrNumber));
memcpy(newkey->partattrs, fromkey->partattrs, n * sizeof(AttrNumber));
newkey->partexprs = copyObject(fromkey->partexprs);
newkey->partopfamily = (Oid *) palloc(n * sizeof(Oid));
memcpy(newkey->partopfamily, fromkey->partopfamily, n * sizeof(Oid));
newkey->partopcintype = (Oid *) palloc(n * sizeof(Oid));
memcpy(newkey->partopcintype, fromkey->partopcintype, n * sizeof(Oid));
newkey->partsupfunc = (FmgrInfo *) palloc(n * sizeof(FmgrInfo));
memcpy(newkey->partsupfunc, fromkey->partsupfunc, n * sizeof(FmgrInfo));
newkey->partcollation = (Oid *) palloc(n * sizeof(Oid));
memcpy(newkey->partcollation, fromkey->partcollation, n * sizeof(Oid));
newkey->parttypid = (Oid *) palloc(n * sizeof(Oid));
memcpy(newkey->parttypid, fromkey->parttypid, n * sizeof(Oid));
newkey->parttypmod = (int32 *) palloc(n * sizeof(int32));
memcpy(newkey->parttypmod, fromkey->parttypmod, n * sizeof(int32));
newkey->parttyplen = (int16 *) palloc(n * sizeof(int16));
memcpy(newkey->parttyplen, fromkey->parttyplen, n * sizeof(int16));
newkey->parttypbyval = (bool *) palloc(n * sizeof(bool));
memcpy(newkey->parttypbyval, fromkey->parttypbyval, n * sizeof(bool));
newkey->parttypalign = (char *) palloc(n * sizeof(bool));
memcpy(newkey->parttypalign, fromkey->parttypalign, n * sizeof(char));
newkey->parttypcoll = (Oid *) palloc(n * sizeof(Oid));
memcpy(newkey->parttypcoll, fromkey->parttypcoll, n * sizeof(Oid));
return newkey;
}
/*
* equalRuleLocks
*
* Determine whether two RuleLocks are equivalent
*
* Probably this should be in the rules code someplace...
*/
static bool
equalRuleLocks(RuleLock *rlock1, RuleLock *rlock2)
{
int i;
/*
* As of 7.3 we assume the rule ordering is repeatable, because
* RelationBuildRuleLock should read 'em in a consistent order. So just
* compare corresponding slots.
*/
if (rlock1 != NULL)
{
if (rlock2 == NULL)
return false;
if (rlock1->numLocks != rlock2->numLocks)
return false;
for (i = 0; i < rlock1->numLocks; i++)
{
RewriteRule *rule1 = rlock1->rules[i];
RewriteRule *rule2 = rlock2->rules[i];
if (rule1->ruleId != rule2->ruleId)
return false;
if (rule1->event != rule2->event)
return false;
if (rule1->enabled != rule2->enabled)
return false;
if (rule1->isInstead != rule2->isInstead)
return false;
if (!equal(rule1->qual, rule2->qual))
return false;
if (!equal(rule1->actions, rule2->actions))
return false;
}
}
else if (rlock2 != NULL)
return false;
return true;
}
/*
* equalPolicy
*
* Determine whether two policies are equivalent
*/
static bool
equalPolicy(RowSecurityPolicy *policy1, RowSecurityPolicy *policy2)
{
int i;
Oid *r1,
*r2;
if (policy1 != NULL)
{
if (policy2 == NULL)
return false;
if (policy1->polcmd != policy2->polcmd)
return false;
if (policy1->hassublinks != policy2->hassublinks)
return false;
if (strcmp(policy1->policy_name, policy2->policy_name) != 0)
return false;
if (ARR_DIMS(policy1->roles)[0] != ARR_DIMS(policy2->roles)[0])
return false;
r1 = (Oid *) ARR_DATA_PTR(policy1->roles);
r2 = (Oid *) ARR_DATA_PTR(policy2->roles);
for (i = 0; i < ARR_DIMS(policy1->roles)[0]; i++)
{
if (r1[i] != r2[i])
return false;
}
if (!equal(policy1->qual, policy2->qual))
return false;
if (!equal(policy1->with_check_qual, policy2->with_check_qual))
return false;
}
else if (policy2 != NULL)
return false;
return true;
}
/*
* equalRSDesc
*
* Determine whether two RowSecurityDesc's are equivalent
*/
static bool
equalRSDesc(RowSecurityDesc *rsdesc1, RowSecurityDesc *rsdesc2)
{
ListCell *lc,
*rc;
if (rsdesc1 == NULL && rsdesc2 == NULL)
return true;
if ((rsdesc1 != NULL && rsdesc2 == NULL) ||
(rsdesc1 == NULL && rsdesc2 != NULL))
return false;
if (list_length(rsdesc1->policies) != list_length(rsdesc2->policies))
return false;
/* RelationBuildRowSecurity should build policies in order */
forboth(lc, rsdesc1->policies, rc, rsdesc2->policies)
{
RowSecurityPolicy *l = (RowSecurityPolicy *) lfirst(lc);
RowSecurityPolicy *r = (RowSecurityPolicy *) lfirst(rc);
if (!equalPolicy(l, r))
return false;
}
return true;
}
/*
* equalPartitionDescs
* Compare two partition descriptors for logical equality
*/
static bool
equalPartitionDescs(PartitionKey key, PartitionDesc partdesc1,
PartitionDesc partdesc2)
{
int i;
if (partdesc1 != NULL)
{
if (partdesc2 == NULL)
return false;
if (partdesc1->nparts != partdesc2->nparts)
return false;
Assert(key != NULL || partdesc1->nparts == 0);
/*
* Same oids? If the partitioning structure did not change, that is,
* no partitions were added or removed to the relation, the oids array
* should still match element-by-element.
*/
for (i = 0; i < partdesc1->nparts; i++)
{
if (partdesc1->oids[i] != partdesc2->oids[i])
return false;
}
/*
* Now compare partition bound collections. The logic to iterate over
* the collections is private to partition.c.
*/
if (partdesc1->boundinfo != NULL)
{
if (partdesc2->boundinfo == NULL)
return false;
if (!partition_bounds_equal(key->partnatts, key->parttyplen,
key->parttypbyval,
partdesc1->boundinfo,
partdesc2->boundinfo))
return false;
}
else if (partdesc2->boundinfo != NULL)
return false;
}
else if (partdesc2 != NULL)
return false;
return true;
}
/*
* RelationBuildDesc
*
* Build a relation descriptor. The caller must hold at least
* AccessShareLock on the target relid.
*
* The new descriptor is inserted into the hash table if insertIt is true.
*
* Returns NULL if no pg_class row could be found for the given relid
* (suggesting we are trying to access a just-deleted relation).
* Any other error is reported via elog.
*/
static Relation
RelationBuildDesc(Oid targetRelId, bool insertIt)
{
Relation relation;
Oid relid;
HeapTuple pg_class_tuple;
Form_pg_class relp;
/*
* find the tuple in pg_class corresponding to the given relation id
*/
pg_class_tuple = ScanPgRelation(targetRelId, true, false);
/*
* if no such tuple exists, return NULL
*/
if (!HeapTupleIsValid(pg_class_tuple))
return NULL;
/*
* get information from the pg_class_tuple
*/
relid = HeapTupleGetOid(pg_class_tuple);
relp = (Form_pg_class) GETSTRUCT(pg_class_tuple);
Assert(relid == targetRelId);
/*
* allocate storage for the relation descriptor, and copy pg_class_tuple
* to relation->rd_rel.
*/
relation = AllocateRelationDesc(relp);
/*
* initialize the relation's relation id (relation->rd_id)
*/
RelationGetRelid(relation) = relid;
/*
* normal relations are not nailed into the cache; nor can a pre-existing
* relation be new. It could be temp though. (Actually, it could be new
* too, but it's okay to forget that fact if forced to flush the entry.)
*/
relation->rd_refcnt = 0;
relation->rd_isnailed = false;
relation->rd_createSubid = InvalidSubTransactionId;
relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
switch (relation->rd_rel->relpersistence)
{
case RELPERSISTENCE_UNLOGGED:
case RELPERSISTENCE_PERMANENT:
relation->rd_backend = InvalidBackendId;
relation->rd_islocaltemp = false;
break;
case RELPERSISTENCE_TEMP:
if (isTempOrTempToastNamespace(relation->rd_rel->relnamespace))
{
relation->rd_backend = BackendIdForTempRelations();
relation->rd_islocaltemp = true;
}
else
{
/*
* If it's a temp table, but not one of ours, we have to use
* the slow, grotty method to figure out the owning backend.
*
* Note: it's possible that rd_backend gets set to MyBackendId
* here, in case we are looking at a pg_class entry left over
* from a crashed backend that coincidentally had the same
* BackendId we're using. We should *not* consider such a
* table to be "ours"; this is why we need the separate
* rd_islocaltemp flag. The pg_class entry will get flushed
* if/when we clean out the corresponding temp table namespace
* in preparation for using it.
*/
relation->rd_backend =
GetTempNamespaceBackendId(relation->rd_rel->relnamespace);
Assert(relation->rd_backend != InvalidBackendId);
relation->rd_islocaltemp = false;
}
break;
default:
elog(ERROR, "invalid relpersistence: %c",
relation->rd_rel->relpersistence);
break;
}
/*
* initialize the tuple descriptor (relation->rd_att).
*/
RelationBuildTupleDesc(relation);
/*
* Fetch rules and triggers that affect this relation
*/
if (relation->rd_rel->relhasrules)
RelationBuildRuleLock(relation);
else
{
relation->rd_rules = NULL;
relation->rd_rulescxt = NULL;
}
if (relation->rd_rel->relhastriggers)
RelationBuildTriggers(relation);
else
relation->trigdesc = NULL;
if (relation->rd_rel->relrowsecurity)
RelationBuildRowSecurity(relation);
else
relation->rd_rsdesc = NULL;
/* foreign key data is not loaded till asked for */
relation->rd_fkeylist = NIL;
relation->rd_fkeyvalid = false;
/* if a partitioned table, initialize key and partition descriptor info */
if (relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
{
RelationBuildPartitionKey(relation);
RelationBuildPartitionDesc(relation);
}
else
{
relation->rd_partkeycxt = NULL;
relation->rd_partkey = NULL;
relation->rd_partdesc = NULL;
relation->rd_pdcxt = NULL;
}
/*
* if it's an index, initialize index-related information
*/
if (OidIsValid(relation->rd_rel->relam))
RelationInitIndexAccessInfo(relation);
/* extract reloptions if any */
RelationParseRelOptions(relation, pg_class_tuple);
/*
* initialize the relation lock manager information
*/
RelationInitLockInfo(relation); /* see lmgr.c */
/*
* initialize physical addressing information for the relation
*/
RelationInitPhysicalAddr(relation);
/* make sure relation is marked as having no open file yet */
relation->rd_smgr = NULL;
/*
* now we can free the memory allocated for pg_class_tuple
*/
heap_freetuple(pg_class_tuple);
/*
* Insert newly created relation into relcache hash table, if requested.
*
* There is one scenario in which we might find a hashtable entry already
* present, even though our caller failed to find it: if the relation is a
* system catalog or index that's used during relcache load, we might have
* recursively created the same relcache entry during the preceding steps.
* So allow RelationCacheInsert to delete any already-present relcache
* entry for the same OID. The already-present entry should have refcount
* zero (else somebody forgot to close it); in the event that it doesn't,
* we'll elog a WARNING and leak the already-present entry.
*/
if (insertIt)
RelationCacheInsert(relation, true);
/* It's fully valid */
relation->rd_isvalid = true;
return relation;
}
/*
* Initialize the physical addressing info (RelFileNode) for a relcache entry
*
* Note: at the physical level, relations in the pg_global tablespace must
* be treated as shared, even if relisshared isn't set. Hence we do not
* look at relisshared here.
*/
static void
RelationInitPhysicalAddr(Relation relation)
{
if (relation->rd_rel->reltablespace)
relation->rd_node.spcNode = relation->rd_rel->reltablespace;
else
relation->rd_node.spcNode = MyDatabaseTableSpace;
if (relation->rd_node.spcNode == GLOBALTABLESPACE_OID)
relation->rd_node.dbNode = InvalidOid;
else
relation->rd_node.dbNode = MyDatabaseId;
if (relation->rd_rel->relfilenode)
{
/*
* Even if we are using a decoding snapshot that doesn't represent the
* current state of the catalog we need to make sure the filenode
* points to the current file since the older file will be gone (or
* truncated). The new file will still contain older rows so lookups
* in them will work correctly. This wouldn't work correctly if
* rewrites were allowed to change the schema in an incompatible way,
* but those are prevented both on catalog tables and on user tables
* declared as additional catalog tables.
*/
if (HistoricSnapshotActive()
&& RelationIsAccessibleInLogicalDecoding(relation)
&& IsTransactionState())
{
HeapTuple phys_tuple;
Form_pg_class physrel;
phys_tuple = ScanPgRelation(RelationGetRelid(relation),
RelationGetRelid(relation) != ClassOidIndexId,
true);
if (!HeapTupleIsValid(phys_tuple))
elog(ERROR, "could not find pg_class entry for %u",
RelationGetRelid(relation));
physrel = (Form_pg_class) GETSTRUCT(phys_tuple);
relation->rd_rel->reltablespace = physrel->reltablespace;
relation->rd_rel->relfilenode = physrel->relfilenode;
heap_freetuple(phys_tuple);
}
relation->rd_node.relNode = relation->rd_rel->relfilenode;
}
else
{
/* Consult the relation mapper */
relation->rd_node.relNode =
RelationMapOidToFilenode(relation->rd_id,
relation->rd_rel->relisshared);
if (!OidIsValid(relation->rd_node.relNode))
elog(ERROR, "could not find relation mapping for relation \"%s\", OID %u",
RelationGetRelationName(relation), relation->rd_id);
}
}
/*
* Fill in the IndexAmRoutine for an index relation.
*
* relation's rd_amhandler and rd_indexcxt must be valid already.
*/
static void
InitIndexAmRoutine(Relation relation)
{
IndexAmRoutine *cached,
*tmp;
/*
* Call the amhandler in current, short-lived memory context, just in case
* it leaks anything (it probably won't, but let's be paranoid).
*/
tmp = GetIndexAmRoutine(relation->rd_amhandler);
/* OK, now transfer the data into relation's rd_indexcxt. */
cached = (IndexAmRoutine *) MemoryContextAlloc(relation->rd_indexcxt,
sizeof(IndexAmRoutine));
memcpy(cached, tmp, sizeof(IndexAmRoutine));
relation->rd_amroutine = cached;
pfree(tmp);
}
/*
* Initialize index-access-method support data for an index relation
*/
void
RelationInitIndexAccessInfo(Relation relation)
{
HeapTuple tuple;
Form_pg_am aform;
Datum indcollDatum;
Datum indclassDatum;
Datum indoptionDatum;
bool isnull;
oidvector *indcoll;
oidvector *indclass;
int2vector *indoption;
MemoryContext indexcxt;
MemoryContext oldcontext;
int natts;
uint16 amsupport;
/*
* Make a copy of the pg_index entry for the index. Since pg_index
* contains variable-length and possibly-null fields, we have to do this
* honestly rather than just treating it as a Form_pg_index struct.
*/
tuple = SearchSysCache1(INDEXRELID,
ObjectIdGetDatum(RelationGetRelid(relation)));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for index %u",
RelationGetRelid(relation));
oldcontext = MemoryContextSwitchTo(CacheMemoryContext);
relation->rd_indextuple = heap_copytuple(tuple);
relation->rd_index = (Form_pg_index) GETSTRUCT(relation->rd_indextuple);
MemoryContextSwitchTo(oldcontext);
ReleaseSysCache(tuple);
/*
* Look up the index's access method, save the OID of its handler function
*/
tuple = SearchSysCache1(AMOID, ObjectIdGetDatum(relation->rd_rel->relam));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for access method %u",
relation->rd_rel->relam);
aform = (Form_pg_am) GETSTRUCT(tuple);
relation->rd_amhandler = aform->amhandler;
ReleaseSysCache(tuple);
natts = relation->rd_rel->relnatts;
if (natts != relation->rd_index->indnatts)
elog(ERROR, "relnatts disagrees with indnatts for index %u",
RelationGetRelid(relation));
/*
* Make the private context to hold index access info. The reason we need
* a context, and not just a couple of pallocs, is so that we won't leak
* any subsidiary info attached to fmgr lookup records.
*/
indexcxt = AllocSetContextCreateExtended(CacheMemoryContext,
RelationGetRelationName(relation),
MEMCONTEXT_COPY_NAME,
ALLOCSET_SMALL_SIZES);
relation->rd_indexcxt = indexcxt;
/*
* Now we can fetch the index AM's API struct
*/
InitIndexAmRoutine(relation);
/*
* Allocate arrays to hold data
*/
relation->rd_opfamily = (Oid *)
MemoryContextAllocZero(indexcxt, natts * sizeof(Oid));
relation->rd_opcintype = (Oid *)
MemoryContextAllocZero(indexcxt, natts * sizeof(Oid));
amsupport = relation->rd_amroutine->amsupport;
if (amsupport > 0)
{
int nsupport = natts * amsupport;
relation->rd_support = (RegProcedure *)
MemoryContextAllocZero(indexcxt, nsupport * sizeof(RegProcedure));
relation->rd_supportinfo = (FmgrInfo *)
MemoryContextAllocZero(indexcxt, nsupport * sizeof(FmgrInfo));
}
else
{
relation->rd_support = NULL;
relation->rd_supportinfo = NULL;
}
relation->rd_indcollation = (Oid *)
MemoryContextAllocZero(indexcxt, natts * sizeof(Oid));
relation->rd_indoption = (int16 *)
MemoryContextAllocZero(indexcxt, natts * sizeof(int16));
/*
* indcollation cannot be referenced directly through the C struct,
* because it comes after the variable-width indkey field. Must extract
* the datum the hard way...
*/
indcollDatum = fastgetattr(relation->rd_indextuple,
Anum_pg_index_indcollation,
GetPgIndexDescriptor(),
&isnull);
Assert(!isnull);
indcoll = (oidvector *) DatumGetPointer(indcollDatum);
memcpy(relation->rd_indcollation, indcoll->values, natts * sizeof(Oid));
/*
* indclass cannot be referenced directly through the C struct, because it
* comes after the variable-width indkey field. Must extract the datum
* the hard way...
*/
indclassDatum = fastgetattr(relation->rd_indextuple,
Anum_pg_index_indclass,
GetPgIndexDescriptor(),
&isnull);
Assert(!isnull);
indclass = (oidvector *) DatumGetPointer(indclassDatum);
/*
* Fill the support procedure OID array, as well as the info about
* opfamilies and opclass input types. (aminfo and supportinfo are left
* as zeroes, and are filled on-the-fly when used)
*/
IndexSupportInitialize(indclass, relation->rd_support,
relation->rd_opfamily, relation->rd_opcintype,
amsupport, natts);
/*
* Similarly extract indoption and copy it to the cache entry
*/
indoptionDatum = fastgetattr(relation->rd_indextuple,
Anum_pg_index_indoption,
GetPgIndexDescriptor(),
&isnull);
Assert(!isnull);
indoption = (int2vector *) DatumGetPointer(indoptionDatum);
memcpy(relation->rd_indoption, indoption->values, natts * sizeof(int16));
/*
* expressions, predicate, exclusion caches will be filled later
*/
relation->rd_indexprs = NIL;
relation->rd_indpred = NIL;
relation->rd_exclops = NULL;
relation->rd_exclprocs = NULL;
relation->rd_exclstrats = NULL;
relation->rd_amcache = NULL;
}
/*
* IndexSupportInitialize
* Initializes an index's cached opclass information,
* given the index's pg_index.indclass entry.
*
* Data is returned into *indexSupport, *opFamily, and *opcInType,
* which are arrays allocated by the caller.
*
* The caller also passes maxSupportNumber and maxAttributeNumber, since these
* indicate the size of the arrays it has allocated --- but in practice these
* numbers must always match those obtainable from the system catalog entries
* for the index and access method.
