/*-------------------------------------------------------------------------
*
* relcache.c
* POSTGRES relation descriptor cache code
*
* Portions Copyright (c) 1996-2018, 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/tupdesc_details.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/cost.h"
#include "optimizer/prep.h"
#include "optimizer/var.h"
#include "pgstat.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/datum.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 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;
amoptions_function amoptsfn;
relation->rd_options = NULL;
/*
* Look up any AM-specific parse function; fall out if relkind should not
* have options.
*/
switch (relation->rd_rel->relkind)
{
case RELKIND_RELATION:
case RELKIND_TOASTVALUE:
case RELKIND_VIEW:
case RELKIND_MATVIEW:
case RELKIND_PARTITIONED_TABLE:
amoptsfn = NULL;
break;
case RELKIND_INDEX:
case RELKIND_PARTITIONED_INDEX:
amoptsfn = relation->rd_amroutine->amoptions;
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(), amoptsfn);
/*
* 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;
AttrMissing *attrmiss = 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;
int attnum;
attp = (Form_pg_attribute) GETSTRUCT(pg_attribute_tuple);
attnum = attp->attnum;
if (attnum <= 0 || attnum > relation->rd_rel->relnatts)
elog(ERROR, "invalid attribute number %d for %s",
attp->attnum, RelationGetRelationName(relation));
memcpy(TupleDescAttr(relation->rd_att, attnum - 1),
attp,
ATTRIBUTE_FIXED_PART_SIZE);
/* Update constraint/default info */
if (attp->attnotnull)
constr->has_not_null = true;
/* If the column has a default, fill it into the attrdef array */
if (attp->atthasdef)
{
if (attrdef == NULL)
attrdef = (AttrDefault *)
MemoryContextAllocZero(CacheMemoryContext,
relation->rd_rel->relnatts *
sizeof(AttrDefault));
attrdef[ndef].adnum = attnum;
attrdef[ndef].adbin = NULL;
ndef++;
}
/* Likewise for a missing value */
if (attp->atthasmissing)
{
Datum missingval;
bool missingNull;
/* Do we have a missing value? */
missingval = heap_getattr(pg_attribute_tuple,
Anum_pg_attribute_attmissingval,
pg_attribute_desc->rd_att,
&missingNull);
if (!missingNull)
{
/* Yes, fetch from the array */
MemoryContext oldcxt;
bool is_null;
int one = 1;
Datum missval;
if (attrmiss == NULL)
attrmiss = (AttrMissing *)
MemoryContextAllocZero(CacheMemoryContext,
relation->rd_rel->relnatts *
sizeof(AttrMissing));
missval = array_get_element(missingval,
1,
&one,
-1,
attp->attlen,
attp->attbyval,
attp->attalign,
&is_null);
Assert(!is_null);
if (attp->attbyval)
{
/* for copy by val just copy the datum direct */
attrmiss[attnum - 1].ammissing = missval;
}
else
{
/* otherwise copy in the correct context */
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
attrmiss[attnum - 1].ammissing = datumCopy(missval,
attp->attbyval,
attp->attlen);
MemoryContextSwitchTo(oldcxt);
}
attrmiss[attnum - 1].ammissingPresent = true;
}
}
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 ||
attrmiss || 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;
constr->missing = attrmiss;
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 = AllocSetContextCreate(CacheMemoryContext,
"relation rules",
ALLOCSET_SMALL_SIZES);
relation->rd_rulescxt = rulescxt;
MemoryContextCopySetIdentifier(rulescxt,
RelationGetRelationName(relation));
/*
* 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 a complex structure; to avoid complicated logic to
* free individual elements whenever the relcache entry is flushed, we give it
* its own memory context, child of CacheMemoryContext, which can easily be
* deleted on its own. To avoid leaking memory in that context in case of an
* error partway through this function, the context is initially created as a
* child of CurTransactionContext and only re-parented to CacheMemoryContext
* at the end, when no further errors are possible. Also, we don't make this
* context the current context except in very brief code sections, out of fear
* that some of our callees allocate memory on their own which would be leaked
* permanently.
*/
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;
partkeycxt = AllocSetContextCreate(CurTransactionContext,
"partition key",
ALLOCSET_SMALL_SIZES);
MemoryContextCopySetIdentifier(partkeycxt,
RelationGetRelationName(relation));
key = (PartitionKey) MemoryContextAllocZero(partkeycxt,
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; fix
* opfuncids while at it. We don't need to bother with
* canonicalize_qual() though, because partition expressions should be
* in canonical form already (ie, no need for OR-merging or constant
* elimination).
*/
expr = eval_const_expressions(NULL, expr);
fix_opfuncids(expr);
oldcxt = MemoryContextSwitchTo(partkeycxt);
key->partexprs = (List *) copyObject(expr);
MemoryContextSwitchTo(oldcxt);
}
oldcxt = MemoryContextSwitchTo(partkeycxt);
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));
MemoryContextSwitchTo(oldcxt);
/* determine support function number to search for */
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 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
{
if (partexprs_item == NULL)
elog(ERROR, "wrong number of partition key expressions");
key->parttypid[i] = exprType(lfirst(partexprs_item));
key->parttypmod[i] = exprTypmod(lfirst(partexprs_item));
key->parttypcoll[i] = exprCollation(lfirst(partexprs_item));
partexprs_item = lnext(partexprs_item);
}
get_typlenbyvalalign(key->parttypid[i],
&key->parttyplen[i],
&key->parttypbyval[i],
&key->parttypalign[i]);
ReleaseSysCache(opclasstup);
}
ReleaseSysCache(tuple);
/*
* Success --- reparent our context and make the relcache point to the
* newly constructed key
*/
MemoryContextSetParent(partkeycxt, CacheMemoryContext);
relation->rd_partkeycxt = partkeycxt;
relation->rd_partkey = key;
}
/*
* 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 = AllocSetContextCreate(CacheMemoryContext,
"index info",
ALLOCSET_SMALL_SIZES);
relation->rd_indexcxt = indexcxt;
MemoryContextCopySetIdentifier(indexcxt,
RelationGetRelationName(relation));
/*
* 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.
