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9db4b9da2801ed94c8f209c807e654c139dc1d7e
postgres/src/include/utils/rel.h
Noah Misch 9db4b9da28 Skip WAL for new relfilenodes, under wal_level=minimal. 
Until now, only selected bulk operations (e.g. COPY) did this.  If a
given relfilenode received both a WAL-skipping COPY and a WAL-logged
operation (e.g. INSERT), recovery could lose tuples from the COPY.  See
src/backend/access/transam/README section "Skipping WAL for New
RelFileNode" for the new coding rules.  Maintainers of table access
methods should examine that section.

To maintain data durability, just before commit, we choose between an
fsync of the relfilenode and copying its contents to WAL.  A new GUC,
wal_skip_threshold, guides that choice.  If this change slows a workload
that creates small, permanent relfilenodes under wal_level=minimal, try
adjusting wal_skip_threshold.  Users setting a timeout on COMMIT may
need to adjust that timeout, and log_min_duration_statement analysis
will reflect time consumption moving to COMMIT from commands like COPY.

Internally, this requires a reliable determination of whether
RollbackAndReleaseCurrentSubTransaction() would unlink a relation's
current relfilenode.  Introduce rd_firstRelfilenodeSubid.  Amend the
specification of rd_createSubid such that the field is zero when a new
rel has an old rd_node.  Make relcache.c retain entries for certain
dropped relations until end of transaction.

Back-patch to 9.5 (all supported versions).  This introduces a new WAL
record type, XLOG_GIST_ASSIGN_LSN, without bumping XLOG_PAGE_MAGIC.  As
always, update standby systems before master systems.  This changes
sizeof(RelationData) and sizeof(IndexStmt), breaking binary
compatibility for affected extensions.  (The most recent commit to
affect the same class of extensions was
089e4d405d0f3b94c74a2c6a54357a84a681754b.)

Kyotaro Horiguchi, reviewed (in earlier, similar versions) by Robert
Haas.  Heikki Linnakangas and Michael Paquier implemented earlier
designs that materially clarified the problem.  Reviewed, in earlier
designs, by Andrew Dunstan, Andres Freund, Alvaro Herrera, Tom Lane,
Fujii Masao, and Simon Riggs.  Reported by Martijn van Oosterhout.

Discussion: https://postgr.es/m/20150702220524.GA9392@svana.org
2020-03-21 09:38:36 -07:00

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/*-------------------------------------------------------------------------
*
* rel.h
* POSTGRES relation descriptor (a/k/a relcache entry) definitions.
*
*
* Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/utils/rel.h
*
*-------------------------------------------------------------------------
*/
#ifndef REL_H
#define REL_H
#include "access/tupdesc.h"
#include "access/xlog.h"
#include "catalog/pg_am.h"
#include "catalog/pg_class.h"
#include "catalog/pg_index.h"
#include "fmgr.h"
#include "nodes/bitmapset.h"
#include "rewrite/prs2lock.h"
#include "storage/block.h"
#include "storage/relfilenode.h"
#include "utils/relcache.h"
#include "utils/reltrigger.h"
/*
* LockRelId and LockInfo really belong to lmgr.h, but it's more convenient
* to declare them here so we can have a LockInfoData field in a Relation.
*/
typedef struct LockRelId
{
Oid relId; /* a relation identifier */
Oid dbId; /* a database identifier */
} LockRelId;
typedef struct LockInfoData
{
LockRelId lockRelId;
} LockInfoData;
typedef LockInfoData *LockInfo;
/*
* Cached lookup information for the frequently used index access method
* functions, defined by the pg_am row associated with an index relation.
*/
typedef struct RelationAmInfo
{
FmgrInfo aminsert;
FmgrInfo ambeginscan;
FmgrInfo amgettuple;
FmgrInfo amgetbitmap;
FmgrInfo amrescan;
FmgrInfo amendscan;
FmgrInfo ammarkpos;
FmgrInfo amrestrpos;
FmgrInfo amcanreturn;
} RelationAmInfo;
/*
* Here are the contents of a relation cache entry.