*/
static void
IndexSupportInitialize(oidvector *indclass,
RegProcedure *indexSupport,
Oid *opFamily,
Oid *opcInType,
StrategyNumber maxSupportNumber,
AttrNumber maxAttributeNumber)
{
int attIndex;
for (attIndex = 0; attIndex < maxAttributeNumber; attIndex++)
{
OpClassCacheEnt *opcentry;
if (!OidIsValid(indclass->values[attIndex]))
elog(ERROR, "bogus pg_index tuple");
/* look up the info for this opclass, using a cache */
opcentry = LookupOpclassInfo(indclass->values[attIndex],
maxSupportNumber);
/* copy cached data into relcache entry */
opFamily[attIndex] = opcentry->opcfamily;
opcInType[attIndex] = opcentry->opcintype;
if (maxSupportNumber > 0)
memcpy(&indexSupport[attIndex * maxSupportNumber],
opcentry->supportProcs,
maxSupportNumber * sizeof(RegProcedure));
}
}
/*
* LookupOpclassInfo
*
* This routine maintains a per-opclass cache of the information needed
* by IndexSupportInitialize(). This is more efficient than relying on
* the catalog cache, because we can load all the info about a particular
* opclass in a single indexscan of pg_amproc.
*
* The information from pg_am about expected range of support function
* numbers is passed in, rather than being looked up, mainly because the
* caller will have it already.
*
* Note there is no provision for flushing the cache. This is OK at the
* moment because there is no way to ALTER any interesting properties of an
* existing opclass --- all you can do is drop it, which will result in
* a useless but harmless dead entry in the cache. To support altering
* opclass membership (not the same as opfamily membership!), we'd need to
* be able to flush this cache as well as the contents of relcache entries
* for indexes.
*/
static OpClassCacheEnt *
LookupOpclassInfo(Oid operatorClassOid,
StrategyNumber numSupport)
{
OpClassCacheEnt *opcentry;
bool found;
Relation rel;
SysScanDesc scan;
ScanKeyData skey[3];
HeapTuple htup;
bool indexOK;
if (OpClassCache == NULL)
{
/* First time through: initialize the opclass cache */
HASHCTL ctl;
MemSet(&ctl, 0, sizeof(ctl));
ctl.keysize = sizeof(Oid);
ctl.entrysize = sizeof(OpClassCacheEnt);
OpClassCache = hash_create("Operator class cache", 64,
&ctl, HASH_ELEM | HASH_BLOBS);
/* Also make sure CacheMemoryContext exists */
if (!CacheMemoryContext)
CreateCacheMemoryContext();
}
opcentry = (OpClassCacheEnt *) hash_search(OpClassCache,
(void *) &operatorClassOid,
HASH_ENTER, &found);
if (!found)
{
/* Need to allocate memory for new entry */
opcentry->valid = false; /* until known OK */
opcentry->numSupport = numSupport;
if (numSupport > 0)
opcentry->supportProcs = (RegProcedure *)
MemoryContextAllocZero(CacheMemoryContext,
numSupport * sizeof(RegProcedure));
else
opcentry->supportProcs = NULL;
}
else
{
Assert(numSupport == opcentry->numSupport);
}
/*
* When testing for cache-flush hazards, we intentionally disable the
* operator class cache and force reloading of the info on each call. This
* is helpful because we want to test the case where a cache flush occurs
* while we are loading the info, and it's very hard to provoke that if
* this happens only once per opclass per backend.
*/
#if defined(CLOBBER_CACHE_ALWAYS)
opcentry->valid = false;
#endif
if (opcentry->valid)
return opcentry;
/*
* Need to fill in new entry.
*
* To avoid infinite recursion during startup, force heap scans if we're
* looking up info for the opclasses used by the indexes we would like to
* reference here.
*/
indexOK = criticalRelcachesBuilt ||
(operatorClassOid != OID_BTREE_OPS_OID &&
operatorClassOid != INT2_BTREE_OPS_OID);
/*
* We have to fetch the pg_opclass row to determine its opfamily and
* opcintype, which are needed to look up related operators and functions.
* It'd be convenient to use the syscache here, but that probably doesn't
* work while bootstrapping.
*/
ScanKeyInit(&skey[0],
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(operatorClassOid));
rel = heap_open(OperatorClassRelationId, AccessShareLock);
scan = systable_beginscan(rel, OpclassOidIndexId, indexOK,
NULL, 1, skey);
if (HeapTupleIsValid(htup = systable_getnext(scan)))
{
Form_pg_opclass opclassform = (Form_pg_opclass) GETSTRUCT(htup);
opcentry->opcfamily = opclassform->opcfamily;
opcentry->opcintype = opclassform->opcintype;
}
else
elog(ERROR, "could not find tuple for opclass %u", operatorClassOid);
systable_endscan(scan);
heap_close(rel, AccessShareLock);
/*
* Scan pg_amproc to obtain support procs for the opclass. We only fetch
* the default ones (those with lefttype = righttype = opcintype).
*/
if (numSupport > 0)
{
ScanKeyInit(&skey[0],
Anum_pg_amproc_amprocfamily,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(opcentry->opcfamily));
ScanKeyInit(&skey[1],
Anum_pg_amproc_amproclefttype,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(opcentry->opcintype));
ScanKeyInit(&skey[2],
Anum_pg_amproc_amprocrighttype,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(opcentry->opcintype));
rel = heap_open(AccessMethodProcedureRelationId, AccessShareLock);
scan = systable_beginscan(rel, AccessMethodProcedureIndexId, indexOK,
NULL, 3, skey);
while (HeapTupleIsValid(htup = systable_getnext(scan)))
{
Form_pg_amproc amprocform = (Form_pg_amproc) GETSTRUCT(htup);
if (amprocform->amprocnum <= 0 ||
(StrategyNumber) amprocform->amprocnum > numSupport)
elog(ERROR, "invalid amproc number %d for opclass %u",
amprocform->amprocnum, operatorClassOid);
opcentry->supportProcs[amprocform->amprocnum - 1] =
amprocform->amproc;
}
systable_endscan(scan);
heap_close(rel, AccessShareLock);
}
opcentry->valid = true;
return opcentry;
}
/*
* formrdesc
*
* This is a special cut-down version of RelationBuildDesc(),
* used while initializing the relcache.
* The relation descriptor is built just from the supplied parameters,
* without actually looking at any system table entries. We cheat
* quite a lot since we only need to work for a few basic system
* catalogs.
*
* formrdesc is currently used for: pg_database, pg_authid, pg_auth_members,
* pg_shseclabel, pg_class, pg_attribute, pg_proc, and pg_type
* (see RelationCacheInitializePhase2/3).
*
* Note that these catalogs can't have constraints (except attnotnull),
* default values, rules, or triggers, since we don't cope with any of that.
* (Well, actually, this only matters for properties that need to be valid
* during bootstrap or before RelationCacheInitializePhase3 runs, and none of
* these properties matter then...)
*
* NOTE: we assume we are already switched into CacheMemoryContext.
*/
static void
formrdesc(const char *relationName, Oid relationReltype,
bool isshared, bool hasoids,
int natts, const FormData_pg_attribute *attrs)
{
Relation relation;
int i;
bool has_not_null;
/*
* allocate new relation desc, clear all fields of reldesc
*/
relation = (Relation) palloc0(sizeof(RelationData));
/* make sure relation is marked as having no open file yet */
relation->rd_smgr = NULL;
/*
* initialize reference count: 1 because it is nailed in cache
*/
relation->rd_refcnt = 1;
/*
* all entries built with this routine are nailed-in-cache; none are for
* new or temp relations.
*/
relation->rd_isnailed = true;
relation->rd_createSubid = InvalidSubTransactionId;
relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
relation->rd_backend = InvalidBackendId;
relation->rd_islocaltemp = false;
/*
* initialize relation tuple form
*
* The data we insert here is pretty incomplete/bogus, but it'll serve to
* get us launched. RelationCacheInitializePhase3() will read the real
* data from pg_class and replace what we've done here. Note in
* particular that relowner is left as zero; this cues
* RelationCacheInitializePhase3 that the real data isn't there yet.
*/
relation->rd_rel = (Form_pg_class) palloc0(CLASS_TUPLE_SIZE);
namestrcpy(&relation->rd_rel->relname, relationName);
relation->rd_rel->relnamespace = PG_CATALOG_NAMESPACE;
relation->rd_rel->reltype = relationReltype;
/*
* It's important to distinguish between shared and non-shared relations,
* even at bootstrap time, to make sure we know where they are stored.
*/
relation->rd_rel->relisshared = isshared;
if (isshared)
relation->rd_rel->reltablespace = GLOBALTABLESPACE_OID;
/* formrdesc is used only for permanent relations */
relation->rd_rel->relpersistence = RELPERSISTENCE_PERMANENT;
/* ... and they're always populated, too */
relation->rd_rel->relispopulated = true;
relation->rd_rel->relreplident = REPLICA_IDENTITY_NOTHING;
relation->rd_rel->relpages = 0;
relation->rd_rel->reltuples = 0;
relation->rd_rel->relallvisible = 0;
relation->rd_rel->relkind = RELKIND_RELATION;
relation->rd_rel->relhasoids = hasoids;
relation->rd_rel->relnatts = (int16) natts;
/*
* initialize attribute tuple form
*
* Unlike the case with the relation tuple, this data had better be right
* because it will never be replaced. The data comes from
* src/include/catalog/ headers via genbki.pl.
*/
relation->rd_att = CreateTemplateTupleDesc(natts, hasoids);
relation->rd_att->tdrefcount = 1; /* mark as refcounted */
relation->rd_att->tdtypeid = relationReltype;
relation->rd_att->tdtypmod = -1; /* unnecessary, but... */
/*
* initialize tuple desc info
*/
has_not_null = false;
for (i = 0; i < natts; i++)
{
memcpy(TupleDescAttr(relation->rd_att, i),
&attrs[i],
ATTRIBUTE_FIXED_PART_SIZE);
has_not_null |= attrs[i].attnotnull;
/* make sure attcacheoff is valid */
TupleDescAttr(relation->rd_att, i)->attcacheoff = -1;
}
/* initialize first attribute's attcacheoff, cf RelationBuildTupleDesc */
TupleDescAttr(relation->rd_att, 0)->attcacheoff = 0;
/* mark not-null status */
if (has_not_null)
{
TupleConstr *constr = (TupleConstr *) palloc0(sizeof(TupleConstr));
constr->has_not_null = true;
relation->rd_att->constr = constr;
}
/*
* initialize relation id from info in att array (my, this is ugly)
*/
RelationGetRelid(relation) = TupleDescAttr(relation->rd_att, 0)->attrelid;
/*
* All relations made with formrdesc are mapped. This is necessarily so
* because there is no other way to know what filenode they currently
* have. In bootstrap mode, add them to the initial relation mapper data,
* specifying that the initial filenode is the same as the OID.
*/
relation->rd_rel->relfilenode = InvalidOid;
if (IsBootstrapProcessingMode())
RelationMapUpdateMap(RelationGetRelid(relation),
RelationGetRelid(relation),
isshared, true);
/*
* initialize the relation lock manager information
*/
RelationInitLockInfo(relation); /* see lmgr.c */
/*
* initialize physical addressing information for the relation
*/
RelationInitPhysicalAddr(relation);
/*
* initialize the rel-has-index flag, using hardwired knowledge
*/
if (IsBootstrapProcessingMode())
{
/* In bootstrap mode, we have no indexes */
relation->rd_rel->relhasindex = false;
}
else
{
/* Otherwise, all the rels formrdesc is used for have indexes */
relation->rd_rel->relhasindex = true;
}
/*
* add new reldesc to relcache
*/
RelationCacheInsert(relation, false);
/* It's fully valid */
relation->rd_isvalid = true;
}
/* ----------------------------------------------------------------
* Relation Descriptor Lookup Interface
* ----------------------------------------------------------------
*/
/*
* RelationIdGetRelation
*
* Lookup a reldesc by OID; make one if not already in cache.
*
* Returns NULL if no pg_class row could be found for the given relid
* (suggesting we are trying to access a just-deleted relation).
* Any other error is reported via elog.
*
* NB: caller should already have at least AccessShareLock on the
* relation ID, else there are nasty race conditions.
*
* NB: relation ref count is incremented, or set to 1 if new entry.
* Caller should eventually decrement count. (Usually,
* that happens by calling RelationClose().)
*/
Relation
RelationIdGetRelation(Oid relationId)
{
Relation rd;
/* Make sure we're in an xact, even if this ends up being a cache hit */
Assert(IsTransactionState());
/*
* first try to find reldesc in the cache
*/
RelationIdCacheLookup(relationId, rd);
if (RelationIsValid(rd))
{
RelationIncrementReferenceCount(rd);
/* revalidate cache entry if necessary */
if (!rd->rd_isvalid)
{
/*
* Indexes only have a limited number of possible schema changes,
* and we don't want to use the full-blown procedure because it's
* a headache for indexes that reload itself depends on.
*/
if (rd->rd_rel->relkind == RELKIND_INDEX)
RelationReloadIndexInfo(rd);
else
RelationClearRelation(rd, true);
Assert(rd->rd_isvalid);
}
return rd;
}
/*
* no reldesc in the cache, so have RelationBuildDesc() build one and add
* it.
*/
rd = RelationBuildDesc(relationId, true);
if (RelationIsValid(rd))
RelationIncrementReferenceCount(rd);
return rd;
}
/* ----------------------------------------------------------------
* cache invalidation support routines
* ----------------------------------------------------------------
*/
/*
* RelationIncrementReferenceCount
* Increments relation reference count.
*
* Note: bootstrap mode has its own weird ideas about relation refcount
* behavior; we ought to fix it someday, but for now, just disable
* reference count ownership tracking in bootstrap mode.
*/
void
RelationIncrementReferenceCount(Relation rel)
{
ResourceOwnerEnlargeRelationRefs(CurrentResourceOwner);
rel->rd_refcnt += 1;
if (!IsBootstrapProcessingMode())
ResourceOwnerRememberRelationRef(CurrentResourceOwner, rel);
}
/*
* RelationDecrementReferenceCount
* Decrements relation reference count.
*/
void
RelationDecrementReferenceCount(Relation rel)
{
Assert(rel->rd_refcnt > 0);
rel->rd_refcnt -= 1;
if (!IsBootstrapProcessingMode())
ResourceOwnerForgetRelationRef(CurrentResourceOwner, rel);
}
/*
* RelationClose - close an open relation
*
* Actually, we just decrement the refcount.
*
* NOTE: if compiled with -DRELCACHE_FORCE_RELEASE then relcache entries
* will be freed as soon as their refcount goes to zero. In combination
* with aset.c's CLOBBER_FREED_MEMORY option, this provides a good test
* to catch references to already-released relcache entries. It slows
* things down quite a bit, however.
*/
void
RelationClose(Relation relation)
{
/* Note: no locking manipulations needed */
RelationDecrementReferenceCount(relation);
#ifdef RELCACHE_FORCE_RELEASE
if (RelationHasReferenceCountZero(relation) &&
relation->rd_createSubid == InvalidSubTransactionId &&
relation->rd_newRelfilenodeSubid == InvalidSubTransactionId)
RelationClearRelation(relation, false);
#endif
}
/*
* RelationReloadIndexInfo - reload minimal information for an open index
*
* This function is used only for indexes. A relcache inval on an index
* can mean that its pg_class or pg_index row changed. There are only
* very limited changes that are allowed to an existing index's schema,
* so we can update the relcache entry without a complete rebuild; which
* is fortunate because we can't rebuild an index entry that is "nailed"
* and/or in active use. We support full replacement of the pg_class row,
* as well as updates of a few simple fields of the pg_index row.
*
* We can't necessarily reread the catalog rows right away; we might be
* in a failed transaction when we receive the SI notification. If so,
* RelationClearRelation just marks the entry as invalid by setting
* rd_isvalid to false. This routine is called to fix the entry when it
* is next needed.
*
* We assume that at the time we are called, we have at least AccessShareLock
* on the target index. (Note: in the calls from RelationClearRelation,
* this is legitimate because we know the rel has positive refcount.)
*
* If the target index is an index on pg_class or pg_index, we'd better have
* previously gotten at least AccessShareLock on its underlying catalog,
* else we are at risk of deadlock against someone trying to exclusive-lock
* the heap and index in that order. This is ensured in current usage by
* only applying this to indexes being opened or having positive refcount.
*/
static void
RelationReloadIndexInfo(Relation relation)
{
bool indexOK;
HeapTuple pg_class_tuple;
Form_pg_class relp;
/* Should be called only for invalidated indexes */
Assert(relation->rd_rel->relkind == RELKIND_INDEX &&
!relation->rd_isvalid);
/* Ensure it's closed at smgr level */
RelationCloseSmgr(relation);
/* Must free any AM cached data upon relcache flush */
if (relation->rd_amcache)
pfree(relation->rd_amcache);
relation->rd_amcache = NULL;
/*
* If it's a shared index, we might be called before backend startup has
* finished selecting a database, in which case we have no way to read
* pg_class yet. However, a shared index can never have any significant
* schema updates, so it's okay to ignore the invalidation signal. Just
* mark it valid and return without doing anything more.
*/
if (relation->rd_rel->relisshared && !criticalRelcachesBuilt)
{
relation->rd_isvalid = true;
return;
}
/*
* Read the pg_class row
*
* Don't try to use an indexscan of pg_class_oid_index to reload the info
* for pg_class_oid_index ...
*/
indexOK = (RelationGetRelid(relation) != ClassOidIndexId);
pg_class_tuple = ScanPgRelation(RelationGetRelid(relation), indexOK, false);
if (!HeapTupleIsValid(pg_class_tuple))
elog(ERROR, "could not find pg_class tuple for index %u",
RelationGetRelid(relation));
relp = (Form_pg_class) GETSTRUCT(pg_class_tuple);
memcpy(relation->rd_rel, relp, CLASS_TUPLE_SIZE);
/* Reload reloptions in case they changed */
if (relation->rd_options)
pfree(relation->rd_options);
RelationParseRelOptions(relation, pg_class_tuple);
/* done with pg_class tuple */
heap_freetuple(pg_class_tuple);
/* We must recalculate physical address in case it changed */
RelationInitPhysicalAddr(relation);
/*
* For a non-system index, there are fields of the pg_index row that are
* allowed to change, so re-read that row and update the relcache entry.
* Most of the info derived from pg_index (such as support function lookup
* info) cannot change, and indeed the whole point of this routine is to
* update the relcache entry without clobbering that data; so wholesale
* replacement is not appropriate.
*/
if (!IsSystemRelation(relation))
{
HeapTuple tuple;
Form_pg_index index;
tuple = SearchSysCache1(INDEXRELID,
ObjectIdGetDatum(RelationGetRelid(relation)));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for index %u",
RelationGetRelid(relation));
index = (Form_pg_index) GETSTRUCT(tuple);
/*
* Basically, let's just copy all the bool fields. There are one or
* two of these that can't actually change in the current code, but
* it's not worth it to track exactly which ones they are. None of
* the array fields are allowed to change, though.
*/
relation->rd_index->indisunique = index->indisunique;
relation->rd_index->indisprimary = index->indisprimary;
relation->rd_index->indisexclusion = index->indisexclusion;
relation->rd_index->indimmediate = index->indimmediate;
relation->rd_index->indisclustered = index->indisclustered;
relation->rd_index->indisvalid = index->indisvalid;
relation->rd_index->indcheckxmin = index->indcheckxmin;
relation->rd_index->indisready = index->indisready;
relation->rd_index->indislive = index->indislive;
/* Copy xmin too, as that is needed to make sense of indcheckxmin */
HeapTupleHeaderSetXmin(relation->rd_indextuple->t_data,
HeapTupleHeaderGetXmin(tuple->t_data));
ReleaseSysCache(tuple);
}
/* Okay, now it's valid again */
relation->rd_isvalid = true;
}
/*
* RelationDestroyRelation
*
* Physically delete a relation cache entry and all subsidiary data.
* Caller must already have unhooked the entry from the hash table.
*/
static void
RelationDestroyRelation(Relation relation, bool remember_tupdesc)
{
Assert(RelationHasReferenceCountZero(relation));
/*
* Make sure smgr and lower levels close the relation's files, if they
* weren't closed already. (This was probably done by caller, but let's
* just be real sure.)
*/
RelationCloseSmgr(relation);
/*
* Free all the subsidiary data structures of the relcache entry, then the
* entry itself.
