You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
postgres/src/include/utils/syscache.h

137 lines
5.2 KiB

/*-------------------------------------------------------------------------
*
* syscache.h
* System catalog cache definitions.
*
* See also lsyscache.h, which provides convenience routines for
* common cache-lookup operations.
*
* Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/utils/syscache.h
*
*-------------------------------------------------------------------------
*/
#ifndef SYSCACHE_H
#define SYSCACHE_H
#include "access/attnum.h"
#include "access/htup.h"
Use a safer method for determining whether relcache init file is stale. When we invalidate the relcache entry for a system catalog or index, we must also delete the relcache "init file" if the init file contains a copy of that rel's entry. The old way of doing this relied on a specially maintained list of the OIDs of relations present in the init file: we made the list either when reading the file in, or when writing the file out. The problem is that when writing the file out, we included only rels present in our local relcache, which might have already suffered some deletions due to relcache inval events. In such cases we correctly decided not to overwrite the real init file with incomplete data --- but we still used the incomplete initFileRelationIds list for the rest of the current session. This could result in wrong decisions about whether the session's own actions require deletion of the init file, potentially allowing an init file created by some other concurrent session to be left around even though it's been made stale. Since we don't support changing the schema of a system catalog at runtime, the only likely scenario in which this would cause a problem in the field involves a "vacuum full" on a catalog concurrently with other activity, and even then it's far from easy to provoke. Remarkably, this has been broken since 2002 (in commit 786340441706ac1957a031f11ad1c2e5b6e18314), but we had never seen a reproducible test case until recently. If it did happen in the field, the symptoms would probably involve unexpected "cache lookup failed" errors to begin with, then "could not open file" failures after the next checkpoint, as all accesses to the affected catalog stopped working. Recovery would require manually removing the stale "pg_internal.init" file. To fix, get rid of the initFileRelationIds list, and instead consult syscache.c's list of relations used in catalog caches to decide whether a relation is included in the init file. This should be a tad more efficient anyway, since we're replacing linear search of a list with ~100 entries with a binary search. It's a bit ugly that the init file contents are now so directly tied to the catalog caches, but in practice that won't make much difference. Back-patch to all supported branches.
11 years ago
/* we intentionally do not include utils/catcache.h here */
#include "catalog/syscache_ids.h" /* IWYU pragma: export */
extern void InitCatalogCache(void);
extern void InitCatalogCachePhase2(void);
extern HeapTuple SearchSysCache(int cacheId,
Datum key1, Datum key2, Datum key3, Datum key4);
Improve sys/catcache performance. The following are the individual improvements: 1) Avoidance of FunctionCallInfo based function calls, replaced by more efficient functions with a native C argument interface. 2) Don't extract columns from a cache entry's tuple whenever matching entries - instead store them as a Datum array. This also allows to get rid of having to build dummy tuples for negative & list entries, and of a hack for dealing with cstring vs. text weirdness. 3) Reorder members of catcache.h struct, so imortant entries are more likely to be on one cacheline. 4) Allowing the compiler to specialize critical SearchCatCache for a specific number of attributes allows to unroll loops and avoid other nkeys dependant initialization. 5) Only initializing the ScanKey when necessary, i.e. catcache misses, greatly reduces cache unnecessary cpu cache misses. 6) Split of the cache-miss case from the hash lookup, reducing stack allocations etc in the common case. 7) CatCTup and their corresponding heaptuple are allocated in one piece. This results in making cache lookups themselves roughly three times as fast - full-system benchmarks obviously improve less than that. I've also evaluated further techniques: - replace open coded hash with simplehash - the list walk right now shows up in profiles. Unfortunately it's not easy to do so safely as an entry's memory location can change at various times, which doesn't work well with the refcounting and cache invalidation. - Cacheline-aligning CatCTup entries - helps some with performance, but the win isn't big and the code for it is ugly, because the tuples have to be freed as well. - add more proper functions, rather than macros for SearchSysCacheCopyN etc., but right now they don't show up in profiles. The reason the macro wrapper for syscache.c/h have to be changed, rather than just catcache, is that doing otherwise would require exposing the SysCache array to the outside. That might be a good idea anyway, but it's for another day. Author: Andres Freund Reviewed-By: Robert Haas Discussion: https://postgr.es/m/20170914061207.zxotvyopetm7lrrp@alap3.anarazel.de
8 years ago
/*
* The use of argument specific numbers is encouraged. They're faster, and
* insulates the caller from changes in the maximum number of keys.