*/
typedef struct RelationData
{
RelFileNode rd_node; /* relation physical identifier */
/* use "struct" here to avoid needing to include smgr.h: */
struct SMgrRelationData *rd_smgr; /* cached file handle, or NULL */
int rd_refcnt; /* reference count */
BackendId rd_backend; /* owning backend id, if temporary relation */
bool rd_islocaltemp; /* rel is a temp rel of this session */
bool rd_isnailed; /* rel is nailed in cache */
bool rd_isvalid; /* relcache entry is valid */
char rd_indexvalid; /* state of rd_indexlist: 0 = not valid, 1 =
* valid, 2 = temporarily forced */
/*----------
* rd_createSubid is the ID of the highest subtransaction the rel has
* survived into or zero if the rel or its rd_node was created before the
* current top transaction. (IndexStmt.oldNode leads to the case of a new
* rel with an old rd_node.) rd_firstRelfilenodeSubid is the ID of the
* highest subtransaction an rd_node change has survived into or zero if
* rd_node matches the value it had at the start of the current top
* transaction. (Rolling back the subtransaction that
* rd_firstRelfilenodeSubid denotes would restore rd_node to the value it
* had at the start of the current top transaction. Rolling back any
* lower subtransaction would not.) Their accuracy is critical to
* RelationNeedsWAL().
*
* rd_newRelfilenodeSubid is the ID of the highest subtransaction the
* most-recent relfilenode change has survived into or zero if not changed
* in the current transaction (or we have forgotten changing it). This
* field is accurate when non-zero, but it can be zero when a relation has
* multiple new relfilenodes within a single transaction, with one of them
* occurring in a subsequently aborted subtransaction, e.g.
* BEGIN;
* TRUNCATE t;
* SAVEPOINT save;
* TRUNCATE t;
* ROLLBACK TO save;
* -- rd_newRelfilenodeSubid is now forgotten
*
* If every rd_*Subid field is zero, they are read-only outside
* relcache.c. Files that trigger rd_node changes by updating
* pg_class.reltablespace and/or pg_class.relfilenode call
* RelationAssumeNewRelfilenode() to update rd_*Subid.
*
* rd_droppedSubid is the ID of the highest subtransaction that a drop of
* the rel has survived into. In entries visible outside relcache.c, this
* is always zero.
*/
SubTransactionId rd_createSubid; /* rel was created in current xact */
SubTransactionId rd_newRelfilenodeSubid; /* highest subxact changing
* rd_node to current value */
/* see end for rd_firstRelfilenodeSubid and rd_droppedSubid */
Form_pg_class rd_rel; /* RELATION tuple */
TupleDesc rd_att; /* tuple descriptor */
Oid rd_id; /* relation's object id */
LockInfoData rd_lockInfo; /* lock mgr's info for locking relation */
RuleLock *rd_rules; /* rewrite rules */
MemoryContext rd_rulescxt; /* private memory cxt for rd_rules, if any */
TriggerDesc *trigdesc; /* Trigger info, or NULL if rel has none */
/* use "struct" here to avoid needing to include rowsecurity.h: */
struct RowSecurityDesc *rd_rsdesc; /* row security policies, or NULL */
/* data managed by RelationGetIndexList: */
List *rd_indexlist; /* list of OIDs of indexes on relation */
Oid rd_oidindex; /* OID of unique index on OID, if any */
Oid rd_replidindex; /* OID of replica identity index, if any */
/* data managed by RelationGetIndexAttrBitmap: */
Bitmapset *rd_indexattr; /* identifies columns used in indexes */
Bitmapset *rd_keyattr; /* cols that can be ref'd by foreign keys */
Bitmapset *rd_idattr; /* included in replica identity index */
/*
* rd_options is set whenever rd_rel is loaded into the relcache entry.
* Note that you can NOT look into rd_rel for this data. NULL means "use
* defaults".
*/
bytea *rd_options; /* parsed pg_class.reloptions */
/* These are non-NULL only for an index relation: */
Form_pg_index rd_index; /* pg_index tuple describing this index */
/* use "struct" here to avoid needing to include htup.h: */
struct HeapTupleData *rd_indextuple; /* all of pg_index tuple */
Form_pg_am rd_am; /* pg_am tuple for index's AM */
/*
* index access support info (used only for an index relation)
*
* Note: only default support procs for each opclass are cached, namely
* those with lefttype and righttype equal to the opclass's opcintype. The
* arrays are indexed by support function number, which is a sufficient
* identifier given that restriction.