*/
if (relation->rd_rel)
pfree(relation->rd_rel);
/* can't use DecrTupleDescRefCount here */
Assert(relation->rd_att->tdrefcount > 0);
if (--relation->rd_att->tdrefcount == 0)
{
/*
* If we Rebuilt a relcache entry during a transaction then its
* possible we did that because the TupDesc changed as the result of
* an ALTER TABLE that ran at less than AccessExclusiveLock. It's
* possible someone copied that TupDesc, in which case the copy would
* point to free'd memory. So if we rebuild an entry we keep the
* TupDesc around until end of transaction, to be safe.
*/
if (remember_tupdesc)
RememberToFreeTupleDescAtEOX(relation->rd_att);
else
FreeTupleDesc(relation->rd_att);
}
FreeTriggerDesc(relation->trigdesc);
list_free_deep(relation->rd_fkeylist);
list_free(relation->rd_indexlist);
bms_free(relation->rd_indexattr);
bms_free(relation->rd_keyattr);
bms_free(relation->rd_pkattr);
bms_free(relation->rd_idattr);
if (relation->rd_pubactions)
pfree(relation->rd_pubactions);
if (relation->rd_options)
pfree(relation->rd_options);
if (relation->rd_indextuple)
pfree(relation->rd_indextuple);
if (relation->rd_indexcxt)
MemoryContextDelete(relation->rd_indexcxt);
if (relation->rd_rulescxt)
MemoryContextDelete(relation->rd_rulescxt);
if (relation->rd_rsdesc)
MemoryContextDelete(relation->rd_rsdesc->rscxt);
if (relation->rd_partkeycxt)
MemoryContextDelete(relation->rd_partkeycxt);
if (relation->rd_pdcxt)
MemoryContextDelete(relation->rd_pdcxt);
if (relation->rd_partcheck)
pfree(relation->rd_partcheck);
if (relation->rd_fdwroutine)
pfree(relation->rd_fdwroutine);
pfree(relation);
}
/*
* RelationClearRelation
*
* Physically blow away a relation cache entry, or reset it and rebuild
* it from scratch (that is, from catalog entries). The latter path is
* used when we are notified of a change to an open relation (one with
* refcount > 0).
*
* NB: when rebuilding, we'd better hold some lock on the relation,
* else the catalog data we need to read could be changing under us.
* Also, a rel to be rebuilt had better have refcnt > 0. This is because
* an sinval reset could happen while we're accessing the catalogs, and
* the rel would get blown away underneath us by RelationCacheInvalidate
* if it has zero refcnt.
*
* The "rebuild" parameter is redundant in current usage because it has
* to match the relation's refcnt status, but we keep it as a crosscheck
* that we're doing what the caller expects.
*/
static void
RelationClearRelation(Relation relation, bool rebuild)
{
/*
* As per notes above, a rel to be rebuilt MUST have refcnt > 0; while of
* course it would be an equally bad idea to blow away one with nonzero
* refcnt, since that would leave someone somewhere with a dangling
* pointer. All callers are expected to have verified that this holds.
*/
Assert(rebuild ?
!RelationHasReferenceCountZero(relation) :
RelationHasReferenceCountZero(relation));
/*
* Make sure smgr and lower levels close the relation's files, if they
* weren't closed already. If the relation is not getting deleted, the
* next smgr access should reopen the files automatically. This ensures
* that the low-level file access state is updated after, say, a vacuum
* truncation.
*/
RelationCloseSmgr(relation);
/*
* Never, never ever blow away a nailed-in system relation, because we'd
* be unable to recover. However, we must redo RelationInitPhysicalAddr
* in case it is a mapped relation whose mapping changed.
*
* If it's a nailed-but-not-mapped index, then we need to re-read the
* pg_class row to see if its relfilenode changed. We do that immediately
* if we're inside a valid transaction and the relation is open (not
* counting the nailed refcount). Otherwise just mark the entry as
* possibly invalid, and it'll be fixed when next opened.
*/
if (relation->rd_isnailed)
{
RelationInitPhysicalAddr(relation);
if (relation->rd_rel->relkind == RELKIND_INDEX)
{
relation->rd_isvalid = false; /* needs to be revalidated */
if (relation->rd_refcnt > 1 && IsTransactionState())
RelationReloadIndexInfo(relation);
}
return;
}
/*
* Even non-system indexes should not be blown away if they are open and
* have valid index support information. This avoids problems with active
* use of the index support information. As with nailed indexes, we
* re-read the pg_class row to handle possible physical relocation of the
* index, and we check for pg_index updates too.
*/
if (relation->rd_rel->relkind == RELKIND_INDEX &&
relation->rd_refcnt > 0 &&
relation->rd_indexcxt != NULL)
{
relation->rd_isvalid = false; /* needs to be revalidated */
if (IsTransactionState())
RelationReloadIndexInfo(relation);
return;
}
/* Mark it invalid until we've finished rebuild */
relation->rd_isvalid = false;
/*
* If we're really done with the relcache entry, blow it away. But if
* someone is still using it, reconstruct the whole deal without moving
* the physical RelationData record (so that the someone's pointer is
* still valid).
*/
if (!rebuild)
{
/* Remove it from the hash table */
RelationCacheDelete(relation);
/* And release storage */
RelationDestroyRelation(relation, false);
}
else if (!IsTransactionState())
{
/*
* If we're not inside a valid transaction, we can't do any catalog
* access so it's not possible to rebuild yet. Just exit, leaving
* rd_isvalid = false so that the rebuild will occur when the entry is
* next opened.
*
* Note: it's possible that we come here during subtransaction abort,
* and the reason for wanting to rebuild is that the rel is open in
* the outer transaction. In that case it might seem unsafe to not
* rebuild immediately, since whatever code has the rel already open
* will keep on using the relcache entry as-is. However, in such a
* case the outer transaction should be holding a lock that's
* sufficient to prevent any significant change in the rel's schema,
* so the existing entry contents should be good enough for its
* purposes; at worst we might be behind on statistics updates or the
* like. (See also CheckTableNotInUse() and its callers.) These same
* remarks also apply to the cases above where we exit without having
* done RelationReloadIndexInfo() yet.
*/
return;
}
else
{
/*
* Our strategy for rebuilding an open relcache entry is to build a
* new entry from scratch, swap its contents with the old entry, and
* finally delete the new entry (along with any infrastructure swapped
* over from the old entry). This is to avoid trouble in case an
* error causes us to lose control partway through. The old entry
* will still be marked !rd_isvalid, so we'll try to rebuild it again
* on next access. Meanwhile it's not any less valid than it was
* before, so any code that might expect to continue accessing it
* isn't hurt by the rebuild failure. (Consider for example a
* subtransaction that ALTERs a table and then gets canceled partway
* through the cache entry rebuild. The outer transaction should
* still see the not-modified cache entry as valid.) The worst
* consequence of an error is leaking the necessarily-unreferenced new
* entry, and this shouldn't happen often enough for that to be a big
* problem.
*
* When rebuilding an open relcache entry, we must preserve ref count,
* rd_createSubid/rd_newRelfilenodeSubid, and rd_toastoid state. Also
* attempt to preserve the pg_class entry (rd_rel), tupledesc,
* rewrite-rule, partition key, and partition descriptor substructures
* in place, because various places assume that these structures won't
* move while they are working with an open relcache entry. (Note:
* the refcount mechanism for tupledescs might someday allow us to
* remove this hack for the tupledesc.)
*
* Note that this process does not touch CurrentResourceOwner; which
* is good because whatever ref counts the entry may have do not
* necessarily belong to that resource owner.
*/
Relation newrel;
Oid save_relid = RelationGetRelid(relation);
bool keep_tupdesc;
bool keep_rules;
bool keep_policies;
bool keep_partkey;
bool keep_partdesc;
/* Build temporary entry, but don't link it into hashtable */
newrel = RelationBuildDesc(save_relid, false);
if (newrel == NULL)
{
/*
* We can validly get here, if we're using a historic snapshot in
* which a relation, accessed from outside logical decoding, is
* still invisible. In that case it's fine to just mark the
* relation as invalid and return - it'll fully get reloaded by
* the cache reset at the end of logical decoding (or at the next
* access). During normal processing we don't want to ignore this
* case as it shouldn't happen there, as explained below.
*/
if (HistoricSnapshotActive())
return;
/*
* This shouldn't happen as dropping a relation is intended to be
* impossible if still referenced (c.f. CheckTableNotInUse()). But
* if we get here anyway, we can't just delete the relcache entry,
* as it possibly could get accessed later (as e.g. the error
* might get trapped and handled via a subtransaction rollback).
*/
elog(ERROR, "relation %u deleted while still in use", save_relid);
}
keep_tupdesc = equalTupleDescs(relation->rd_att, newrel->rd_att);
keep_rules = equalRuleLocks(relation->rd_rules, newrel->rd_rules);
keep_policies = equalRSDesc(relation->rd_rsdesc, newrel->rd_rsdesc);
keep_partkey = (relation->rd_partkey != NULL);
keep_partdesc = equalPartitionDescs(relation->rd_partkey,
relation->rd_partdesc,
newrel->rd_partdesc);
/*
* Perform swapping of the relcache entry contents. Within this
* process the old entry is momentarily invalid, so there *must* be no
* possibility of CHECK_FOR_INTERRUPTS within this sequence. Do it in
* all-in-line code for safety.
*
* Since the vast majority of fields should be swapped, our method is
* to swap the whole structures and then re-swap those few fields we
* didn't want swapped.
*/
#define SWAPFIELD(fldtype, fldname) \
do { \
fldtype _tmp = newrel->fldname; \
newrel->fldname = relation->fldname; \
relation->fldname = _tmp; \
} while (0)
/* swap all Relation struct fields */
{
RelationData tmpstruct;
memcpy(&tmpstruct, newrel, sizeof(RelationData));
memcpy(newrel, relation, sizeof(RelationData));
memcpy(relation, &tmpstruct, sizeof(RelationData));
}
/* rd_smgr must not be swapped, due to back-links from smgr level */
SWAPFIELD(SMgrRelation, rd_smgr);
/* rd_refcnt must be preserved */
SWAPFIELD(int, rd_refcnt);
/* isnailed shouldn't change */
Assert(newrel->rd_isnailed == relation->rd_isnailed);
/* creation sub-XIDs must be preserved */
SWAPFIELD(SubTransactionId, rd_createSubid);
SWAPFIELD(SubTransactionId, rd_newRelfilenodeSubid);
/* un-swap rd_rel pointers, swap contents instead */
SWAPFIELD(Form_pg_class, rd_rel);
/* ... but actually, we don't have to update newrel->rd_rel */
memcpy(relation->rd_rel, newrel->rd_rel, CLASS_TUPLE_SIZE);
/* preserve old tupledesc and rules if no logical change */
if (keep_tupdesc)
SWAPFIELD(TupleDesc, rd_att);
if (keep_rules)
{
SWAPFIELD(RuleLock *, rd_rules);
SWAPFIELD(MemoryContext, rd_rulescxt);
}
if (keep_policies)
SWAPFIELD(RowSecurityDesc *, rd_rsdesc);
/* toast OID override must be preserved */
SWAPFIELD(Oid, rd_toastoid);
/* pgstat_info must be preserved */
SWAPFIELD(struct PgStat_TableStatus *, pgstat_info);
/* partition key must be preserved, if we have one */
if (keep_partkey)
{
SWAPFIELD(PartitionKey, rd_partkey);
SWAPFIELD(MemoryContext, rd_partkeycxt);
}
/* preserve old partdesc if no logical change */
if (keep_partdesc)
{
SWAPFIELD(PartitionDesc, rd_partdesc);
SWAPFIELD(MemoryContext, rd_pdcxt);
}
#undef SWAPFIELD
/* And now we can throw away the temporary entry */
RelationDestroyRelation(newrel, !keep_tupdesc);
}
}
/*
* RelationFlushRelation
*
* Rebuild the relation if it is open (refcount > 0), else blow it away.
* This is used when we receive a cache invalidation event for the rel.
*/
static void
RelationFlushRelation(Relation relation)
{
if (relation->rd_createSubid != InvalidSubTransactionId ||
relation->rd_newRelfilenodeSubid != InvalidSubTransactionId)
{
/*
* New relcache entries are always rebuilt, not flushed; else we'd
* forget the "new" status of the relation, which is a useful
* optimization to have. Ditto for the new-relfilenode status.
*
* The rel could have zero refcnt here, so temporarily increment the
* refcnt to ensure it's safe to rebuild it. We can assume that the
* current transaction has some lock on the rel already.
*/
RelationIncrementReferenceCount(relation);
RelationClearRelation(relation, true);
RelationDecrementReferenceCount(relation);
}
else
{
/*
* Pre-existing rels can be dropped from the relcache if not open.
*/
bool rebuild = !RelationHasReferenceCountZero(relation);
RelationClearRelation(relation, rebuild);
}
}
/*
* RelationForgetRelation - unconditionally remove a relcache entry
*
* External interface for destroying a relcache entry when we
* drop the relation.
*/
void
RelationForgetRelation(Oid rid)
{
Relation relation;
RelationIdCacheLookup(rid, relation);
if (!PointerIsValid(relation))
return; /* not in cache, nothing to do */
if (!RelationHasReferenceCountZero(relation))
elog(ERROR, "relation %u is still open", rid);
/* Unconditionally destroy the relcache entry */
RelationClearRelation(relation, false);
}
/*
* RelationCacheInvalidateEntry
*
* This routine is invoked for SI cache flush messages.
*
* Any relcache entry matching the relid must be flushed. (Note: caller has
* already determined that the relid belongs to our database or is a shared
* relation.)
*
* We used to skip local relations, on the grounds that they could
* not be targets of cross-backend SI update messages; but it seems
* safer to process them, so that our *own* SI update messages will
* have the same effects during CommandCounterIncrement for both
* local and nonlocal relations.
*/
void
RelationCacheInvalidateEntry(Oid relationId)
{
Relation relation;
RelationIdCacheLookup(relationId, relation);
if (PointerIsValid(relation))
{
relcacheInvalsReceived++;
RelationFlushRelation(relation);
}
}
/*
* RelationCacheInvalidate
* Blow away cached relation descriptors that have zero reference counts,
* and rebuild those with positive reference counts. Also reset the smgr
* relation cache and re-read relation mapping data.
*
* This is currently used only to recover from SI message buffer overflow,
* so we do not touch new-in-transaction relations; they cannot be targets
* of cross-backend SI updates (and our own updates now go through a
* separate linked list that isn't limited by the SI message buffer size).
* Likewise, we need not discard new-relfilenode-in-transaction hints,
* since any invalidation of those would be a local event.
*
* We do this in two phases: the first pass deletes deletable items, and
* the second one rebuilds the rebuildable items. This is essential for
* safety, because hash_seq_search only copes with concurrent deletion of
* the element it is currently visiting. If a second SI overflow were to
* occur while we are walking the table, resulting in recursive entry to
* this routine, we could crash because the inner invocation blows away
* the entry next to be visited by the outer scan. But this way is OK,
* because (a) during the first pass we won't process any more SI messages,
* so hash_seq_search will complete safely; (b) during the second pass we
* only hold onto pointers to nondeletable entries.
*
* The two-phase approach also makes it easy to update relfilenodes for
* mapped relations before we do anything else, and to ensure that the
* second pass processes nailed-in-cache items before other nondeletable
* items. This should ensure that system catalogs are up to date before
* we attempt to use them to reload information about other open relations.
*/
void
RelationCacheInvalidate(void)
{
HASH_SEQ_STATUS status;
RelIdCacheEnt *idhentry;
Relation relation;
List *rebuildFirstList = NIL;
List *rebuildList = NIL;
ListCell *l;
/*
* Reload relation mapping data before starting to reconstruct cache.
*/
RelationMapInvalidateAll();
/* Phase 1 */
hash_seq_init(&status, RelationIdCache);
while ((idhentry = (RelIdCacheEnt *) hash_seq_search(&status)) != NULL)
{
relation = idhentry->reldesc;
/* Must close all smgr references to avoid leaving dangling ptrs */
RelationCloseSmgr(relation);
/*
* Ignore new relations; no other backend will manipulate them before
* we commit. Likewise, before replacing a relation's relfilenode, we
* shall have acquired AccessExclusiveLock and drained any applicable
* pending invalidations.
*/
if (relation->rd_createSubid != InvalidSubTransactionId ||
relation->rd_newRelfilenodeSubid != InvalidSubTransactionId)
continue;
relcacheInvalsReceived++;
if (RelationHasReferenceCountZero(relation))
{
/* Delete this entry immediately */
Assert(!relation->rd_isnailed);
RelationClearRelation(relation, false);
}
else
{
/*
* If it's a mapped relation, immediately update its rd_node in
* case its relfilenode changed. We must do this during phase 1
* in case the relation is consulted during rebuild of other
* relcache entries in phase 2. It's safe since consulting the
* map doesn't involve any access to relcache entries.
*/
if (RelationIsMapped(relation))
RelationInitPhysicalAddr(relation);
/*
* Add this entry to list of stuff to rebuild in second pass.
* pg_class goes to the front of rebuildFirstList while
* pg_class_oid_index goes to the back of rebuildFirstList, so
* they are done first and second respectively. Other nailed
* relations go to the front of rebuildList, so they'll be done
* next in no particular order; and everything else goes to the
* back of rebuildList.
*/
if (RelationGetRelid(relation) == RelationRelationId)
rebuildFirstList = lcons(relation, rebuildFirstList);
else if (RelationGetRelid(relation) == ClassOidIndexId)
rebuildFirstList = lappend(rebuildFirstList, relation);
else if (relation->rd_isnailed)
rebuildList = lcons(relation, rebuildList);
else
rebuildList = lappend(rebuildList, relation);
}
}
/*
* Now zap any remaining smgr cache entries. This must happen before we
* start to rebuild entries, since that may involve catalog fetches which
* will re-open catalog files.
*/
smgrcloseall();
/* Phase 2: rebuild the items found to need rebuild in phase 1 */
foreach(l, rebuildFirstList)
{
relation = (Relation) lfirst(l);
RelationClearRelation(relation, true);
}
list_free(rebuildFirstList);
foreach(l, rebuildList)
{
relation = (Relation) lfirst(l);
RelationClearRelation(relation, true);
}
list_free(rebuildList);
}
/*
* RelationCloseSmgrByOid - close a relcache entry's smgr link
*
* Needed in some cases where we are changing a relation's physical mapping.
* The link will be automatically reopened on next use.
*/
void
RelationCloseSmgrByOid(Oid relationId)
{
Relation relation;
RelationIdCacheLookup(relationId, relation);
if (!PointerIsValid(relation))
return; /* not in cache, nothing to do */
RelationCloseSmgr(relation);
}
static void
RememberToFreeTupleDescAtEOX(TupleDesc td)
{
if (EOXactTupleDescArray == NULL)
{
MemoryContext oldcxt;
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
EOXactTupleDescArray = (TupleDesc *) palloc(16 * sizeof(TupleDesc));
EOXactTupleDescArrayLen = 16;
NextEOXactTupleDescNum = 0;
MemoryContextSwitchTo(oldcxt);
}
else if (NextEOXactTupleDescNum >= EOXactTupleDescArrayLen)
{
int32 newlen = EOXactTupleDescArrayLen * 2;
Assert(EOXactTupleDescArrayLen > 0);
EOXactTupleDescArray = (TupleDesc *) repalloc(EOXactTupleDescArray,
newlen * sizeof(TupleDesc));
EOXactTupleDescArrayLen = newlen;
}
EOXactTupleDescArray[NextEOXactTupleDescNum++] = td;
}
/*
* AtEOXact_RelationCache
*
* Clean up the relcache at main-transaction commit or abort.
*
* Note: this must be called *before* processing invalidation messages.
* In the case of abort, we don't want to try to rebuild any invalidated
* cache entries (since we can't safely do database accesses). Therefore
* we must reset refcnts before handling pending invalidations.
*
* As of PostgreSQL 8.1, relcache refcnts should get released by the
* ResourceOwner mechanism. This routine just does a debugging
* cross-check that no pins remain. However, we also need to do special
* cleanup when the current transaction created any relations or made use
* of forced index lists.