*
* The catalogs this is used for 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 ||
rd->rd_rel->relkind == RELKIND_PARTITIONED_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_rel->relkind == RELKIND_PARTITIONED_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_projindexattr);
bms_free(relation->rd_keyattr);
bms_free(relation->rd_pkattr);
bms_free(relation->rd_idattr);
bms_free(relation->rd_projidx);
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_rel->relkind == RELKIND_PARTITIONED_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_rel->relkind == RELKIND_PARTITIONED_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 (cf. 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);
}
/*
* 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, NULL))
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, NULL))
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 must not use canonicalize_qual, however,
* since these aren't qual expressions.
*/
result = (List *) eval_const_expressions(NULL, (Node *) 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, NULL))
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, false);
/* 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;
}
#define HEURISTIC_MAX_HOT_RECHECK_EXPR_COST 1000
/*
* Check if functional index is projection: index expression returns some subset
* of its argument values. During HOT update check we handle projection indexes
* differently: instead of checking if any of attributes used in indexed
* expression were updated, we calculate and compare values of index expression
* for old and new tuple values.
*
* Decision made by this function is based on two sources:
* 1. Calculated cost of index expression: if greater than some heuristic limit
then extra comparison of index expression values is expected to be too
expensive, so we don't attempt it by default.
* 2. "recheck_on_update" index option explicitly set by user, which overrides 1)
*/
static bool IsProjectionFunctionalIndex(Relation index, IndexInfo* ii)
{
bool is_projection = false;
if (ii->ii_Expressions)
{
HeapTuple tuple;
Datum reloptions;
bool isnull;
QualCost index_expr_cost;
/* by default functional index is considered as non-injective */
is_projection = true;
cost_qual_eval(&index_expr_cost, ii->ii_Expressions, NULL);
/*
* If index expression is too expensive, then disable projection
* optimization, because extra evaluation of index expression is
* expected to be more expensive than index update. Currently the
* projection optimization has to calculate index expression twice
* when the value of index expression has not changed and three times
* when values differ because the expression is recalculated when
* inserting a new index entry for the changed value.
*/
if ((index_expr_cost.startup + index_expr_cost.per_tuple) >
HEURISTIC_MAX_HOT_RECHECK_EXPR_COST)
is_projection = false;
tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(RelationGetRelid(index)));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", RelationGetRelid(index));
reloptions = SysCacheGetAttr(RELOID, tuple,
Anum_pg_class_reloptions, &isnull);
if (!isnull)
{
GenericIndexOpts *idxopts;
idxopts = (GenericIndexOpts *) index_generic_reloptions(reloptions, false);
if (idxopts != NULL)
{
is_projection = idxopts->recheck_on_update;
pfree(idxopts);
}
}
ReleaseSysCache(tuple);
}
return is_projection;
}
/*
* 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; /* columns used in non-projection indexes */
Bitmapset *projindexattrs; /* columns used in projection indexes */
Bitmapset *uindexattrs; /* columns in unique indexes */
Bitmapset *pkindexattrs; /* columns in the primary index */
Bitmapset *idindexattrs; /* columns in the replica identity */
Bitmapset *projindexes; /* projection indexes */
List *indexoidlist;
List *newindexoidlist;
Oid relpkindex;
Oid relreplindex;
ListCell *l;
MemoryContext oldcxt;
int indexno;
/* Quick exit if we already computed the result. */
if (relation->rd_indexattr != NULL)
{
switch (attrKind)
{
case INDEX_ATTR_BITMAP_HOT:
return bms_copy(relation->rd_indexattr);
case INDEX_ATTR_BITMAP_PROJ:
return bms_copy(relation->rd_projindexattr);
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;
projindexattrs = NULL;
uindexattrs = NULL;
pkindexattrs = NULL;
idindexattrs = NULL;
projindexes = NULL;
indexno = 0;
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 attributes used in expressions, too */
if (IsProjectionFunctionalIndex(indexDesc, indexInfo))
{
projindexes = bms_add_member(projindexes, indexno);
pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &projindexattrs);
}
else
{
/* 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);
indexno += 1;
}
/*
* 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);
bms_free(projindexattrs);
bms_free(projindexes);
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_projindexattr);
relation->rd_projindexattr = 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;
bms_free(relation->rd_projidx);
relation->rd_projidx = 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);
relation->rd_projindexattr = bms_copy(projindexattrs);
relation->rd_projidx = bms_copy(projindexes);
MemoryContextSwitchTo(oldcxt);
/* We return our original working copy for caller to play with */
switch (attrKind)
{
case INDEX_ATTR_BITMAP_HOT:
return indexattrs;
case INDEX_ATTR_BITMAP_PROJ:
return projindexattrs;
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_attname(RelationGetRelid(rel), attnum, false);
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. Note we explicitly ignore
* partitioned indexes here.
*/
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 = AllocSetContextCreate(CacheMemoryContext,
"index info",
ALLOCSET_SMALL_SIZES);
rel->rd_indexcxt = indexcxt;
MemoryContextCopySetIdentifier(indexcxt,
RelationGetRelationName(rel));
/*
* 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_projindexattr = NULL;
rel->rd_keyattr = NULL;
rel->rd_pkattr = NULL;
rel->rd_idattr = NULL;
rel->rd_projidx = 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. Note we explicitly ignore
* partitioned indexes here.
*/
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);
}
}