*
* Note: rd_amcache is available for index AMs to cache private data about
* an index. This must be just a cache since it may get reset at any time
* (in particular, it will get reset by a relcache inval message for the
* index). If used, it must point to a single memory chunk palloc'd in
* rd_indexcxt. A relcache reset will include freeing that chunk and
* setting rd_amcache = NULL.
*/
MemoryContext rd_indexcxt; /* private memory cxt for this stuff */
RelationAmInfo *rd_aminfo; /* lookup info for funcs found in pg_am */
Oid *rd_opfamily; /* OIDs of op families for each index col */
Oid *rd_opcintype; /* OIDs of opclass declared input data types */
RegProcedure *rd_support; /* OIDs of support procedures */
FmgrInfo *rd_supportinfo; /* lookup info for support procedures */
int16 *rd_indoption; /* per-column AM-specific flags */
List *rd_indexprs; /* index expression trees, if any */
List *rd_indpred; /* index predicate tree, if any */
Oid *rd_exclops; /* OIDs of exclusion operators, if any */
Oid *rd_exclprocs; /* OIDs of exclusion ops' procs, if any */
uint16 *rd_exclstrats; /* exclusion ops' strategy numbers, if any */
void *rd_amcache; /* available for use by index AM */
Oid *rd_indcollation; /* OIDs of index collations */
/*
* foreign-table support
*
* rd_fdwroutine must point to a single memory chunk palloc'd in
* CacheMemoryContext. It will be freed and reset to NULL on a relcache
* reset.
*/
/* use "struct" here to avoid needing to include fdwapi.h: */
struct FdwRoutine *rd_fdwroutine; /* cached function pointers, or NULL */
/*
* Hack for CLUSTER, rewriting ALTER TABLE, etc: when writing a new
* version of a table, we need to make any toast pointers inserted into it
* have the existing toast table's OID, not the OID of the transient toast
* table. If rd_toastoid isn't InvalidOid, it is the OID to place in
* toast pointers inserted into this rel. (Note it's set on the new
* version of the main heap, not the toast table itself.) This also
* causes toast_save_datum() to try to preserve toast value OIDs.
*/
Oid rd_toastoid; /* Real TOAST table's OID, or InvalidOid */
/* use "struct" here to avoid needing to include pgstat.h: */
struct PgStat_TableStatus *pgstat_info; /* statistics collection area */
SubTransactionId rd_firstRelfilenodeSubid; /* highest subxact changing
* rd_node to any value */
SubTransactionId rd_droppedSubid; /* dropped with another Subid set */
} RelationData;
/*
* StdRdOptions
* Standard contents of rd_options for heaps and generic indexes.
*
* RelationGetFillFactor() and RelationGetTargetPageFreeSpace() can only
* be applied to relations that use this format or a superset for
* private options data.
*/
/* autovacuum-related reloptions. */
typedef struct AutoVacOpts
{
bool enabled;
int vacuum_threshold;
int analyze_threshold;
int vacuum_cost_delay;
int vacuum_cost_limit;
int freeze_min_age;
int freeze_max_age;
int freeze_table_age;
int multixact_freeze_min_age;
int multixact_freeze_max_age;
int multixact_freeze_table_age;
int log_min_duration;
float8 vacuum_scale_factor;
float8 analyze_scale_factor;
} AutoVacOpts;
typedef struct StdRdOptions
{
int32 vl_len_; /* varlena header (do not touch directly!) */
int fillfactor; /* page fill factor in percent (0..100) */
AutoVacOpts autovacuum; /* autovacuum-related options */
bool user_catalog_table; /* use as an additional catalog
* relation */
} StdRdOptions;
#define HEAP_MIN_FILLFACTOR 10
#define HEAP_DEFAULT_FILLFACTOR 100
/*
* RelationGetFillFactor
* Returns the relation's fillfactor. Note multiple eval of argument!
*/
#define RelationGetFillFactor(relation, defaultff) \
((relation)->rd_options ? \
((StdRdOptions *) (relation)->rd_options)->fillfactor : (defaultff))
/*
* RelationGetTargetPageUsage
* Returns the relation's desired space usage per page in bytes.
*/
#define RelationGetTargetPageUsage(relation, defaultff) \
(BLCKSZ * RelationGetFillFactor(relation, defaultff) / 100)
/*
* RelationGetTargetPageFreeSpace
* Returns the relation's desired freespace per page in bytes.