*/
void
AtEOXact_RelationCache(bool isCommit)
{
HASH_SEQ_STATUS status;
RelIdCacheEnt *idhentry;
int i;
/*
* Unless the eoxact_list[] overflowed, we only need to examine the rels
* listed in it. Otherwise fall back on a hash_seq_search scan.
*
* For simplicity, eoxact_list[] entries are not deleted till end of
* top-level transaction, even though we could remove them at
* subtransaction end in some cases, or remove relations from the list if
* they are cleared for other reasons. Therefore we should expect the
* case that list entries are not found in the hashtable; if not, there's
* nothing to do for them.
*/
if (eoxact_list_overflowed)
{
hash_seq_init(&status, RelationIdCache);
while ((idhentry = (RelIdCacheEnt *) hash_seq_search(&status)) != NULL)
{
AtEOXact_cleanup(idhentry->reldesc, isCommit);
}
}
else
{
for (i = 0; i < eoxact_list_len; i++)
{
idhentry = (RelIdCacheEnt *) hash_search(RelationIdCache,
(void *) &eoxact_list[i],
HASH_FIND,
NULL);
if (idhentry != NULL)
AtEOXact_cleanup(idhentry->reldesc, isCommit);
}
}
if (EOXactTupleDescArrayLen > 0)
{
Assert(EOXactTupleDescArray != NULL);
for (i = 0; i < NextEOXactTupleDescNum; i++)
FreeTupleDesc(EOXactTupleDescArray[i]);
pfree(EOXactTupleDescArray);
EOXactTupleDescArray = NULL;
}
/* Now we're out of the transaction and can clear the lists */
eoxact_list_len = 0;
eoxact_list_overflowed = false;
NextEOXactTupleDescNum = 0;
EOXactTupleDescArrayLen = 0;
}
/*
* AtEOXact_cleanup
*
* Clean up a single rel at main-transaction commit or abort
*
* NB: this processing must be idempotent, because EOXactListAdd() doesn't
* bother to prevent duplicate entries in eoxact_list[].
*/
static void
AtEOXact_cleanup(Relation relation, bool isCommit)
{
/*
* The relcache entry's ref count should be back to its normal
* not-in-a-transaction state: 0 unless it's nailed in cache.
*
* In bootstrap mode, this is NOT true, so don't check it --- the
* bootstrap code expects relations to stay open across start/commit
* transaction calls. (That seems bogus, but it's not worth fixing.)
*
* Note: ideally this check would be applied to every relcache entry, not
* just those that have eoxact work to do. But it's not worth forcing a
* scan of the whole relcache just for this. (Moreover, doing so would
* mean that assert-enabled testing never tests the hash_search code path
* above, which seems a bad idea.)
*/
#ifdef USE_ASSERT_CHECKING
if (!IsBootstrapProcessingMode())
{
int expected_refcnt;
expected_refcnt = relation->rd_isnailed ? 1 : 0;
Assert(relation->rd_refcnt == expected_refcnt);
}
#endif
/*
* Is it a relation created in the current transaction?
*
* During commit, reset the flag to zero, since we are now out of the
* creating transaction. During abort, simply delete the relcache entry
* --- it isn't interesting any longer. (NOTE: if we have forgotten the
* new-ness of a new relation due to a forced cache flush, the entry will
* get deleted anyway by shared-cache-inval processing of the aborted
* pg_class insertion.)
*/
if (relation->rd_createSubid != InvalidSubTransactionId)
{
if (isCommit)
relation->rd_createSubid = InvalidSubTransactionId;
else if (RelationHasReferenceCountZero(relation))
{
RelationClearRelation(relation, false);
return;
}
else
{
/*
* Hmm, somewhere there's a (leaked?) reference to the relation.
* We daren't remove the entry for fear of dereferencing a
* dangling pointer later. Bleat, and mark it as not belonging to
* the current transaction. Hopefully it'll get cleaned up
* eventually. This must be just a WARNING to avoid
* error-during-error-recovery loops.
*/
relation->rd_createSubid = InvalidSubTransactionId;
elog(WARNING, "cannot remove relcache entry for \"%s\" because it has nonzero refcount",
RelationGetRelationName(relation));
}
}
/*
* Likewise, reset the hint about the relfilenode being new.
*/
relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
/*
* Flush any temporary index list.
*/
if (relation->rd_indexvalid == 2)
{
list_free(relation->rd_indexlist);
relation->rd_indexlist = NIL;
relation->rd_oidindex = InvalidOid;
relation->rd_pkindex = InvalidOid;
relation->rd_replidindex = InvalidOid;
relation->rd_indexvalid = 0;
}
}
/*
* AtEOSubXact_RelationCache
*
* Clean up the relcache at sub-transaction commit or abort.
*
* Note: this must be called *before* processing invalidation messages.
*/
void
AtEOSubXact_RelationCache(bool isCommit, SubTransactionId mySubid,
SubTransactionId parentSubid)
{
HASH_SEQ_STATUS status;
RelIdCacheEnt *idhentry;
int i;
/*
* Unless the eoxact_list[] overflowed, we only need to examine the rels
* listed in it. Otherwise fall back on a hash_seq_search scan. Same
* logic as in AtEOXact_RelationCache.
*/
if (eoxact_list_overflowed)
{
hash_seq_init(&status, RelationIdCache);
while ((idhentry = (RelIdCacheEnt *) hash_seq_search(&status)) != NULL)
{
AtEOSubXact_cleanup(idhentry->reldesc, isCommit,
mySubid, parentSubid);
}
}
else
{
for (i = 0; i < eoxact_list_len; i++)
{
idhentry = (RelIdCacheEnt *) hash_search(RelationIdCache,
(void *) &eoxact_list[i],
HASH_FIND,
NULL);
if (idhentry != NULL)
AtEOSubXact_cleanup(idhentry->reldesc, isCommit,
mySubid, parentSubid);
}
}
/* Don't reset the list; we still need more cleanup later */
}
/*
* AtEOSubXact_cleanup
*
* Clean up a single rel at subtransaction commit or abort
*
* NB: this processing must be idempotent, because EOXactListAdd() doesn't
* bother to prevent duplicate entries in eoxact_list[].
*/
static void
AtEOSubXact_cleanup(Relation relation, bool isCommit,
SubTransactionId mySubid, SubTransactionId parentSubid)
{
/*
* Is it a relation created in the current subtransaction?
*
* During subcommit, mark it as belonging to the parent, instead. During
* subabort, simply delete the relcache entry.
*/
if (relation->rd_createSubid == mySubid)
{
if (isCommit)
relation->rd_createSubid = parentSubid;
else if (RelationHasReferenceCountZero(relation))
{
RelationClearRelation(relation, false);
return;
}
else
{
/*
* Hmm, somewhere there's a (leaked?) reference to the relation.
* We daren't remove the entry for fear of dereferencing a
* dangling pointer later. Bleat, and transfer it to the parent
* subtransaction so we can try again later. This must be just a
* WARNING to avoid error-during-error-recovery loops.
*/
relation->rd_createSubid = parentSubid;
elog(WARNING, "cannot remove relcache entry for \"%s\" because it has nonzero refcount",
RelationGetRelationName(relation));
}
}
/*
* Likewise, update or drop any new-relfilenode-in-subtransaction hint.
*/
if (relation->rd_newRelfilenodeSubid == mySubid)
{
if (isCommit)
relation->rd_newRelfilenodeSubid = parentSubid;
else
relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
}
/*
* Flush any temporary index list.
*/
if (relation->rd_indexvalid == 2)
{
list_free(relation->rd_indexlist);
relation->rd_indexlist = NIL;
relation->rd_oidindex = InvalidOid;
relation->rd_pkindex = InvalidOid;
relation->rd_replidindex = InvalidOid;
relation->rd_indexvalid = 0;
}
}
/*
* RelationBuildLocalRelation
* Build a relcache entry for an about-to-be-created relation,
* and enter it into the relcache.
*/
Relation
RelationBuildLocalRelation(const char *relname,
Oid relnamespace,
TupleDesc tupDesc,
Oid relid,
Oid relfilenode,
Oid reltablespace,
bool shared_relation,
bool mapped_relation,
char relpersistence,
char relkind)
{
Relation rel;
MemoryContext oldcxt;
int natts = tupDesc->natts;
int i;
bool has_not_null;
bool nailit;
AssertArg(natts >= 0);
/*
* check for creation of a rel that must be nailed in cache.
*
* XXX this list had better match the relations specially handled in
* RelationCacheInitializePhase2/3.
*/
switch (relid)
{
case DatabaseRelationId:
case AuthIdRelationId:
case AuthMemRelationId:
case RelationRelationId:
case AttributeRelationId:
case ProcedureRelationId:
case TypeRelationId:
nailit = true;
break;
default:
nailit = false;
break;
}
/*
* check that hardwired list of shared rels matches what's in the
* bootstrap .bki file. If you get a failure here during initdb, you
* probably need to fix IsSharedRelation() to match whatever you've done
* to the set of shared relations.
*/
if (shared_relation != IsSharedRelation(relid))
elog(ERROR, "shared_relation flag for \"%s\" does not match IsSharedRelation(%u)",
relname, relid);
/* Shared relations had better be mapped, too */
Assert(mapped_relation || !shared_relation);
/*
* switch to the cache context to create the relcache entry.
*/
if (!CacheMemoryContext)
CreateCacheMemoryContext();
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
/*
* allocate a new relation descriptor and fill in basic state fields.
*/
rel = (Relation) palloc0(sizeof(RelationData));
/* make sure relation is marked as having no open file yet */
rel->rd_smgr = NULL;
/* mark it nailed if appropriate */
rel->rd_isnailed = nailit;
rel->rd_refcnt = nailit ? 1 : 0;
/* it's being created in this transaction */
rel->rd_createSubid = GetCurrentSubTransactionId();
rel->rd_newRelfilenodeSubid = InvalidSubTransactionId;
/*
* create a new tuple descriptor from the one passed in. We do this
* partly to copy it into the cache context, and partly because the new
* relation can't have any defaults or constraints yet; they have to be
* added in later steps, because they require additions to multiple system
* catalogs. We can copy attnotnull constraints here, however.
*/
rel->rd_att = CreateTupleDescCopy(tupDesc);
rel->rd_att->tdrefcount = 1; /* mark as refcounted */
has_not_null = false;
for (i = 0; i < natts; i++)
{
Form_pg_attribute satt = TupleDescAttr(tupDesc, i);
Form_pg_attribute datt = TupleDescAttr(rel->rd_att, i);
datt->attidentity = satt->attidentity;
datt->attnotnull = satt->attnotnull;
has_not_null |= satt->attnotnull;
}
if (has_not_null)
{
TupleConstr *constr = (TupleConstr *) palloc0(sizeof(TupleConstr));
constr->has_not_null = true;
rel->rd_att->constr = constr;
}
/*
* initialize relation tuple form (caller may add/override data later)
*/
rel->rd_rel = (Form_pg_class) palloc0(CLASS_TUPLE_SIZE);
namestrcpy(&rel->rd_rel->relname, relname);
rel->rd_rel->relnamespace = relnamespace;
rel->rd_rel->relkind = relkind;
rel->rd_rel->relhasoids = rel->rd_att->tdhasoid;
rel->rd_rel->relnatts = natts;
rel->rd_rel->reltype = InvalidOid;
/* needed when bootstrapping: */
rel->rd_rel->relowner = BOOTSTRAP_SUPERUSERID;
/* set up persistence and relcache fields dependent on it */
rel->rd_rel->relpersistence = relpersistence;
switch (relpersistence)
{
case RELPERSISTENCE_UNLOGGED:
case RELPERSISTENCE_PERMANENT:
rel->rd_backend = InvalidBackendId;
rel->rd_islocaltemp = false;
break;
case RELPERSISTENCE_TEMP:
Assert(isTempOrTempToastNamespace(relnamespace));
rel->rd_backend = BackendIdForTempRelations();
rel->rd_islocaltemp = true;
break;
default:
elog(ERROR, "invalid relpersistence: %c", relpersistence);
break;
}
/* if it's a materialized view, it's not populated initially */
if (relkind == RELKIND_MATVIEW)
rel->rd_rel->relispopulated = false;
else
rel->rd_rel->relispopulated = true;
/* system relations and non-table objects don't have one */
if (!IsSystemNamespace(relnamespace) &&
(relkind == RELKIND_RELATION ||
relkind == RELKIND_MATVIEW ||
relkind == RELKIND_PARTITIONED_TABLE))
rel->rd_rel->relreplident = REPLICA_IDENTITY_DEFAULT;
else
rel->rd_rel->relreplident = REPLICA_IDENTITY_NOTHING;
/*
* Insert relation physical and logical identifiers (OIDs) into the right
* places. For a mapped relation, we set relfilenode to zero and rely on
* RelationInitPhysicalAddr to consult the map.
*/
rel->rd_rel->relisshared = shared_relation;
RelationGetRelid(rel) = relid;
for (i = 0; i < natts; i++)
TupleDescAttr(rel->rd_att, i)->attrelid = relid;
rel->rd_rel->reltablespace = reltablespace;
if (mapped_relation)
{
rel->rd_rel->relfilenode = InvalidOid;
/* Add it to the active mapping information */
RelationMapUpdateMap(relid, relfilenode, shared_relation, true);
}
else
rel->rd_rel->relfilenode = relfilenode;
RelationInitLockInfo(rel); /* see lmgr.c */
RelationInitPhysicalAddr(rel);
/*
* Okay to insert into the relcache hash table.
*
* Ordinarily, there should certainly not be an existing hash entry for
* the same OID; but during bootstrap, when we create a "real" relcache
* entry for one of the bootstrap relations, we'll be overwriting the
* phony one created with formrdesc. So allow that to happen for nailed
* rels.
*/
RelationCacheInsert(rel, nailit);
/*
* Flag relation as needing eoxact cleanup (to clear rd_createSubid). We
* can't do this before storing relid in it.
*/
EOXactListAdd(rel);
/*
* done building relcache entry.
*/
MemoryContextSwitchTo(oldcxt);
/* It's fully valid */
rel->rd_isvalid = true;
/*
* Caller expects us to pin the returned entry.
*/
RelationIncrementReferenceCount(rel);
return rel;
}
/*
* RelationSetNewRelfilenode
*
* Assign a new relfilenode (physical file name) to the relation.
*
* This allows a full rewrite of the relation to be done with transactional
* safety (since the filenode assignment can be rolled back). Note however
* that there is no simple way to access the relation's old data for the
* remainder of the current transaction. This limits the usefulness to cases
* such as TRUNCATE or rebuilding an index from scratch.
*
* Caller must already hold exclusive lock on the relation.
*
* The relation is marked with relfrozenxid = freezeXid (InvalidTransactionId
* must be passed for indexes and sequences). This should be a lower bound on
* the XIDs that will be put into the new relation contents.
*
* The new filenode's persistence is set to the given value. This is useful
* for the cases that are changing the relation's persistence; other callers
* need to pass the original relpersistence value.
*/
void
RelationSetNewRelfilenode(Relation relation, char persistence,
TransactionId freezeXid, MultiXactId minmulti)
{
Oid newrelfilenode;
RelFileNodeBackend newrnode;
Relation pg_class;
HeapTuple tuple;
Form_pg_class classform;
/* Indexes, sequences must have Invalid frozenxid; other rels must not */
Assert((relation->rd_rel->relkind == RELKIND_INDEX ||
relation->rd_rel->relkind == RELKIND_SEQUENCE) ?
freezeXid == InvalidTransactionId :
TransactionIdIsNormal(freezeXid));
Assert(TransactionIdIsNormal(freezeXid) == MultiXactIdIsValid(minmulti));
/* Allocate a new relfilenode */
newrelfilenode = GetNewRelFileNode(relation->rd_rel->reltablespace, NULL,
persistence);
/*
* Get a writable copy of the pg_class tuple for the given relation.
*/
pg_class = heap_open(RelationRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopy1(RELOID,
ObjectIdGetDatum(RelationGetRelid(relation)));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "could not find tuple for relation %u",
RelationGetRelid(relation));
classform = (Form_pg_class) GETSTRUCT(tuple);
/*
* Create storage for the main fork of the new relfilenode.
*
* NOTE: any conflict in relfilenode value will be caught here, if
* GetNewRelFileNode messes up for any reason.
*/
newrnode.node = relation->rd_node;
newrnode.node.relNode = newrelfilenode;
newrnode.backend = relation->rd_backend;
RelationCreateStorage(newrnode.node, persistence);
smgrclosenode(newrnode);
/*
* Schedule unlinking of the old storage at transaction commit.
*/
RelationDropStorage(relation);
/*
* Now update the pg_class row. However, if we're dealing with a mapped
* index, pg_class.relfilenode doesn't change; instead we have to send the
* update to the relation mapper.
*/
if (RelationIsMapped(relation))
RelationMapUpdateMap(RelationGetRelid(relation),
newrelfilenode,
relation->rd_rel->relisshared,
false);
else
classform->relfilenode = newrelfilenode;
/* These changes are safe even for a mapped relation */
if (relation->rd_rel->relkind != RELKIND_SEQUENCE)
{
classform->relpages = 0; /* it's empty until further notice */
classform->reltuples = 0;
classform->relallvisible = 0;
}
classform->relfrozenxid = freezeXid;
classform->relminmxid = minmulti;
classform->relpersistence = persistence;
CatalogTupleUpdate(pg_class, &tuple->t_self, tuple);
heap_freetuple(tuple);
heap_close(pg_class, RowExclusiveLock);
/*
* Make the pg_class row change visible, as well as the relation map
* change if any. This will cause the relcache entry to get updated, too.
*/
CommandCounterIncrement();
/*
* Mark the rel as having been given a new relfilenode in the current
* (sub) transaction. This is a hint that can be used to optimize later
* operations on the rel in the same transaction.
*/
relation->rd_newRelfilenodeSubid = GetCurrentSubTransactionId();
/* Flag relation as needing eoxact cleanup (to remove the hint) */
EOXactListAdd(relation);
}
/*
* RelationCacheInitialize
*
* This initializes the relation descriptor cache. At the time
* that this is invoked, we can't do database access yet (mainly
* because the transaction subsystem is not up); all we are doing
* is making an empty cache hashtable. This must be done before
* starting the initialization transaction, because otherwise
* AtEOXact_RelationCache would crash if that transaction aborts
* before we can get the relcache set up.
*/
#define INITRELCACHESIZE 400
void
RelationCacheInitialize(void)
{
HASHCTL ctl;
/*
* make sure cache memory context exists
*/
if (!CacheMemoryContext)
CreateCacheMemoryContext();
/*
* create hashtable that indexes the relcache
*/
MemSet(&ctl, 0, sizeof(ctl));
ctl.keysize = sizeof(Oid);
ctl.entrysize = sizeof(RelIdCacheEnt);
RelationIdCache = hash_create("Relcache by OID", INITRELCACHESIZE,
&ctl, HASH_ELEM | HASH_BLOBS);
/*
* relation mapper needs to be initialized too
*/
RelationMapInitialize();
}
/*
* RelationCacheInitializePhase2
*
* This is called to prepare for access to shared catalogs during startup.
* We must at least set up nailed reldescs for pg_database, pg_authid,
* pg_auth_members, and pg_shseclabel. Ideally we'd like to have reldescs
* for their indexes, too. We attempt to load this information from the
* shared relcache init file. If that's missing or broken, just make
* phony entries for the catalogs themselves.
* RelationCacheInitializePhase3 will clean up as needed.
*/
void
RelationCacheInitializePhase2(void)
{
MemoryContext oldcxt;
/*
* relation mapper needs initialized too
*/
RelationMapInitializePhase2();
/*
* In bootstrap mode, the shared catalogs aren't there yet anyway, so do
* nothing.
*/
if (IsBootstrapProcessingMode())
return;
/*
* switch to cache memory context
*/
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
/*
* Try to load the shared relcache cache file. If unsuccessful, bootstrap
* the cache with pre-made descriptors for the critical shared catalogs.
*/
if (!load_relcache_init_file(true))
{
formrdesc("pg_database", DatabaseRelation_Rowtype_Id, true,
true, Natts_pg_database, Desc_pg_database);
formrdesc("pg_authid", AuthIdRelation_Rowtype_Id, true,
true, Natts_pg_authid, Desc_pg_authid);
formrdesc("pg_auth_members", AuthMemRelation_Rowtype_Id, true,
false, Natts_pg_auth_members, Desc_pg_auth_members);
formrdesc("pg_shseclabel", SharedSecLabelRelation_Rowtype_Id, true,
false, Natts_pg_shseclabel, Desc_pg_shseclabel);
formrdesc("pg_subscription", SubscriptionRelation_Rowtype_Id, true,
true, Natts_pg_subscription, Desc_pg_subscription);
#define NUM_CRITICAL_SHARED_RELS 5 /* fix if you change list above */
}
MemoryContextSwitchTo(oldcxt);
}
/*
* RelationCacheInitializePhase3
*
* This is called as soon as the catcache and transaction system
* are functional and we have determined MyDatabaseId. At this point
* we can actually read data from the database's system catalogs.
* We first try to read pre-computed relcache entries from the local
* relcache init file. If that's missing or broken, make phony entries
* for the minimum set of nailed-in-cache relations. Then (unless
* bootstrapping) make sure we have entries for the critical system
* indexes. Once we've done all this, we have enough infrastructure to
* open any system catalog or use any catcache. The last step is to
* rewrite the cache files if needed.
*/
void
RelationCacheInitializePhase3(void)
{
HASH_SEQ_STATUS status;
RelIdCacheEnt *idhentry;
MemoryContext oldcxt;
bool needNewCacheFile = !criticalSharedRelcachesBuilt;
/*
* relation mapper needs initialized too
*/
RelationMapInitializePhase3();
/*
* switch to cache memory context
*/
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
/*
* Try to load the local relcache cache file. If unsuccessful, bootstrap
* the cache with pre-made descriptors for the critical "nailed-in" system
* catalogs.
*/
if (IsBootstrapProcessingMode() ||
!load_relcache_init_file(false))
{
needNewCacheFile = true;
formrdesc("pg_class", RelationRelation_Rowtype_Id, false,
true, Natts_pg_class, Desc_pg_class);
formrdesc("pg_attribute", AttributeRelation_Rowtype_Id, false,
false, Natts_pg_attribute, Desc_pg_attribute);
formrdesc("pg_proc", ProcedureRelation_Rowtype_Id, false,
true, Natts_pg_proc, Desc_pg_proc);
formrdesc("pg_type", TypeRelation_Rowtype_Id, false,
true, Natts_pg_type, Desc_pg_type);
#define NUM_CRITICAL_LOCAL_RELS 4 /* fix if you change list above */
}
MemoryContextSwitchTo(oldcxt);
/* In bootstrap mode, the faked-up formrdesc info is all we'll have */
if (IsBootstrapProcessingMode())
return;
/*
* If we didn't get the critical system indexes loaded into relcache, do
* so now. These are critical because the catcache and/or opclass cache
* depend on them for fetches done during relcache load. Thus, we have an
* infinite-recursion problem. We can break the recursion by doing
* heapscans instead of indexscans at certain key spots. To avoid hobbling
* performance, we only want to do that until we have the critical indexes
* loaded into relcache. Thus, the flag criticalRelcachesBuilt is used to
* decide whether to do heapscan or indexscan at the key spots, and we set
* it true after we've loaded the critical indexes.
*
* The critical indexes are marked as "nailed in cache", partly to make it
* easy for load_relcache_init_file to count them, but mainly because we
* cannot flush and rebuild them once we've set criticalRelcachesBuilt to
* true. (NOTE: perhaps it would be possible to reload them by
* temporarily setting criticalRelcachesBuilt to false again. For now,
* though, we just nail 'em in.)
*
* RewriteRelRulenameIndexId and TriggerRelidNameIndexId are not critical
* in the same way as the others, because the critical catalogs don't
* (currently) have any rules or triggers, and so these indexes can be
* rebuilt without inducing recursion. However they are used during
* relcache load when a rel does have rules or triggers, so we choose to
* nail them for performance reasons.
*/
if (!criticalRelcachesBuilt)
{
load_critical_index(ClassOidIndexId,
RelationRelationId);
load_critical_index(AttributeRelidNumIndexId,
AttributeRelationId);
load_critical_index(IndexRelidIndexId,
IndexRelationId);
load_critical_index(OpclassOidIndexId,
OperatorClassRelationId);
load_critical_index(AccessMethodProcedureIndexId,
AccessMethodProcedureRelationId);
load_critical_index(RewriteRelRulenameIndexId,
RewriteRelationId);
load_critical_index(TriggerRelidNameIndexId,
TriggerRelationId);
#define NUM_CRITICAL_LOCAL_INDEXES 7 /* fix if you change list above */
criticalRelcachesBuilt = true;
}
/*
* Process critical shared indexes too.
*
* DatabaseNameIndexId isn't critical for relcache loading, but rather for
* initial lookup of MyDatabaseId, without which we'll never find any
* non-shared catalogs at all. Autovacuum calls InitPostgres with a
* database OID, so it instead depends on DatabaseOidIndexId. We also
* need to nail up some indexes on pg_authid and pg_auth_members for use
* during client authentication. SharedSecLabelObjectIndexId isn't
* critical for the core system, but authentication hooks might be
* interested in it.
*/
if (!criticalSharedRelcachesBuilt)
{
load_critical_index(DatabaseNameIndexId,
DatabaseRelationId);
load_critical_index(DatabaseOidIndexId,
DatabaseRelationId);
load_critical_index(AuthIdRolnameIndexId,
AuthIdRelationId);
load_critical_index(AuthIdOidIndexId,
AuthIdRelationId);
load_critical_index(AuthMemMemRoleIndexId,
AuthMemRelationId);
load_critical_index(SharedSecLabelObjectIndexId,
SharedSecLabelRelationId);
#define NUM_CRITICAL_SHARED_INDEXES 6 /* fix if you change list above */
criticalSharedRelcachesBuilt = true;
}
/*
* Now, scan all the relcache entries and update anything that might be
* wrong in the results from formrdesc or the relcache cache file. If we
* faked up relcache entries using formrdesc, then read the real pg_class
* rows and replace the fake entries with them. Also, if any of the
* relcache entries have rules, triggers, or security policies, load that
* info the hard way since it isn't recorded in the cache file.
*
* Whenever we access the catalogs to read data, there is a possibility of
* a shared-inval cache flush causing relcache entries to be removed.
* Since hash_seq_search only guarantees to still work after the *current*
* entry is removed, it's unsafe to continue the hashtable scan afterward.
* We handle this by restarting the scan from scratch after each access.
* This is theoretically O(N^2), but the number of entries that actually
* need to be fixed is small enough that it doesn't matter.
*/
hash_seq_init(&status, RelationIdCache);
while ((idhentry = (RelIdCacheEnt *) hash_seq_search(&status)) != NULL)
{
Relation relation = idhentry->reldesc;
bool restart = false;
/*
* Make sure *this* entry doesn't get flushed while we work with it.
*/
RelationIncrementReferenceCount(relation);
/*
* If it's a faked-up entry, read the real pg_class tuple.
*/
if (relation->rd_rel->relowner == InvalidOid)
{
HeapTuple htup;
Form_pg_class relp;
htup = SearchSysCache1(RELOID,
ObjectIdGetDatum(RelationGetRelid(relation)));
if (!HeapTupleIsValid(htup))
elog(FATAL, "cache lookup failed for relation %u",
RelationGetRelid(relation));
relp = (Form_pg_class) GETSTRUCT(htup);
/*
* Copy tuple to relation->rd_rel. (See notes in
* AllocateRelationDesc())
*/
memcpy((char *) relation->rd_rel, (char *) relp, CLASS_TUPLE_SIZE);
/* Update rd_options while we have the tuple */
if (relation->rd_options)
pfree(relation->rd_options);
RelationParseRelOptions(relation, htup);
/*
* Check the values in rd_att were set up correctly. (We cannot
* just copy them over now: formrdesc must have set up the rd_att
* data correctly to start with, because it may already have been
* copied into one or more catcache entries.)
*/
Assert(relation->rd_att->tdtypeid == relp->reltype);
Assert(relation->rd_att->tdtypmod == -1);
Assert(relation->rd_att->tdhasoid == relp->relhasoids);
ReleaseSysCache(htup);
/* relowner had better be OK now, else we'll loop forever */
if (relation->rd_rel->relowner == InvalidOid)
elog(ERROR, "invalid relowner in pg_class entry for \"%s\"",
RelationGetRelationName(relation));
restart = true;
}
/*
* Fix data that isn't saved in relcache cache file.
*
* relhasrules or relhastriggers could possibly be wrong or out of
* date. If we don't actually find any rules or triggers, clear the
* local copy of the flag so that we don't get into an infinite loop
* here. We don't make any attempt to fix the pg_class entry, though.
*/
if (relation->rd_rel->relhasrules && relation->rd_rules == NULL)
{
RelationBuildRuleLock(relation);
if (relation->rd_rules == NULL)
relation->rd_rel->relhasrules = false;
restart = true;
}
if (relation->rd_rel->relhastriggers && relation->trigdesc == NULL)
{
RelationBuildTriggers(relation);
if (relation->trigdesc == NULL)
relation->rd_rel->relhastriggers = false;
restart = true;
}
/*
* Re-load the row security policies if the relation has them, since
* they are not preserved in the cache. Note that we can never NOT
* have a policy while relrowsecurity is true,
* RelationBuildRowSecurity will create a single default-deny policy
* if there is no policy defined in pg_policy.
*/
if (relation->rd_rel->relrowsecurity && relation->rd_rsdesc == NULL)
{
RelationBuildRowSecurity(relation);
Assert(relation->rd_rsdesc != NULL);
restart = true;
}
/*
* Reload the partition key and descriptor for a partitioned table.
*/
if (relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE &&
relation->rd_partkey == NULL)
{
RelationBuildPartitionKey(relation);
Assert(relation->rd_partkey != NULL);
restart = true;
}
if (relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE &&
relation->rd_partdesc == NULL)
{
RelationBuildPartitionDesc(relation);
Assert(relation->rd_partdesc != NULL);
restart = true;
}
/* Release hold on the relation */
RelationDecrementReferenceCount(relation);
/* Now, restart the hashtable scan if needed */
if (restart)
{
hash_seq_term(&status);
hash_seq_init(&status, RelationIdCache);
}
}
/*
* Lastly, write out new relcache cache files if needed. We don't bother
* to distinguish cases where only one of the two needs an update.
*/
if (needNewCacheFile)
{
/*
* Force all the catcaches to finish initializing and thereby open the
* catalogs and indexes they use. This will preload the relcache with
* entries for all the most important system catalogs and indexes, so
* that the init files will be most useful for future backends.
*/
InitCatalogCachePhase2();
/* now write the files */
write_relcache_init_file(true);
write_relcache_init_file(false);
}
}
/*
* Load one critical system index into the relcache
*
* indexoid is the OID of the target index, heapoid is the OID of the catalog
* it belongs to.
*/
static void
load_critical_index(Oid indexoid, Oid heapoid)
{
Relation ird;
/*
* We must lock the underlying catalog before locking the index to avoid
* deadlock, since RelationBuildDesc might well need to read the catalog,
* and if anyone else is exclusive-locking this catalog and index they'll
* be doing it in that order.
*/
LockRelationOid(heapoid, AccessShareLock);
LockRelationOid(indexoid, AccessShareLock);
ird = RelationBuildDesc(indexoid, true);
if (ird == NULL)
elog(PANIC, "could not open critical system index %u", indexoid);
ird->rd_isnailed = true;
ird->rd_refcnt = 1;
UnlockRelationOid(indexoid, AccessShareLock);
UnlockRelationOid(heapoid, AccessShareLock);
}
/*
* GetPgClassDescriptor -- get a predefined tuple descriptor for pg_class
* GetPgIndexDescriptor -- get a predefined tuple descriptor for pg_index
*
* We need this kluge because we have to be able to access non-fixed-width
* fields of pg_class and pg_index before we have the standard catalog caches
* available. We use predefined data that's set up in just the same way as
* the bootstrapped reldescs used by formrdesc(). The resulting tupdesc is
* not 100% kosher: it does not have the correct rowtype OID in tdtypeid, nor
* does it have a TupleConstr field. But it's good enough for the purpose of
* extracting fields.
*/
static TupleDesc
BuildHardcodedDescriptor(int natts, const FormData_pg_attribute *attrs,
bool hasoids)
{
TupleDesc result;
MemoryContext oldcxt;
int i;
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
result = CreateTemplateTupleDesc(natts, hasoids);
result->tdtypeid = RECORDOID; /* not right, but we don't care */
result->tdtypmod = -1;
for (i = 0; i < natts; i++)
{
memcpy(TupleDescAttr(result, i), &attrs[i], ATTRIBUTE_FIXED_PART_SIZE);
/* make sure attcacheoff is valid */
TupleDescAttr(result, i)->attcacheoff = -1;
}
/* initialize first attribute's attcacheoff, cf RelationBuildTupleDesc */
TupleDescAttr(result, 0)->attcacheoff = 0;
/* Note: we don't bother to set up a TupleConstr entry */
MemoryContextSwitchTo(oldcxt);
return result;
}
static TupleDesc
GetPgClassDescriptor(void)
{
static TupleDesc pgclassdesc = NULL;
/* Already done? */
if (pgclassdesc == NULL)
pgclassdesc = BuildHardcodedDescriptor(Natts_pg_class,
Desc_pg_class,
true);
return pgclassdesc;
}
static TupleDesc
GetPgIndexDescriptor(void)
{
static TupleDesc pgindexdesc = NULL;
/* Already done? */
if (pgindexdesc == NULL)
pgindexdesc = BuildHardcodedDescriptor(Natts_pg_index,
Desc_pg_index,
false);
return pgindexdesc;
}
/*
* Load any default attribute value definitions for the relation.
*/
static void
AttrDefaultFetch(Relation relation)
{
AttrDefault *attrdef = relation->rd_att->constr->defval;
int ndef = relation->rd_att->constr->num_defval;
Relation adrel;
SysScanDesc adscan;
ScanKeyData skey;
HeapTuple htup;
Datum val;
bool isnull;
int found;
int i;
ScanKeyInit(&skey,
Anum_pg_attrdef_adrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
adrel = heap_open(AttrDefaultRelationId, AccessShareLock);
adscan = systable_beginscan(adrel, AttrDefaultIndexId, true,
NULL, 1, &skey);
found = 0;
while (HeapTupleIsValid(htup = systable_getnext(adscan)))
{
Form_pg_attrdef adform = (Form_pg_attrdef) GETSTRUCT(htup);
Form_pg_attribute attr = TupleDescAttr(relation->rd_att, adform->adnum - 1);
for (i = 0; i < ndef; i++)
{
if (adform->adnum != attrdef[i].adnum)
continue;
if (attrdef[i].adbin != NULL)
elog(WARNING, "multiple attrdef records found for attr %s of rel %s",
NameStr(attr->attname),
RelationGetRelationName(relation));
else
found++;
val = fastgetattr(htup,
Anum_pg_attrdef_adbin,
adrel->rd_att, &isnull);
if (isnull)
elog(WARNING, "null adbin for attr %s of rel %s",
NameStr(attr->attname),
RelationGetRelationName(relation));
else
{
/* detoast and convert to cstring in caller's context */
char *s = TextDatumGetCString(val);
attrdef[i].adbin = MemoryContextStrdup(CacheMemoryContext, s);
pfree(s);
}
break;
}
if (i >= ndef)
elog(WARNING, "unexpected attrdef record found for attr %d of rel %s",
adform->adnum, RelationGetRelationName(relation));
}
systable_endscan(adscan);
heap_close(adrel, AccessShareLock);
if (found != ndef)
elog(WARNING, "%d attrdef record(s) missing for rel %s",
ndef - found, RelationGetRelationName(relation));
}
/*
* Load any check constraints for the relation.
*/
static void
CheckConstraintFetch(Relation relation)
{
ConstrCheck *check = relation->rd_att->constr->check;
int ncheck = relation->rd_att->constr->num_check;
Relation conrel;
SysScanDesc conscan;
ScanKeyData skey[1];
HeapTuple htup;
int found = 0;
ScanKeyInit(&skey[0],
Anum_pg_constraint_conrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
conrel = heap_open(ConstraintRelationId, AccessShareLock);
conscan = systable_beginscan(conrel, ConstraintRelidIndexId, true,
NULL, 1, skey);
while (HeapTupleIsValid(htup = systable_getnext(conscan)))
{
Form_pg_constraint conform = (Form_pg_constraint) GETSTRUCT(htup);
Datum val;
bool isnull;
char *s;
/* We want check constraints only */
if (conform->contype != CONSTRAINT_CHECK)
continue;
if (found >= ncheck)
elog(ERROR, "unexpected constraint record found for rel %s",
RelationGetRelationName(relation));
check[found].ccvalid = conform->convalidated;
check[found].ccnoinherit = conform->connoinherit;
check[found].ccname = MemoryContextStrdup(CacheMemoryContext,
NameStr(conform->conname));
/* Grab and test conbin is actually set */
val = fastgetattr(htup,
Anum_pg_constraint_conbin,
conrel->rd_att, &isnull);
if (isnull)
elog(ERROR, "null conbin for rel %s",
RelationGetRelationName(relation));
/* detoast and convert to cstring in caller's context */
s = TextDatumGetCString(val);
check[found].ccbin = MemoryContextStrdup(CacheMemoryContext, s);
pfree(s);
found++;
}
systable_endscan(conscan);
heap_close(conrel, AccessShareLock);
if (found != ncheck)
elog(ERROR, "%d constraint record(s) missing for rel %s",
ncheck - found, RelationGetRelationName(relation));
/* Sort the records so that CHECKs are applied in a deterministic order */
if (ncheck > 1)
qsort(check, ncheck, sizeof(ConstrCheck), CheckConstraintCmp);
}
/*
* qsort comparator to sort ConstrCheck entries by name
*/
static int
CheckConstraintCmp(const void *a, const void *b)
{
const ConstrCheck *ca = (const ConstrCheck *) a;
const ConstrCheck *cb = (const ConstrCheck *) b;
return strcmp(ca->ccname, cb->ccname);
}
/*
* RelationGetFKeyList -- get a list of foreign key info for the relation
*
* Returns a list of ForeignKeyCacheInfo structs, one per FK constraining
* the given relation. This data is a direct copy of relevant fields from
* pg_constraint. The list items are in no particular order.
*
* CAUTION: the returned list is part of the relcache's data, and could
* vanish in a relcache entry reset. Callers must inspect or copy it
* before doing anything that might trigger a cache flush, such as
* system catalog accesses. copyObject() can be used if desired.
* (We define it this way because current callers want to filter and
* modify the list entries anyway, so copying would be a waste of time.)
*/
List *
RelationGetFKeyList(Relation relation)
{
List *result;
Relation conrel;
SysScanDesc conscan;
ScanKeyData skey;
HeapTuple htup;
List *oldlist;
MemoryContext oldcxt;
/* Quick exit if we already computed the list. */
if (relation->rd_fkeyvalid)
return relation->rd_fkeylist;
/* Fast path: if it doesn't have any triggers, it can't have FKs */
if (!relation->rd_rel->relhastriggers)
return NIL;
/*
* We build the list we intend to return (in the caller's context) while
* doing the scan. After successfully completing the scan, we copy that
* list into the relcache entry. This avoids cache-context memory leakage
* if we get some sort of error partway through.