*/
#define RelationGetTargetPageFreeSpace(relation, defaultff) \
(BLCKSZ * (100 - RelationGetFillFactor(relation, defaultff)) / 100)
/*
* RelationIsUsedAsCatalogTable
* Returns whether the relation should be treated as a catalog table
* from the pov of logical decoding. Note multiple eval or argument!
*/
#define RelationIsUsedAsCatalogTable(relation) \
((relation)->rd_options && \
((relation)->rd_rel->relkind == RELKIND_RELATION || \
(relation)->rd_rel->relkind == RELKIND_MATVIEW) ? \
((StdRdOptions *) (relation)->rd_options)->user_catalog_table : false)
/*
* ViewOptions
* Contents of rd_options for views
*/
typedef struct ViewOptions
{
int32 vl_len_; /* varlena header (do not touch directly!) */
bool security_barrier;
int check_option_offset;
} ViewOptions;
/*
* RelationIsSecurityView
* Returns whether the relation is security view, or not. Note multiple
* eval of argument!
*/
#define RelationIsSecurityView(relation) \
((relation)->rd_options ? \
((ViewOptions *) (relation)->rd_options)->security_barrier : false)
/*
* RelationHasCheckOption
* Returns true if the relation is a view defined with either the local
* or the cascaded check option. Note multiple eval of argument!
*/
#define RelationHasCheckOption(relation) \
((relation)->rd_options && \
((ViewOptions *) (relation)->rd_options)->check_option_offset != 0)
/*
* RelationHasLocalCheckOption
* Returns true if the relation is a view defined with the local check
* option. Note multiple eval of argument!
*/
#define RelationHasLocalCheckOption(relation) \
((relation)->rd_options && \
((ViewOptions *) (relation)->rd_options)->check_option_offset != 0 ? \
strcmp((char *) (relation)->rd_options + \
((ViewOptions *) (relation)->rd_options)->check_option_offset, \
"local") == 0 : false)
/*
* RelationHasCascadedCheckOption
* Returns true if the relation is a view defined with the cascaded check
* option. Note multiple eval of argument!
*/
#define RelationHasCascadedCheckOption(relation) \
((relation)->rd_options && \
((ViewOptions *) (relation)->rd_options)->check_option_offset != 0 ? \
strcmp((char *) (relation)->rd_options + \
((ViewOptions *) (relation)->rd_options)->check_option_offset, \
"cascaded") == 0 : false)
/*
* RelationIsValid
* True iff relation descriptor is valid.
*/
#define RelationIsValid(relation) PointerIsValid(relation)
#define InvalidRelation ((Relation) NULL)
/*
* RelationHasReferenceCountZero
* True iff relation reference count is zero.
*
* Note:
* Assumes relation descriptor is valid.
*/
#define RelationHasReferenceCountZero(relation) \
((bool)((relation)->rd_refcnt == 0))
/*
* RelationGetForm
* Returns pg_class tuple for a relation.
*
* Note:
* Assumes relation descriptor is valid.
*/
#define RelationGetForm(relation) ((relation)->rd_rel)
/*
* RelationGetRelid
* Returns the OID of the relation
*/
#define RelationGetRelid(relation) ((relation)->rd_id)
/*
* RelationGetNumberOfAttributes
* Returns the number of attributes in a relation.
*/
#define RelationGetNumberOfAttributes(relation) ((relation)->rd_rel->relnatts)
/*
* RelationGetDescr
* Returns tuple descriptor for a relation.
*/
#define RelationGetDescr(relation) ((relation)->rd_att)
/*
* RelationGetRelationName
* Returns the rel's name.
*
* Note that the name is only unique within the containing namespace.
*/
#define RelationGetRelationName(relation) \
(NameStr((relation)->rd_rel->relname))
/*
* RelationGetNamespace
* Returns the rel's namespace OID.
*/
#define RelationGetNamespace(relation) \
((relation)->rd_rel->relnamespace)
/*
* RelationIsMapped
* True if the relation uses the relfilenode map.
*
* NB: this is only meaningful for relkinds that have storage, else it
* will misleadingly say "true".
*/
#define RelationIsMapped(relation) \
((relation)->rd_rel->relfilenode == InvalidOid)
/*
* RelationOpenSmgr
* Open the relation at the smgr level, if not already done.