*/
result = NIL;
/* Prepare to scan pg_constraint for entries having conrelid = this rel. */
ScanKeyInit(&skey,
Anum_pg_constraint_conrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
conrel = heap_open(ConstraintRelationId, AccessShareLock);
conscan = systable_beginscan(conrel, ConstraintRelidIndexId, true,
NULL, 1, &skey);
while (HeapTupleIsValid(htup = systable_getnext(conscan)))
{
Form_pg_constraint constraint = (Form_pg_constraint) GETSTRUCT(htup);
ForeignKeyCacheInfo *info;
Datum adatum;
bool isnull;
ArrayType *arr;
int nelem;
/* consider only foreign keys */
if (constraint->contype != CONSTRAINT_FOREIGN)
continue;
info = makeNode(ForeignKeyCacheInfo);
info->conrelid = constraint->conrelid;
info->confrelid = constraint->confrelid;
/* Extract data from conkey field */
adatum = fastgetattr(htup, Anum_pg_constraint_conkey,
conrel->rd_att, &isnull);
if (isnull)
elog(ERROR, "null conkey for rel %s",
RelationGetRelationName(relation));
arr = DatumGetArrayTypeP(adatum); /* ensure not toasted */
nelem = ARR_DIMS(arr)[0];
if (ARR_NDIM(arr) != 1 ||
nelem < 1 ||
nelem > INDEX_MAX_KEYS ||
ARR_HASNULL(arr) ||
ARR_ELEMTYPE(arr) != INT2OID)
elog(ERROR, "conkey is not a 1-D smallint array");
info->nkeys = nelem;
memcpy(info->conkey, ARR_DATA_PTR(arr), nelem * sizeof(AttrNumber));
/* Likewise for confkey */
adatum = fastgetattr(htup, Anum_pg_constraint_confkey,
conrel->rd_att, &isnull);
if (isnull)
elog(ERROR, "null confkey for rel %s",
RelationGetRelationName(relation));
arr = DatumGetArrayTypeP(adatum); /* ensure not toasted */
nelem = ARR_DIMS(arr)[0];
if (ARR_NDIM(arr) != 1 ||
nelem != info->nkeys ||
ARR_HASNULL(arr) ||
ARR_ELEMTYPE(arr) != INT2OID)
elog(ERROR, "confkey is not a 1-D smallint array");
memcpy(info->confkey, ARR_DATA_PTR(arr), nelem * sizeof(AttrNumber));
/* Likewise for conpfeqop */
adatum = fastgetattr(htup, Anum_pg_constraint_conpfeqop,
conrel->rd_att, &isnull);
if (isnull)
elog(ERROR, "null conpfeqop for rel %s",
RelationGetRelationName(relation));
arr = DatumGetArrayTypeP(adatum); /* ensure not toasted */
nelem = ARR_DIMS(arr)[0];
if (ARR_NDIM(arr) != 1 ||
nelem != info->nkeys ||
ARR_HASNULL(arr) ||
ARR_ELEMTYPE(arr) != OIDOID)
elog(ERROR, "conpfeqop is not a 1-D OID array");
memcpy(info->conpfeqop, ARR_DATA_PTR(arr), nelem * sizeof(Oid));
/* Add FK's node to the result list */
result = lappend(result, info);
}
systable_endscan(conscan);
heap_close(conrel, AccessShareLock);
/* Now save a copy of the completed list in the relcache entry. */
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
oldlist = relation->rd_fkeylist;
relation->rd_fkeylist = copyObject(result);
relation->rd_fkeyvalid = true;
MemoryContextSwitchTo(oldcxt);
/* Don't leak the old list, if there is one */
list_free_deep(oldlist);
return result;
}
/*
* RelationGetIndexList -- get a list of OIDs of indexes on this relation
*
* The index list is created only if someone requests it. We scan pg_index
* to find relevant indexes, and add the list to the relcache entry so that
* we won't have to compute it again. Note that shared cache inval of a
* relcache entry will delete the old list and set rd_indexvalid to 0,
* so that we must recompute the index list on next request. This handles
* creation or deletion of an index.
*
* Indexes that are marked not IndexIsLive are omitted from the returned list.
* Such indexes are expected to be dropped momentarily, and should not be
* touched at all by any caller of this function.
*
* The returned list is guaranteed to be sorted in order by OID. This is
* needed by the executor, since for index types that we obtain exclusive
* locks on when updating the index, all backends must lock the indexes in
* the same order or we will get deadlocks (see ExecOpenIndices()). Any
* consistent ordering would do, but ordering by OID is easy.
*
* Since shared cache inval causes the relcache's copy of the list to go away,
* we return a copy of the list palloc'd in the caller's context. The caller
* may list_free() the returned list after scanning it. This is necessary
* since the caller will typically be doing syscache lookups on the relevant
* indexes, and syscache lookup could cause SI messages to be processed!
*
* We also update rd_oidindex, which this module treats as effectively part
* of the index list. rd_oidindex is valid when rd_indexvalid isn't zero;
* it is the pg_class OID of a unique index on OID when the relation has one,
* and InvalidOid if there is no such index.
*
* In exactly the same way, we update rd_pkindex, which is the OID of the
* relation's primary key index if any, else InvalidOid; and rd_replidindex,
* which is the pg_class OID of an index to be used as the relation's
* replication identity index, or InvalidOid if there is no such index.
*/
List *
RelationGetIndexList(Relation relation)
{
Relation indrel;
SysScanDesc indscan;
ScanKeyData skey;
HeapTuple htup;
List *result;
List *oldlist;
char replident = relation->rd_rel->relreplident;
Oid oidIndex = InvalidOid;
Oid pkeyIndex = InvalidOid;
Oid candidateIndex = InvalidOid;
MemoryContext oldcxt;
/* Quick exit if we already computed the list. */
if (relation->rd_indexvalid != 0)
return list_copy(relation->rd_indexlist);
/*
* We build the list we intend to return (in the caller's context) while
* doing the scan. After successfully completing the scan, we copy that
* list into the relcache entry. This avoids cache-context memory leakage
* if we get some sort of error partway through.
*/
result = NIL;
oidIndex = InvalidOid;
/* Prepare to scan pg_index for entries having indrelid = this rel. */
ScanKeyInit(&skey,
Anum_pg_index_indrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
indrel = heap_open(IndexRelationId, AccessShareLock);
indscan = systable_beginscan(indrel, IndexIndrelidIndexId, true,
NULL, 1, &skey);
while (HeapTupleIsValid(htup = systable_getnext(indscan)))
{
Form_pg_index index = (Form_pg_index) GETSTRUCT(htup);
Datum indclassDatum;
oidvector *indclass;
bool isnull;
/*
* Ignore any indexes that are currently being dropped. This will
* prevent them from being searched, inserted into, or considered in
* HOT-safety decisions. It's unsafe to touch such an index at all
* since its catalog entries could disappear at any instant.
*/
if (!IndexIsLive(index))
continue;
/* Add index's OID to result list in the proper order */
result = insert_ordered_oid(result, index->indexrelid);
/*
* indclass cannot be referenced directly through the C struct,
* because it comes after the variable-width indkey field. Must
* extract the datum the hard way...
*/
indclassDatum = heap_getattr(htup,
Anum_pg_index_indclass,
GetPgIndexDescriptor(),
&isnull);
Assert(!isnull);
indclass = (oidvector *) DatumGetPointer(indclassDatum);
/*
* Invalid, non-unique, non-immediate or predicate indexes aren't
* interesting for either oid indexes or replication identity indexes,
* so don't check them.
*/
if (!IndexIsValid(index) || !index->indisunique ||
!index->indimmediate ||
!heap_attisnull(htup, Anum_pg_index_indpred))
continue;
/* Check to see if is a usable btree index on OID */
if (index->indnatts == 1 &&
index->indkey.values[0] == ObjectIdAttributeNumber &&
indclass->values[0] == OID_BTREE_OPS_OID)
oidIndex = index->indexrelid;
/* remember primary key index if any */
if (index->indisprimary)
pkeyIndex = index->indexrelid;
/* remember explicitly chosen replica index */
if (index->indisreplident)
candidateIndex = index->indexrelid;
}
systable_endscan(indscan);
heap_close(indrel, AccessShareLock);
/* Now save a copy of the completed list in the relcache entry. */
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
oldlist = relation->rd_indexlist;
relation->rd_indexlist = list_copy(result);
relation->rd_oidindex = oidIndex;
relation->rd_pkindex = pkeyIndex;
if (replident == REPLICA_IDENTITY_DEFAULT && OidIsValid(pkeyIndex))
relation->rd_replidindex = pkeyIndex;
else if (replident == REPLICA_IDENTITY_INDEX && OidIsValid(candidateIndex))
relation->rd_replidindex = candidateIndex;
else
relation->rd_replidindex = InvalidOid;
relation->rd_indexvalid = 1;
MemoryContextSwitchTo(oldcxt);
/* Don't leak the old list, if there is one */
list_free(oldlist);
return result;
}
/*
* RelationGetStatExtList
* get a list of OIDs of statistics objects on this relation
*
* The statistics list is created only if someone requests it, in a way
* similar to RelationGetIndexList(). We scan pg_statistic_ext to find
* relevant statistics, and add the list to the relcache entry so that we
* won't have to compute it again. Note that shared cache inval of a
* relcache entry will delete the old list and set rd_statvalid to 0,
* so that we must recompute the statistics list on next request. This
* handles creation or deletion of a statistics object.
*
* The returned list is guaranteed to be sorted in order by OID, although
* this is not currently needed.
*
* Since shared cache inval causes the relcache's copy of the list to go away,
* we return a copy of the list palloc'd in the caller's context. The caller
* may list_free() the returned list after scanning it. This is necessary
* since the caller will typically be doing syscache lookups on the relevant
* statistics, and syscache lookup could cause SI messages to be processed!
*/
List *
RelationGetStatExtList(Relation relation)
{
Relation indrel;
SysScanDesc indscan;
ScanKeyData skey;
HeapTuple htup;
List *result;
List *oldlist;
MemoryContext oldcxt;
/* Quick exit if we already computed the list. */
if (relation->rd_statvalid != 0)
return list_copy(relation->rd_statlist);
/*
* We build the list we intend to return (in the caller's context) while
* doing the scan. After successfully completing the scan, we copy that
* list into the relcache entry. This avoids cache-context memory leakage
* if we get some sort of error partway through.
*/
result = NIL;
/*
* Prepare to scan pg_statistic_ext for entries having stxrelid = this
* rel.
*/
ScanKeyInit(&skey,
Anum_pg_statistic_ext_stxrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
indrel = heap_open(StatisticExtRelationId, AccessShareLock);
indscan = systable_beginscan(indrel, StatisticExtRelidIndexId, true,
NULL, 1, &skey);
while (HeapTupleIsValid(htup = systable_getnext(indscan)))
result = insert_ordered_oid(result, HeapTupleGetOid(htup));
systable_endscan(indscan);
heap_close(indrel, AccessShareLock);
/* Now save a copy of the completed list in the relcache entry. */
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
oldlist = relation->rd_statlist;
relation->rd_statlist = list_copy(result);
relation->rd_statvalid = true;
MemoryContextSwitchTo(oldcxt);
/* Don't leak the old list, if there is one */
list_free(oldlist);
return result;
}
/*
* insert_ordered_oid
* Insert a new Oid into a sorted list of Oids, preserving ordering
*
* Building the ordered list this way is O(N^2), but with a pretty small
* constant, so for the number of entries we expect it will probably be
* faster than trying to apply qsort(). Most tables don't have very many
* indexes...
*/
static List *
insert_ordered_oid(List *list, Oid datum)
{
ListCell *prev;
/* Does the datum belong at the front? */
if (list == NIL || datum < linitial_oid(list))
return lcons_oid(datum, list);
/* No, so find the entry it belongs after */
prev = list_head(list);
for (;;)
{
ListCell *curr = lnext(prev);
if (curr == NULL || datum < lfirst_oid(curr))
break; /* it belongs after 'prev', before 'curr' */
prev = curr;
}
/* Insert datum into list after 'prev' */
lappend_cell_oid(list, prev, datum);
return list;
}
/*
* RelationSetIndexList -- externally force the index list contents
*
* This is used to temporarily override what we think the set of valid
* indexes is (including the presence or absence of an OID index).
* The forcing will be valid only until transaction commit or abort.
*
* This should only be applied to nailed relations, because in a non-nailed
* relation the hacked index list could be lost at any time due to SI
* messages. In practice it is only used on pg_class (see REINDEX).
*
* It is up to the caller to make sure the given list is correctly ordered.
*
* We deliberately do not change rd_indexattr here: even when operating
* with a temporary partial index list, HOT-update decisions must be made
* correctly with respect to the full index set. It is up to the caller
* to ensure that a correct rd_indexattr set has been cached before first
* calling RelationSetIndexList; else a subsequent inquiry might cause a
* wrong rd_indexattr set to get computed and cached. Likewise, we do not
* touch rd_keyattr, rd_pkattr or rd_idattr.
*/
void
RelationSetIndexList(Relation relation, List *indexIds, Oid oidIndex)
{
MemoryContext oldcxt;
Assert(relation->rd_isnailed);
/* Copy the list into the cache context (could fail for lack of mem) */
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
indexIds = list_copy(indexIds);
MemoryContextSwitchTo(oldcxt);
/* Okay to replace old list */
list_free(relation->rd_indexlist);
relation->rd_indexlist = indexIds;
relation->rd_oidindex = oidIndex;
/*
* For the moment, assume the target rel hasn't got a pk or replica index.
* We'll load them on demand in the API that wraps access to them.
*/
relation->rd_pkindex = InvalidOid;
relation->rd_replidindex = InvalidOid;
relation->rd_indexvalid = 2; /* mark list as forced */
/* Flag relation as needing eoxact cleanup (to reset the list) */
EOXactListAdd(relation);
}
/*
* RelationGetOidIndex -- get the pg_class OID of the relation's OID index
*
* Returns InvalidOid if there is no such index.
*/
Oid
RelationGetOidIndex(Relation relation)
{
List *ilist;
/*
* If relation doesn't have OIDs at all, caller is probably confused. (We
* could just silently return InvalidOid, but it seems better to throw an
* assertion.)
*/
Assert(relation->rd_rel->relhasoids);
if (relation->rd_indexvalid == 0)
{
/* RelationGetIndexList does the heavy lifting. */
ilist = RelationGetIndexList(relation);
list_free(ilist);
Assert(relation->rd_indexvalid != 0);
}
return relation->rd_oidindex;
}
/*
* RelationGetPrimaryKeyIndex -- get OID of the relation's primary key index
*
* Returns InvalidOid if there is no such index.
*/
Oid
RelationGetPrimaryKeyIndex(Relation relation)
{
List *ilist;
if (relation->rd_indexvalid == 0)
{
/* RelationGetIndexList does the heavy lifting. */
ilist = RelationGetIndexList(relation);
list_free(ilist);
Assert(relation->rd_indexvalid != 0);
}
return relation->rd_pkindex;
}
/*
* RelationGetReplicaIndex -- get OID of the relation's replica identity index
*
* Returns InvalidOid if there is no such index.
*/
Oid
RelationGetReplicaIndex(Relation relation)
{
List *ilist;
if (relation->rd_indexvalid == 0)
{
/* RelationGetIndexList does the heavy lifting. */
ilist = RelationGetIndexList(relation);
list_free(ilist);
Assert(relation->rd_indexvalid != 0);
}
return relation->rd_replidindex;
}
/*
* RelationGetIndexExpressions -- get the index expressions for an index
*
* We cache the result of transforming pg_index.indexprs into a node tree.
* If the rel is not an index or has no expressional columns, we return NIL.
* Otherwise, the returned tree is copied into the caller's memory context.
* (We don't want to return a pointer to the relcache copy, since it could
* disappear due to relcache invalidation.)
*/
List *
RelationGetIndexExpressions(Relation relation)
{
List *result;
Datum exprsDatum;
bool isnull;
char *exprsString;
MemoryContext oldcxt;
/* Quick exit if we already computed the result. */
if (relation->rd_indexprs)
return copyObject(relation->rd_indexprs);
/* Quick exit if there is nothing to do. */
if (relation->rd_indextuple == NULL ||
heap_attisnull(relation->rd_indextuple, Anum_pg_index_indexprs))
return NIL;
/*
* We build the tree we intend to return in the caller's context. After
* successfully completing the work, we copy it into the relcache entry.
* This avoids problems if we get some sort of error partway through.
*/
exprsDatum = heap_getattr(relation->rd_indextuple,
Anum_pg_index_indexprs,
GetPgIndexDescriptor(),
&isnull);
Assert(!isnull);
exprsString = TextDatumGetCString(exprsDatum);
result = (List *) stringToNode(exprsString);
pfree(exprsString);
/*
* Run the expressions through eval_const_expressions. This is not just an
* optimization, but is necessary, because the planner will be comparing
* them to similarly-processed qual clauses, and may fail to detect valid
* matches without this. We don't bother with canonicalize_qual, however.
*/
result = (List *) eval_const_expressions(NULL, (Node *) result);
result = (List *) canonicalize_qual((Expr *) result);
/* May as well fix opfuncids too */
fix_opfuncids((Node *) result);
/* Now save a copy of the completed tree in the relcache entry. */
oldcxt = MemoryContextSwitchTo(relation->rd_indexcxt);
relation->rd_indexprs = copyObject(result);
MemoryContextSwitchTo(oldcxt);
return result;
}
/*
* RelationGetIndexPredicate -- get the index predicate for an index
*
* We cache the result of transforming pg_index.indpred into an implicit-AND
* node tree (suitable for use in planning).
* If the rel is not an index or has no predicate, we return NIL.
* Otherwise, the returned tree is copied into the caller's memory context.
* (We don't want to return a pointer to the relcache copy, since it could
* disappear due to relcache invalidation.)
*/
List *
RelationGetIndexPredicate(Relation relation)
{
List *result;
Datum predDatum;
bool isnull;
char *predString;
MemoryContext oldcxt;
/* Quick exit if we already computed the result. */
if (relation->rd_indpred)
return copyObject(relation->rd_indpred);
/* Quick exit if there is nothing to do. */
if (relation->rd_indextuple == NULL ||
heap_attisnull(relation->rd_indextuple, Anum_pg_index_indpred))
return NIL;
/*
* We build the tree we intend to return in the caller's context. After
* successfully completing the work, we copy it into the relcache entry.
* This avoids problems if we get some sort of error partway through.
*/
predDatum = heap_getattr(relation->rd_indextuple,
Anum_pg_index_indpred,
GetPgIndexDescriptor(),
&isnull);
Assert(!isnull);
predString = TextDatumGetCString(predDatum);
result = (List *) stringToNode(predString);
pfree(predString);
/*
* Run the expression through const-simplification and canonicalization.
* This is not just an optimization, but is necessary, because the planner
* will be comparing it to similarly-processed qual clauses, and may fail
* to detect valid matches without this. This must match the processing
* done to qual clauses in preprocess_expression()! (We can skip the
* stuff involving subqueries, however, since we don't allow any in index
* predicates.)
*/
result = (List *) eval_const_expressions(NULL, (Node *) result);
result = (List *) canonicalize_qual((Expr *) result);
/* Also convert to implicit-AND format */
result = make_ands_implicit((Expr *) result);
/* May as well fix opfuncids too */
fix_opfuncids((Node *) result);
/* Now save a copy of the completed tree in the relcache entry. */
oldcxt = MemoryContextSwitchTo(relation->rd_indexcxt);
relation->rd_indpred = copyObject(result);
MemoryContextSwitchTo(oldcxt);
return result;
}
/*
* RelationGetIndexAttrBitmap -- get a bitmap of index attribute numbers
*
* The result has a bit set for each attribute used anywhere in the index
* definitions of all the indexes on this relation. (This includes not only
* simple index keys, but attributes used in expressions and partial-index
* predicates.)
*
* Depending on attrKind, a bitmap covering the attnums for all index columns,
* for all potential foreign key columns, or for all columns in the configured
* replica identity index is returned.
*
* Attribute numbers are offset by FirstLowInvalidHeapAttributeNumber so that
* we can include system attributes (e.g., OID) in the bitmap representation.
*
* Caller had better hold at least RowExclusiveLock on the target relation
* to ensure it is safe (deadlock-free) for us to take locks on the relation's
* indexes. Note that since the introduction of CREATE INDEX CONCURRENTLY,
* that lock level doesn't guarantee a stable set of indexes, so we have to
* be prepared to retry here in case of a change in the set of indexes.
*
* The returned result is palloc'd in the caller's memory context and should
* be bms_free'd when not needed anymore.
*/
Bitmapset *
RelationGetIndexAttrBitmap(Relation relation, IndexAttrBitmapKind attrKind)
{
Bitmapset *indexattrs; /* indexed columns */
Bitmapset *uindexattrs; /* columns in unique indexes */
Bitmapset *pkindexattrs; /* columns in the primary index */
Bitmapset *idindexattrs; /* columns in the replica identity */
List *indexoidlist;
List *newindexoidlist;
Oid relpkindex;
Oid relreplindex;
ListCell *l;
MemoryContext oldcxt;
/* Quick exit if we already computed the result. */
if (relation->rd_indexattr != NULL)
{
switch (attrKind)
{
case INDEX_ATTR_BITMAP_ALL:
return bms_copy(relation->rd_indexattr);
case INDEX_ATTR_BITMAP_KEY:
return bms_copy(relation->rd_keyattr);
case INDEX_ATTR_BITMAP_PRIMARY_KEY:
return bms_copy(relation->rd_pkattr);
case INDEX_ATTR_BITMAP_IDENTITY_KEY:
return bms_copy(relation->rd_idattr);
default:
elog(ERROR, "unknown attrKind %u", attrKind);
}
}
/* Fast path if definitely no indexes */
if (!RelationGetForm(relation)->relhasindex)
return NULL;
/*
* Get cached list of index OIDs. If we have to start over, we do so here.
*/
restart:
indexoidlist = RelationGetIndexList(relation);
/* Fall out if no indexes (but relhasindex was set) */
if (indexoidlist == NIL)
return NULL;
/*
* Copy the rd_pkindex and rd_replidindex values computed by
* RelationGetIndexList before proceeding. This is needed because a
* relcache flush could occur inside index_open below, resetting the
* fields managed by RelationGetIndexList. We need to do the work with
* stable values of these fields.
*/
relpkindex = relation->rd_pkindex;
relreplindex = relation->rd_replidindex;
/*
* For each index, add referenced attributes to indexattrs.
*
* Note: we consider all indexes returned by RelationGetIndexList, even if
* they are not indisready or indisvalid. This is important because an
* index for which CREATE INDEX CONCURRENTLY has just started must be
* included in HOT-safety decisions (see README.HOT). If a DROP INDEX
* CONCURRENTLY is far enough along that we should ignore the index, it
* won't be returned at all by RelationGetIndexList.
*/
indexattrs = NULL;
uindexattrs = NULL;
pkindexattrs = NULL;
idindexattrs = NULL;
foreach(l, indexoidlist)
{
Oid indexOid = lfirst_oid(l);
Relation indexDesc;
IndexInfo *indexInfo;
int i;
bool isKey; /* candidate key */
bool isPK; /* primary key */
bool isIDKey; /* replica identity index */
indexDesc = index_open(indexOid, AccessShareLock);
/* Extract index key information from the index's pg_index row */
indexInfo = BuildIndexInfo(indexDesc);
/* Can this index be referenced by a foreign key? */
isKey = indexInfo->ii_Unique &&
indexInfo->ii_Expressions == NIL &&
indexInfo->ii_Predicate == NIL;
/* Is this a primary key? */
isPK = (indexOid == relpkindex);
/* Is this index the configured (or default) replica identity? */
isIDKey = (indexOid == relreplindex);
/* Collect simple attribute references */
for (i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
{
int attrnum = indexInfo->ii_KeyAttrNumbers[i];
if (attrnum != 0)
{
indexattrs = bms_add_member(indexattrs,
attrnum - FirstLowInvalidHeapAttributeNumber);
if (isKey)
uindexattrs = bms_add_member(uindexattrs,
attrnum - FirstLowInvalidHeapAttributeNumber);
if (isPK)
pkindexattrs = bms_add_member(pkindexattrs,
attrnum - FirstLowInvalidHeapAttributeNumber);
if (isIDKey)
idindexattrs = bms_add_member(idindexattrs,
attrnum - FirstLowInvalidHeapAttributeNumber);
}
}
/* Collect all attributes used in expressions, too */
pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
/* Collect all attributes in the index predicate, too */
pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
index_close(indexDesc, AccessShareLock);
}
/*
* During one of the index_opens in the above loop, we might have received
* a relcache flush event on this relcache entry, which might have been
* signaling a change in the rel's index list. If so, we'd better start
* over to ensure we deliver up-to-date attribute bitmaps.
*/
newindexoidlist = RelationGetIndexList(relation);
if (equal(indexoidlist, newindexoidlist) &&
relpkindex == relation->rd_pkindex &&
relreplindex == relation->rd_replidindex)
{
/* Still the same index set, so proceed */
list_free(newindexoidlist);
list_free(indexoidlist);
}
else
{
/* Gotta do it over ... might as well not leak memory */
list_free(newindexoidlist);
list_free(indexoidlist);
bms_free(uindexattrs);
bms_free(pkindexattrs);
bms_free(idindexattrs);
bms_free(indexattrs);
goto restart;
}
/* Don't leak the old values of these bitmaps, if any */
bms_free(relation->rd_indexattr);
relation->rd_indexattr = NULL;
bms_free(relation->rd_keyattr);
relation->rd_keyattr = NULL;
bms_free(relation->rd_pkattr);
relation->rd_pkattr = NULL;
bms_free(relation->rd_idattr);
relation->rd_idattr = NULL;
/*
* Now save copies of the bitmaps in the relcache entry. We intentionally
* set rd_indexattr last, because that's the one that signals validity of
* the values; if we run out of memory before making that copy, we won't
* leave the relcache entry looking like the other ones are valid but
* empty.
*/
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
relation->rd_keyattr = bms_copy(uindexattrs);
relation->rd_pkattr = bms_copy(pkindexattrs);
relation->rd_idattr = bms_copy(idindexattrs);
relation->rd_indexattr = bms_copy(indexattrs);
MemoryContextSwitchTo(oldcxt);
/* We return our original working copy for caller to play with */
switch (attrKind)
{
case INDEX_ATTR_BITMAP_ALL:
return indexattrs;
case INDEX_ATTR_BITMAP_KEY:
return uindexattrs;
case INDEX_ATTR_BITMAP_PRIMARY_KEY:
return bms_copy(relation->rd_pkattr);
case INDEX_ATTR_BITMAP_IDENTITY_KEY:
return idindexattrs;
default:
elog(ERROR, "unknown attrKind %u", attrKind);
return NULL;
}
}
/*
* RelationGetExclusionInfo -- get info about index's exclusion constraint
*
* This should be called only for an index that is known to have an
* associated exclusion constraint. It returns arrays (palloc'd in caller's
* context) of the exclusion operator OIDs, their underlying functions'
* OIDs, and their strategy numbers in the index's opclasses. We cache
* all this information since it requires a fair amount of work to get.
*/
void
RelationGetExclusionInfo(Relation indexRelation,
Oid **operators,
Oid **procs,
uint16 **strategies)
{
int ncols = indexRelation->rd_rel->relnatts;
Oid *ops;
Oid *funcs;
uint16 *strats;
Relation conrel;
SysScanDesc conscan;
ScanKeyData skey[1];
HeapTuple htup;
bool found;
MemoryContext oldcxt;
int i;
/* Allocate result space in caller context */
*operators = ops = (Oid *) palloc(sizeof(Oid) * ncols);
*procs = funcs = (Oid *) palloc(sizeof(Oid) * ncols);
*strategies = strats = (uint16 *) palloc(sizeof(uint16) * ncols);
/* Quick exit if we have the data cached already */
if (indexRelation->rd_exclstrats != NULL)
{
memcpy(ops, indexRelation->rd_exclops, sizeof(Oid) * ncols);
memcpy(funcs, indexRelation->rd_exclprocs, sizeof(Oid) * ncols);
memcpy(strats, indexRelation->rd_exclstrats, sizeof(uint16) * ncols);
return;
}
/*
* Search pg_constraint for the constraint associated with the index. To
* make this not too painfully slow, we use the index on conrelid; that
* will hold the parent relation's OID not the index's own OID.
*/
ScanKeyInit(&skey[0],
Anum_pg_constraint_conrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(indexRelation->rd_index->indrelid));
conrel = heap_open(ConstraintRelationId, AccessShareLock);
conscan = systable_beginscan(conrel, ConstraintRelidIndexId, true,
NULL, 1, skey);
found = false;
while (HeapTupleIsValid(htup = systable_getnext(conscan)))
{
Form_pg_constraint conform = (Form_pg_constraint) GETSTRUCT(htup);
Datum val;
bool isnull;
ArrayType *arr;
int nelem;
/* We want the exclusion constraint owning the index */
if (conform->contype != CONSTRAINT_EXCLUSION ||
conform->conindid != RelationGetRelid(indexRelation))
continue;
/* There should be only one */
if (found)
elog(ERROR, "unexpected exclusion constraint record found for rel %s",
RelationGetRelationName(indexRelation));
found = true;
/* Extract the operator OIDS from conexclop */
val = fastgetattr(htup,
Anum_pg_constraint_conexclop,
conrel->rd_att, &isnull);
if (isnull)
elog(ERROR, "null conexclop for rel %s",
RelationGetRelationName(indexRelation));
arr = DatumGetArrayTypeP(val); /* ensure not toasted */
nelem = ARR_DIMS(arr)[0];
if (ARR_NDIM(arr) != 1 ||
nelem != ncols ||
ARR_HASNULL(arr) ||
ARR_ELEMTYPE(arr) != OIDOID)
elog(ERROR, "conexclop is not a 1-D Oid array");
memcpy(ops, ARR_DATA_PTR(arr), sizeof(Oid) * ncols);
}
systable_endscan(conscan);
heap_close(conrel, AccessShareLock);
if (!found)
elog(ERROR, "exclusion constraint record missing for rel %s",
RelationGetRelationName(indexRelation));
/* We need the func OIDs and strategy numbers too */
for (i = 0; i < ncols; i++)
{
funcs[i] = get_opcode(ops[i]);
strats[i] = get_op_opfamily_strategy(ops[i],
indexRelation->rd_opfamily[i]);
/* shouldn't fail, since it was checked at index creation */
if (strats[i] == InvalidStrategy)
elog(ERROR, "could not find strategy for operator %u in family %u",
ops[i], indexRelation->rd_opfamily[i]);
}
/* Save a copy of the results in the relcache entry. */
oldcxt = MemoryContextSwitchTo(indexRelation->rd_indexcxt);
indexRelation->rd_exclops = (Oid *) palloc(sizeof(Oid) * ncols);
indexRelation->rd_exclprocs = (Oid *) palloc(sizeof(Oid) * ncols);
indexRelation->rd_exclstrats = (uint16 *) palloc(sizeof(uint16) * ncols);
memcpy(indexRelation->rd_exclops, ops, sizeof(Oid) * ncols);
memcpy(indexRelation->rd_exclprocs, funcs, sizeof(Oid) * ncols);
memcpy(indexRelation->rd_exclstrats, strats, sizeof(uint16) * ncols);
MemoryContextSwitchTo(oldcxt);
}
/*
* Get publication actions for the given relation.
*/
struct PublicationActions *
GetRelationPublicationActions(Relation relation)
{
List *puboids;
ListCell *lc;
MemoryContext oldcxt;
PublicationActions *pubactions = palloc0(sizeof(PublicationActions));
if (relation->rd_pubactions)
return memcpy(pubactions, relation->rd_pubactions,
sizeof(PublicationActions));
/* Fetch the publication membership info. */
puboids = GetRelationPublications(RelationGetRelid(relation));
puboids = list_concat_unique_oid(puboids, GetAllTablesPublications());
foreach(lc, puboids)
{
Oid pubid = lfirst_oid(lc);
HeapTuple tup;
Form_pg_publication pubform;
tup = SearchSysCache1(PUBLICATIONOID, ObjectIdGetDatum(pubid));
if (!HeapTupleIsValid(tup))
elog(ERROR, "cache lookup failed for publication %u", pubid);
pubform = (Form_pg_publication) GETSTRUCT(tup);
pubactions->pubinsert |= pubform->pubinsert;
pubactions->pubupdate |= pubform->pubupdate;
pubactions->pubdelete |= pubform->pubdelete;
ReleaseSysCache(tup);
/*
* If we know everything is replicated, there is no point to check for
* other publications.
*/
if (pubactions->pubinsert && pubactions->pubupdate &&
pubactions->pubdelete)
break;
}
if (relation->rd_pubactions)
{
pfree(relation->rd_pubactions);
relation->rd_pubactions = NULL;
}
/* Now save copy of the actions in the relcache entry. */
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
relation->rd_pubactions = palloc(sizeof(PublicationActions));
memcpy(relation->rd_pubactions, pubactions, sizeof(PublicationActions));
MemoryContextSwitchTo(oldcxt);
return pubactions;
}
/*
* Routines to support ereport() reports of relation-related errors
*
* These could have been put into elog.c, but it seems like a module layering
* violation to have elog.c calling relcache or syscache stuff --- and we
* definitely don't want elog.h including rel.h. So we put them here.
*/
/*
* errtable --- stores schema_name and table_name of a table
* within the current errordata.
*/
int
errtable(Relation rel)
{
err_generic_string(PG_DIAG_SCHEMA_NAME,
get_namespace_name(RelationGetNamespace(rel)));
err_generic_string(PG_DIAG_TABLE_NAME, RelationGetRelationName(rel));
return 0; /* return value does not matter */
}
/*
* errtablecol --- stores schema_name, table_name and column_name
* of a table column within the current errordata.
*
* The column is specified by attribute number --- for most callers, this is
* easier and less error-prone than getting the column name for themselves.
*/
int
errtablecol(Relation rel, int attnum)
{
TupleDesc reldesc = RelationGetDescr(rel);
const char *colname;
/* Use reldesc if it's a user attribute, else consult the catalogs */
if (attnum > 0 && attnum <= reldesc->natts)
colname = NameStr(TupleDescAttr(reldesc, attnum - 1)->attname);
else
colname = get_relid_attribute_name(RelationGetRelid(rel), attnum);
return errtablecolname(rel, colname);
}
/*
* errtablecolname --- stores schema_name, table_name and column_name
* of a table column within the current errordata, where the column name is
* given directly rather than extracted from the relation's catalog data.
*
* Don't use this directly unless errtablecol() is inconvenient for some
* reason. This might possibly be needed during intermediate states in ALTER
* TABLE, for instance.
*/
int
errtablecolname(Relation rel, const char *colname)
{
errtable(rel);
err_generic_string(PG_DIAG_COLUMN_NAME, colname);
return 0; /* return value does not matter */
}
/*
* errtableconstraint --- stores schema_name, table_name and constraint_name
* of a table-related constraint within the current errordata.
*/
int
errtableconstraint(Relation rel, const char *conname)
{
errtable(rel);
err_generic_string(PG_DIAG_CONSTRAINT_NAME, conname);
return 0; /* return value does not matter */
}
/*
* load_relcache_init_file, write_relcache_init_file
*
* In late 1992, we started regularly having databases with more than
* a thousand classes in them. With this number of classes, it became
* critical to do indexed lookups on the system catalogs.
*
* Bootstrapping these lookups is very hard. We want to be able to
* use an index on pg_attribute, for example, but in order to do so,
* we must have read pg_attribute for the attributes in the index,
* which implies that we need to use the index.
*
* In order to get around the problem, we do the following:
*
* + When the database system is initialized (at initdb time), we
* don't use indexes. We do sequential scans.
*
* + When the backend is started up in normal mode, we load an image
* of the appropriate relation descriptors, in internal format,
* from an initialization file in the data/base/... directory.
*
* + If the initialization file isn't there, then we create the
* relation descriptors using sequential scans and write 'em to
* the initialization file for use by subsequent backends.
*
* As of Postgres 9.0, there is one local initialization file in each
* database, plus one shared initialization file for shared catalogs.
*
* We could dispense with the initialization files and just build the
* critical reldescs the hard way on every backend startup, but that
* slows down backend startup noticeably.
*
* We can in fact go further, and save more relcache entries than
* just the ones that are absolutely critical; this allows us to speed
* up backend startup by not having to build such entries the hard way.
* Presently, all the catalog and index entries that are referred to
* by catcaches are stored in the initialization files.
*
* The same mechanism that detects when catcache and relcache entries
* need to be invalidated (due to catalog updates) also arranges to
* unlink the initialization files when the contents may be out of date.
* The files will then be rebuilt during the next backend startup.
*/
/*
* load_relcache_init_file -- attempt to load cache from the shared
* or local cache init file
*
* If successful, return true and set criticalRelcachesBuilt or
* criticalSharedRelcachesBuilt to true.
* If not successful, return false.
*
* NOTE: we assume we are already switched into CacheMemoryContext.
*/
static bool
load_relcache_init_file(bool shared)
{
FILE *fp;
char initfilename[MAXPGPATH];
Relation *rels;
int relno,
num_rels,
max_rels,
nailed_rels,
nailed_indexes,
magic;
int i;
if (shared)
snprintf(initfilename, sizeof(initfilename), "global/%s",
RELCACHE_INIT_FILENAME);
else
snprintf(initfilename, sizeof(initfilename), "%s/%s",
DatabasePath, RELCACHE_INIT_FILENAME);
fp = AllocateFile(initfilename, PG_BINARY_R);
if (fp == NULL)
return false;
/*
* Read the index relcache entries from the file. Note we will not enter
* any of them into the cache if the read fails partway through; this
* helps to guard against broken init files.
*/
max_rels = 100;
rels = (Relation *) palloc(max_rels * sizeof(Relation));
num_rels = 0;
nailed_rels = nailed_indexes = 0;
/* check for correct magic number (compatible version) */
if (fread(&magic, 1, sizeof(magic), fp) != sizeof(magic))
goto read_failed;
if (magic != RELCACHE_INIT_FILEMAGIC)
goto read_failed;
for (relno = 0;; relno++)
{
Size len;
size_t nread;
Relation rel;
Form_pg_class relform;
bool has_not_null;
/* first read the relation descriptor length */
nread = fread(&len, 1, sizeof(len), fp);
if (nread != sizeof(len))
{
if (nread == 0)
break; /* end of file */
goto read_failed;
}
/* safety check for incompatible relcache layout */
if (len != sizeof(RelationData))
goto read_failed;
/* allocate another relcache header */
if (num_rels >= max_rels)
{
max_rels *= 2;
rels = (Relation *) repalloc(rels, max_rels * sizeof(Relation));
}
rel = rels[num_rels++] = (Relation) palloc(len);
/* then, read the Relation structure */
if (fread(rel, 1, len, fp) != len)
goto read_failed;
/* next read the relation tuple form */
if (fread(&len, 1, sizeof(len), fp) != sizeof(len))
goto read_failed;
relform = (Form_pg_class) palloc(len);
if (fread(relform, 1, len, fp) != len)
goto read_failed;
rel->rd_rel = relform;
/* initialize attribute tuple forms */
rel->rd_att = CreateTemplateTupleDesc(relform->relnatts,
relform->relhasoids);
rel->rd_att->tdrefcount = 1; /* mark as refcounted */
rel->rd_att->tdtypeid = relform->reltype;
rel->rd_att->tdtypmod = -1; /* unnecessary, but... */
/* next read all the attribute tuple form data entries */
has_not_null = false;
for (i = 0; i < relform->relnatts; i++)
{
Form_pg_attribute attr = TupleDescAttr(rel->rd_att, i);
if (fread(&len, 1, sizeof(len), fp) != sizeof(len))
goto read_failed;
if (len != ATTRIBUTE_FIXED_PART_SIZE)
goto read_failed;
if (fread(attr, 1, len, fp) != len)
goto read_failed;
has_not_null |= attr->attnotnull;
}
/* next read the access method specific field */
if (fread(&len, 1, sizeof(len), fp) != sizeof(len))
goto read_failed;
if (len > 0)
{
rel->rd_options = palloc(len);
if (fread(rel->rd_options, 1, len, fp) != len)
goto read_failed;
if (len != VARSIZE(rel->rd_options))
goto read_failed; /* sanity check */
}
else
{
rel->rd_options = NULL;
}
/* mark not-null status */
if (has_not_null)
{
TupleConstr *constr = (TupleConstr *) palloc0(sizeof(TupleConstr));
constr->has_not_null = true;
rel->rd_att->constr = constr;
}
/* If it's an index, there's more to do */
if (rel->rd_rel->relkind == RELKIND_INDEX)
{
MemoryContext indexcxt;
Oid *opfamily;
Oid *opcintype;
RegProcedure *support;
int nsupport;
int16 *indoption;
Oid *indcollation;
/* Count nailed indexes to ensure we have 'em all */
if (rel->rd_isnailed)
nailed_indexes++;
/* next, read the pg_index tuple */
if (fread(&len, 1, sizeof(len), fp) != sizeof(len))
goto read_failed;
rel->rd_indextuple = (HeapTuple) palloc(len);
if (fread(rel->rd_indextuple, 1, len, fp) != len)
goto read_failed;
/* Fix up internal pointers in the tuple -- see heap_copytuple */
rel->rd_indextuple->t_data = (HeapTupleHeader) ((char *) rel->rd_indextuple + HEAPTUPLESIZE);
rel->rd_index = (Form_pg_index) GETSTRUCT(rel->rd_indextuple);
/*
* prepare index info context --- parameters should match
* RelationInitIndexAccessInfo
*/
indexcxt =
AllocSetContextCreateExtended(CacheMemoryContext,
RelationGetRelationName(rel),
MEMCONTEXT_COPY_NAME,
ALLOCSET_SMALL_SIZES);
rel->rd_indexcxt = indexcxt;
/*
* Now we can fetch the index AM's API struct. (We can't store
* that in the init file, since it contains function pointers that
* might vary across server executions. Fortunately, it should be
* safe to call the amhandler even while bootstrapping indexes.)