*/
#define RelationOpenSmgr(relation) \
do { \
if ((relation)->rd_smgr == NULL) \
smgrsetowner(&((relation)->rd_smgr), smgropen((relation)->rd_node, (relation)->rd_backend)); \
} while (0)
/*
* RelationCloseSmgr
* Close the relation at the smgr level, if not already done.
*
* Note: smgrclose should unhook from owner pointer, hence the Assert.
*/
#define RelationCloseSmgr(relation) \
do { \
if ((relation)->rd_smgr != NULL) \
{ \
smgrclose((relation)->rd_smgr); \
Assert((relation)->rd_smgr == NULL); \
} \
} while (0)
/*
* RelationGetTargetBlock
* Fetch relation's current insertion target block.
*
* Returns InvalidBlockNumber if there is no current target block. Note
* that the target block status is discarded on any smgr-level invalidation.
*/
#define RelationGetTargetBlock(relation) \
( (relation)->rd_smgr != NULL ? (relation)->rd_smgr->smgr_targblock : InvalidBlockNumber )
/*
* RelationSetTargetBlock
* Set relation's current insertion target block.
*/
#define RelationSetTargetBlock(relation, targblock) \
do { \
RelationOpenSmgr(relation); \
(relation)->rd_smgr->smgr_targblock = (targblock); \
} while (0)
/*
* RelationNeedsWAL
* True if relation needs WAL.
*
* Returns false if wal_level = minimal and this relation is created or
* truncated in the current transaction. See "Skipping WAL for New
* RelFileNode" in src/backend/access/transam/README.
*/
#define RelationNeedsWAL(relation) \
((relation)->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT && \
(XLogIsNeeded() || \
(relation->rd_createSubid == InvalidSubTransactionId && \
relation->rd_firstRelfilenodeSubid == InvalidSubTransactionId)))
/*
* RelationUsesLocalBuffers
* True if relation's pages are stored in local buffers.
*/
#define RelationUsesLocalBuffers(relation) \
((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
/*
* RELATION_IS_LOCAL
* If a rel is either temp or newly created in the current transaction,
* it can be assumed to be accessible only to the current backend.
* This is typically used to decide that we can skip acquiring locks.
*
* Beware of multiple eval of argument
*/
#define RELATION_IS_LOCAL(relation) \
((relation)->rd_islocaltemp || \
(relation)->rd_createSubid != InvalidSubTransactionId)
/*
* RELATION_IS_OTHER_TEMP
* Test for a temporary relation that belongs to some other session.
*
* Beware of multiple eval of argument
*/
#define RELATION_IS_OTHER_TEMP(relation) \
((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP && \
!(relation)->rd_islocaltemp)
/*
* RelationIsScannable
* Currently can only be false for a materialized view which has not been
* populated by its query. This is likely to get more complicated later,
* so use a macro which looks like a function.
*/
#define RelationIsScannable(relation) ((relation)->rd_rel->relispopulated)
/*
* RelationIsPopulated
* Currently, we don't physically distinguish the "populated" and
* "scannable" properties of matviews, but that may change later.
* Hence, use the appropriate one of these macros in code tests.
*/
#define RelationIsPopulated(relation) ((relation)->rd_rel->relispopulated)
/*
* RelationIsAccessibleInLogicalDecoding
* True if we need to log enough information to have access via
* decoding snapshot.
*/
#define RelationIsAccessibleInLogicalDecoding(relation) \
(XLogLogicalInfoActive() && \
RelationNeedsWAL(relation) && \
(IsCatalogRelation(relation) || RelationIsUsedAsCatalogTable(relation)))
/*
* RelationIsLogicallyLogged
* True if we need to log enough information to extract the data from the
* WAL stream.
*
* We don't log information for unlogged tables (since they don't WAL log
* anyway) and for system tables (their content is hard to make sense of, and
* it would complicate decoding slightly for little gain). Note that we *do*
* log information for user defined catalog tables since they presumably are
* interesting to the user...
*/
#define RelationIsLogicallyLogged(relation) \
(XLogLogicalInfoActive() && \
RelationNeedsWAL(relation) && \
!IsCatalogRelation(relation))
/* routines in utils/cache/relcache.c */
extern void RelationIncrementReferenceCount(Relation rel);
extern void RelationDecrementReferenceCount(Relation rel);
#endif /* REL_H */
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