*/
InitIndexAmRoutine(rel);
/* next, read the vector of opfamily OIDs */
if (fread(&len, 1, sizeof(len), fp) != sizeof(len))
goto read_failed;
opfamily = (Oid *) MemoryContextAlloc(indexcxt, len);
if (fread(opfamily, 1, len, fp) != len)
goto read_failed;
rel->rd_opfamily = opfamily;
/* next, read the vector of opcintype OIDs */
if (fread(&len, 1, sizeof(len), fp) != sizeof(len))
goto read_failed;
opcintype = (Oid *) MemoryContextAlloc(indexcxt, len);
if (fread(opcintype, 1, len, fp) != len)
goto read_failed;
rel->rd_opcintype = opcintype;
/* next, read the vector of support procedure OIDs */
if (fread(&len, 1, sizeof(len), fp) != sizeof(len))
goto read_failed;
support = (RegProcedure *) MemoryContextAlloc(indexcxt, len);
if (fread(support, 1, len, fp) != len)
goto read_failed;
rel->rd_support = support;
/* next, read the vector of collation OIDs */
if (fread(&len, 1, sizeof(len), fp) != sizeof(len))
goto read_failed;
indcollation = (Oid *) MemoryContextAlloc(indexcxt, len);
if (fread(indcollation, 1, len, fp) != len)
goto read_failed;
rel->rd_indcollation = indcollation;
/* finally, read the vector of indoption values */
if (fread(&len, 1, sizeof(len), fp) != sizeof(len))
goto read_failed;
indoption = (int16 *) MemoryContextAlloc(indexcxt, len);
if (fread(indoption, 1, len, fp) != len)
goto read_failed;
rel->rd_indoption = indoption;
/* set up zeroed fmgr-info vector */
nsupport = relform->relnatts * rel->rd_amroutine->amsupport;
rel->rd_supportinfo = (FmgrInfo *)
MemoryContextAllocZero(indexcxt, nsupport * sizeof(FmgrInfo));
}
else
{
/* Count nailed rels to ensure we have 'em all */
if (rel->rd_isnailed)
nailed_rels++;
Assert(rel->rd_index == NULL);
Assert(rel->rd_indextuple == NULL);
Assert(rel->rd_indexcxt == NULL);
Assert(rel->rd_amroutine == NULL);
Assert(rel->rd_opfamily == NULL);
Assert(rel->rd_opcintype == NULL);
Assert(rel->rd_support == NULL);
Assert(rel->rd_supportinfo == NULL);
Assert(rel->rd_indoption == NULL);
Assert(rel->rd_indcollation == NULL);
}
/*
* Rules and triggers are not saved (mainly because the internal
* format is complex and subject to change). They must be rebuilt if
* needed by RelationCacheInitializePhase3. This is not expected to
* be a big performance hit since few system catalogs have such. Ditto
* for RLS policy data, index expressions, predicates, exclusion info,
* and FDW info.
*/
rel->rd_rules = NULL;
rel->rd_rulescxt = NULL;
rel->trigdesc = NULL;
rel->rd_rsdesc = NULL;
rel->rd_partkeycxt = NULL;
rel->rd_partkey = NULL;
rel->rd_pdcxt = NULL;
rel->rd_partdesc = NULL;
rel->rd_partcheck = NIL;
rel->rd_indexprs = NIL;
rel->rd_indpred = NIL;
rel->rd_exclops = NULL;
rel->rd_exclprocs = NULL;
rel->rd_exclstrats = NULL;
rel->rd_fdwroutine = NULL;
/*
* Reset transient-state fields in the relcache entry
*/
rel->rd_smgr = NULL;
if (rel->rd_isnailed)
rel->rd_refcnt = 1;
else
rel->rd_refcnt = 0;
rel->rd_indexvalid = 0;
rel->rd_fkeylist = NIL;
rel->rd_fkeyvalid = false;
rel->rd_indexlist = NIL;
rel->rd_oidindex = InvalidOid;
rel->rd_pkindex = InvalidOid;
rel->rd_replidindex = InvalidOid;
rel->rd_indexattr = NULL;
rel->rd_keyattr = NULL;
rel->rd_pkattr = NULL;
rel->rd_idattr = NULL;
rel->rd_pubactions = NULL;
rel->rd_statvalid = false;
rel->rd_statlist = NIL;
rel->rd_createSubid = InvalidSubTransactionId;
rel->rd_newRelfilenodeSubid = InvalidSubTransactionId;
rel->rd_amcache = NULL;
MemSet(&rel->pgstat_info, 0, sizeof(rel->pgstat_info));
/*
* Recompute lock and physical addressing info. This is needed in
* case the pg_internal.init file was copied from some other database
* by CREATE DATABASE.
*/
RelationInitLockInfo(rel);
RelationInitPhysicalAddr(rel);
}
/*
* We reached the end of the init file without apparent problem. Did we
* get the right number of nailed items? This is a useful crosscheck in
* case the set of critical rels or indexes changes. However, that should
* not happen in a normally-running system, so let's bleat if it does.
*
* For the shared init file, we're called before client authentication is
* done, which means that elog(WARNING) will go only to the postmaster
* log, where it's easily missed. To ensure that developers notice bad
* values of NUM_CRITICAL_SHARED_RELS/NUM_CRITICAL_SHARED_INDEXES, we put
* an Assert(false) there.
*/
if (shared)
{
if (nailed_rels != NUM_CRITICAL_SHARED_RELS ||
nailed_indexes != NUM_CRITICAL_SHARED_INDEXES)
{
elog(WARNING, "found %d nailed shared rels and %d nailed shared indexes in init file, but expected %d and %d respectively",
nailed_rels, nailed_indexes,
NUM_CRITICAL_SHARED_RELS, NUM_CRITICAL_SHARED_INDEXES);
/* Make sure we get developers' attention about this */
Assert(false);
/* In production builds, recover by bootstrapping the relcache */
goto read_failed;
}
}
else
{
if (nailed_rels != NUM_CRITICAL_LOCAL_RELS ||
nailed_indexes != NUM_CRITICAL_LOCAL_INDEXES)
{
elog(WARNING, "found %d nailed rels and %d nailed indexes in init file, but expected %d and %d respectively",
nailed_rels, nailed_indexes,
NUM_CRITICAL_LOCAL_RELS, NUM_CRITICAL_LOCAL_INDEXES);
/* We don't need an Assert() in this case */
goto read_failed;
}
}
/*
* OK, all appears well.
*
* Now insert all the new relcache entries into the cache.
*/
for (relno = 0; relno < num_rels; relno++)
{
RelationCacheInsert(rels[relno], false);
}
pfree(rels);
FreeFile(fp);
if (shared)
criticalSharedRelcachesBuilt = true;
else
criticalRelcachesBuilt = true;
return true;
/*
* init file is broken, so do it the hard way. We don't bother trying to
* free the clutter we just allocated; it's not in the relcache so it
* won't hurt.
*/
read_failed:
pfree(rels);
FreeFile(fp);
return false;
}
/*
* Write out a new initialization file with the current contents
* of the relcache (either shared rels or local rels, as indicated).
*/
static void
write_relcache_init_file(bool shared)
{
FILE *fp;
char tempfilename[MAXPGPATH];
char finalfilename[MAXPGPATH];
int magic;
HASH_SEQ_STATUS status;
RelIdCacheEnt *idhentry;
int i;
/*
* If we have already received any relcache inval events, there's no
* chance of succeeding so we may as well skip the whole thing.
*/
if (relcacheInvalsReceived != 0L)
return;
/*
* We must write a temporary file and rename it into place. Otherwise,
* another backend starting at about the same time might crash trying to
* read the partially-complete file.
*/
if (shared)
{
snprintf(tempfilename, sizeof(tempfilename), "global/%s.%d",
RELCACHE_INIT_FILENAME, MyProcPid);
snprintf(finalfilename, sizeof(finalfilename), "global/%s",
RELCACHE_INIT_FILENAME);
}
else
{
snprintf(tempfilename, sizeof(tempfilename), "%s/%s.%d",
DatabasePath, RELCACHE_INIT_FILENAME, MyProcPid);
snprintf(finalfilename, sizeof(finalfilename), "%s/%s",
DatabasePath, RELCACHE_INIT_FILENAME);
}
unlink(tempfilename); /* in case it exists w/wrong permissions */
fp = AllocateFile(tempfilename, PG_BINARY_W);
if (fp == NULL)
{
/*
* We used to consider this a fatal error, but we might as well
* continue with backend startup ...
*/
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not create relation-cache initialization file \"%s\": %m",
tempfilename),
errdetail("Continuing anyway, but there's something wrong.")));
return;
}
/*
* Write a magic number to serve as a file version identifier. We can
* change the magic number whenever the relcache layout changes.
*/
magic = RELCACHE_INIT_FILEMAGIC;
if (fwrite(&magic, 1, sizeof(magic), fp) != sizeof(magic))
elog(FATAL, "could not write init file");
/*
* Write all the appropriate reldescs (in no particular order).
*/
hash_seq_init(&status, RelationIdCache);
while ((idhentry = (RelIdCacheEnt *) hash_seq_search(&status)) != NULL)
{
Relation rel = idhentry->reldesc;
Form_pg_class relform = rel->rd_rel;
/* ignore if not correct group */
if (relform->relisshared != shared)
continue;
/*
* Ignore if not supposed to be in init file. We can allow any shared
* relation that's been loaded so far to be in the shared init file,
* but unshared relations must be ones that should be in the local
* file per RelationIdIsInInitFile. (Note: if you want to change the
* criterion for rels to be kept in the init file, see also inval.c.
* The reason for filtering here is to be sure that we don't put
* anything into the local init file for which a relcache inval would
* not cause invalidation of that init file.)
*/
if (!shared && !RelationIdIsInInitFile(RelationGetRelid(rel)))
{
/* Nailed rels had better get stored. */
Assert(!rel->rd_isnailed);
continue;
}
/* first write the relcache entry proper */
write_item(rel, sizeof(RelationData), fp);
/* next write the relation tuple form */
write_item(relform, CLASS_TUPLE_SIZE, fp);
/* next, do all the attribute tuple form data entries */
for (i = 0; i < relform->relnatts; i++)
{
write_item(TupleDescAttr(rel->rd_att, i),
ATTRIBUTE_FIXED_PART_SIZE, fp);
}
/* next, do the access method specific field */
write_item(rel->rd_options,
(rel->rd_options ? VARSIZE(rel->rd_options) : 0),
fp);
/* If it's an index, there's more to do */
if (rel->rd_rel->relkind == RELKIND_INDEX)
{
/* write the pg_index tuple */
/* we assume this was created by heap_copytuple! */
write_item(rel->rd_indextuple,
HEAPTUPLESIZE + rel->rd_indextuple->t_len,
fp);
/* next, write the vector of opfamily OIDs */
write_item(rel->rd_opfamily,
relform->relnatts * sizeof(Oid),
fp);
/* next, write the vector of opcintype OIDs */
write_item(rel->rd_opcintype,
relform->relnatts * sizeof(Oid),
fp);
/* next, write the vector of support procedure OIDs */
write_item(rel->rd_support,
relform->relnatts * (rel->rd_amroutine->amsupport * sizeof(RegProcedure)),
fp);
/* next, write the vector of collation OIDs */
write_item(rel->rd_indcollation,
relform->relnatts * sizeof(Oid),
fp);
/* finally, write the vector of indoption values */
write_item(rel->rd_indoption,
relform->relnatts * sizeof(int16),
fp);
}
}
if (FreeFile(fp))
elog(FATAL, "could not write init file");
/*
* Now we have to check whether the data we've so painstakingly
* accumulated is already obsolete due to someone else's just-committed
* catalog changes. If so, we just delete the temp file and leave it to
* the next backend to try again. (Our own relcache entries will be
* updated by SI message processing, but we can't be sure whether what we
* wrote out was up-to-date.)
*
* This mustn't run concurrently with the code that unlinks an init file
* and sends SI messages, so grab a serialization lock for the duration.
*/
LWLockAcquire(RelCacheInitLock, LW_EXCLUSIVE);
/* Make sure we have seen all incoming SI messages */
AcceptInvalidationMessages();
/*
* If we have received any SI relcache invals since backend start, assume
* we may have written out-of-date data.
*/
if (relcacheInvalsReceived == 0L)
{
/*
* OK, rename the temp file to its final name, deleting any
* previously-existing init file.
*
* Note: a failure here is possible under Cygwin, if some other
* backend is holding open an unlinked-but-not-yet-gone init file. So
* treat this as a noncritical failure; just remove the useless temp
* file on failure.
*/
if (rename(tempfilename, finalfilename) < 0)
unlink(tempfilename);
}
else
{
/* Delete the already-obsolete temp file */
unlink(tempfilename);
}
LWLockRelease(RelCacheInitLock);
}
/* write a chunk of data preceded by its length */
static void
write_item(const void *data, Size len, FILE *fp)
{
if (fwrite(&len, 1, sizeof(len), fp) != sizeof(len))
elog(FATAL, "could not write init file");
if (fwrite(data, 1, len, fp) != len)
elog(FATAL, "could not write init file");
}
/*
* Determine whether a given relation (identified by OID) is one of the ones
* we should store in the local relcache init file.
*
* We must cache all nailed rels, and for efficiency we should cache every rel
* that supports a syscache. The former set is almost but not quite a subset
* of the latter. Currently, we must special-case TriggerRelidNameIndexId,
* which RelationCacheInitializePhase3 chooses to nail for efficiency reasons,
* but which does not support any syscache.
*
* Note: this function is currently never called for shared rels. If it were,
* we'd probably also need a special case for DatabaseNameIndexId, which is
* critical but does not support a syscache.
*/
bool
RelationIdIsInInitFile(Oid relationId)
{
if (relationId == TriggerRelidNameIndexId)
{
/* If this Assert fails, we don't need this special case anymore. */
Assert(!RelationSupportsSysCache(relationId));
return true;
}
return RelationSupportsSysCache(relationId);
}
/*
* Tells whether any index for the relation is unlogged.
*
* Note: There doesn't seem to be any way to have an unlogged index attached
* to a permanent table, but it seems best to keep this general so that it
* returns sensible results even when they seem obvious (like for an unlogged
* table) and to handle possible future unlogged indexes on permanent tables.
*/
bool
RelationHasUnloggedIndex(Relation rel)
{
List *indexoidlist;
ListCell *indexoidscan;
bool result = false;
indexoidlist = RelationGetIndexList(rel);
foreach(indexoidscan, indexoidlist)
{
Oid indexoid = lfirst_oid(indexoidscan);
HeapTuple tp;
Form_pg_class reltup;
tp = SearchSysCache1(RELOID, ObjectIdGetDatum(indexoid));
if (!HeapTupleIsValid(tp))
elog(ERROR, "cache lookup failed for relation %u", indexoid);
reltup = (Form_pg_class) GETSTRUCT(tp);
if (reltup->relpersistence == RELPERSISTENCE_UNLOGGED)
result = true;
ReleaseSysCache(tp);
if (result == true)
break;
}
list_free(indexoidlist);
return result;
}
/*
* Invalidate (remove) the init file during commit of a transaction that
* changed one or more of the relation cache entries that are kept in the
* local init file.
*
* To be safe against concurrent inspection or rewriting of the init file,
* we must take RelCacheInitLock, then remove the old init file, then send
* the SI messages that include relcache inval for such relations, and then
* release RelCacheInitLock. This serializes the whole affair against
* write_relcache_init_file, so that we can be sure that any other process
* that's concurrently trying to create a new init file won't move an
* already-stale version into place after we unlink. Also, because we unlink
* before sending the SI messages, a backend that's currently starting cannot
* read the now-obsolete init file and then miss the SI messages that will
* force it to update its relcache entries. (This works because the backend
* startup sequence gets into the sinval array before trying to load the init
* file.)
*
* We take the lock and do the unlink in RelationCacheInitFilePreInvalidate,
* then release the lock in RelationCacheInitFilePostInvalidate. Caller must
* send any pending SI messages between those calls.
*
* Notice this deals only with the local init file, not the shared init file.
* The reason is that there can never be a "significant" change to the
* relcache entry of a shared relation; the most that could happen is
* updates of noncritical fields such as relpages/reltuples. So, while
* it's worth updating the shared init file from time to time, it can never
* be invalid enough to make it necessary to remove it.
*/
void
RelationCacheInitFilePreInvalidate(void)
{
char initfilename[MAXPGPATH];
snprintf(initfilename, sizeof(initfilename), "%s/%s",
DatabasePath, RELCACHE_INIT_FILENAME);
LWLockAcquire(RelCacheInitLock, LW_EXCLUSIVE);
if (unlink(initfilename) < 0)
{
/*
* The file might not be there if no backend has been started since
* the last removal. But complain about failures other than ENOENT.
* Fortunately, it's not too late to abort the transaction if we can't
* get rid of the would-be-obsolete init file.
*/
if (errno != ENOENT)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not remove cache file \"%s\": %m",
initfilename)));
}
}
void
RelationCacheInitFilePostInvalidate(void)
{
LWLockRelease(RelCacheInitLock);
}
/*
* Remove the init files during postmaster startup.
*
* We used to keep the init files across restarts, but that is unsafe in PITR
* scenarios, and even in simple crash-recovery cases there are windows for
* the init files to become out-of-sync with the database. So now we just
* remove them during startup and expect the first backend launch to rebuild
* them. Of course, this has to happen in each database of the cluster.
*/
void
RelationCacheInitFileRemove(void)
{
const char *tblspcdir = "pg_tblspc";
DIR *dir;
struct dirent *de;
char path[MAXPGPATH + 10 + sizeof(TABLESPACE_VERSION_DIRECTORY)];
/*
* We zap the shared cache file too. In theory it can't get out of sync
* enough to be a problem, but in data-corruption cases, who knows ...
*/
snprintf(path, sizeof(path), "global/%s",
RELCACHE_INIT_FILENAME);
unlink_initfile(path);
/* Scan everything in the default tablespace */
RelationCacheInitFileRemoveInDir("base");
/* Scan the tablespace link directory to find non-default tablespaces */
dir = AllocateDir(tblspcdir);
while ((de = ReadDirExtended(dir, tblspcdir, LOG)) != NULL)
{
if (strspn(de->d_name, "0123456789") == strlen(de->d_name))
{
/* Scan the tablespace dir for per-database dirs */
snprintf(path, sizeof(path), "%s/%s/%s",
tblspcdir, de->d_name, TABLESPACE_VERSION_DIRECTORY);
RelationCacheInitFileRemoveInDir(path);
}
}
FreeDir(dir);
}
/* Process one per-tablespace directory for RelationCacheInitFileRemove */
static void
RelationCacheInitFileRemoveInDir(const char *tblspcpath)
{
DIR *dir;
struct dirent *de;
char initfilename[MAXPGPATH * 2];
/* Scan the tablespace directory to find per-database directories */
dir = AllocateDir(tblspcpath);
while ((de = ReadDirExtended(dir, tblspcpath, LOG)) != NULL)
{
if (strspn(de->d_name, "0123456789") == strlen(de->d_name))
{
/* Try to remove the init file in each database */
snprintf(initfilename, sizeof(initfilename), "%s/%s/%s",
tblspcpath, de->d_name, RELCACHE_INIT_FILENAME);
unlink_initfile(initfilename);
}
}
FreeDir(dir);
}
static void
unlink_initfile(const char *initfilename)
{
if (unlink(initfilename) < 0)
{
/* It might not be there, but log any error other than ENOENT */
if (errno != ENOENT)
elog(LOG, "could not remove cache file \"%s\": %m", initfilename);
}
}
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