*/
extern HeapTuple SearchSysCache1(int cacheId,
Datum key1);
Improve sys/catcache performance. The following are the individual improvements: 1) Avoidance of FunctionCallInfo based function calls, replaced by more efficient functions with a native C argument interface. 2) Don't extract columns from a cache entry's tuple whenever matching entries - instead store them as a Datum array. This also allows to get rid of having to build dummy tuples for negative & list entries, and of a hack for dealing with cstring vs. text weirdness. 3) Reorder members of catcache.h struct, so imortant entries are more likely to be on one cacheline. 4) Allowing the compiler to specialize critical SearchCatCache for a specific number of attributes allows to unroll loops and avoid other nkeys dependant initialization. 5) Only initializing the ScanKey when necessary, i.e. catcache misses, greatly reduces cache unnecessary cpu cache misses. 6) Split of the cache-miss case from the hash lookup, reducing stack allocations etc in the common case. 7) CatCTup and their corresponding heaptuple are allocated in one piece. This results in making cache lookups themselves roughly three times as fast - full-system benchmarks obviously improve less than that. I've also evaluated further techniques: - replace open coded hash with simplehash - the list walk right now shows up in profiles. Unfortunately it's not easy to do so safely as an entry's memory location can change at various times, which doesn't work well with the refcounting and cache invalidation. - Cacheline-aligning CatCTup entries - helps some with performance, but the win isn't big and the code for it is ugly, because the tuples have to be freed as well. - add more proper functions, rather than macros for SearchSysCacheCopyN etc., but right now they don't show up in profiles. The reason the macro wrapper for syscache.c/h have to be changed, rather than just catcache, is that doing otherwise would require exposing the SysCache array to the outside. That might be a good idea anyway, but it's for another day. Author: Andres Freund Reviewed-By: Robert Haas Discussion: https://postgr.es/m/20170914061207.zxotvyopetm7lrrp@alap3.anarazel.de
8 years ago
extern HeapTuple SearchSysCache2(int cacheId,
Datum key1, Datum key2);
Improve sys/catcache performance. The following are the individual improvements: 1) Avoidance of FunctionCallInfo based function calls, replaced by more efficient functions with a native C argument interface. 2) Don't extract columns from a cache entry's tuple whenever matching entries - instead store them as a Datum array. This also allows to get rid of having to build dummy tuples for negative & list entries, and of a hack for dealing with cstring vs. text weirdness. 3) Reorder members of catcache.h struct, so imortant entries are more likely to be on one cacheline. 4) Allowing the compiler to specialize critical SearchCatCache for a specific number of attributes allows to unroll loops and avoid other nkeys dependant initialization. 5) Only initializing the ScanKey when necessary, i.e. catcache misses, greatly reduces cache unnecessary cpu cache misses. 6) Split of the cache-miss case from the hash lookup, reducing stack allocations etc in the common case. 7) CatCTup and their corresponding heaptuple are allocated in one piece. This results in making cache lookups themselves roughly three times as fast - full-system benchmarks obviously improve less than that. I've also evaluated further techniques: - replace open coded hash with simplehash - the list walk right now shows up in profiles. Unfortunately it's not easy to do so safely as an entry's memory location can change at various times, which doesn't work well with the refcounting and cache invalidation. - Cacheline-aligning CatCTup entries - helps some with performance, but the win isn't big and the code for it is ugly, because the tuples have to be freed as well. - add more proper functions, rather than macros for SearchSysCacheCopyN etc., but right now they don't show up in profiles. The reason the macro wrapper for syscache.c/h have to be changed, rather than just catcache, is that doing otherwise would require exposing the SysCache array to the outside. That might be a good idea anyway, but it's for another day. Author: Andres Freund Reviewed-By: Robert Haas Discussion: https://postgr.es/m/20170914061207.zxotvyopetm7lrrp@alap3.anarazel.de
8 years ago
extern HeapTuple SearchSysCache3(int cacheId,
Datum key1, Datum key2, Datum key3);
Improve sys/catcache performance. The following are the individual improvements: 1) Avoidance of FunctionCallInfo based function calls, replaced by more efficient functions with a native C argument interface. 2) Don't extract columns from a cache entry's tuple whenever matching entries - instead store them as a Datum array. This also allows to get rid of having to build dummy tuples for negative & list entries, and of a hack for dealing with cstring vs. text weirdness. 3) Reorder members of catcache.h struct, so imortant entries are more likely to be on one cacheline. 4) Allowing the compiler to specialize critical SearchCatCache for a specific number of attributes allows to unroll loops and avoid other nkeys dependant initialization. 5) Only initializing the ScanKey when necessary, i.e. catcache misses, greatly reduces cache unnecessary cpu cache misses. 6) Split of the cache-miss case from the hash lookup, reducing stack allocations etc in the common case. 7) CatCTup and their corresponding heaptuple are allocated in one piece. This results in making cache lookups themselves roughly three times as fast - full-system benchmarks obviously improve less than that. I've also evaluated further techniques: - replace open coded hash with simplehash - the list walk right now shows up in profiles. Unfortunately it's not easy to do so safely as an entry's memory location can change at various times, which doesn't work well with the refcounting and cache invalidation. - Cacheline-aligning CatCTup entries - helps some with performance, but the win isn't big and the code for it is ugly, because the tuples have to be freed as well. - add more proper functions, rather than macros for SearchSysCacheCopyN etc., but right now they don't show up in profiles. The reason the macro wrapper for syscache.c/h have to be changed, rather than just catcache, is that doing otherwise would require exposing the SysCache array to the outside. That might be a good idea anyway, but it's for another day. Author: Andres Freund Reviewed-By: Robert Haas Discussion: https://postgr.es/m/20170914061207.zxotvyopetm7lrrp@alap3.anarazel.de
8 years ago
extern HeapTuple SearchSysCache4(int cacheId,
Datum key1, Datum key2, Datum key3, Datum key4);
Improve sys/catcache performance. The following are the individual improvements: 1) Avoidance of FunctionCallInfo based function calls, replaced by more efficient functions with a native C argument interface. 2) Don't extract columns from a cache entry's tuple whenever matching entries - instead store them as a Datum array. This also allows to get rid of having to build dummy tuples for negative & list entries, and of a hack for dealing with cstring vs. text weirdness. 3) Reorder members of catcache.h struct, so imortant entries are more likely to be on one cacheline. 4) Allowing the compiler to specialize critical SearchCatCache for a specific number of attributes allows to unroll loops and avoid other nkeys dependant initialization. 5) Only initializing the ScanKey when necessary, i.e. catcache misses, greatly reduces cache unnecessary cpu cache misses. 6) Split of the cache-miss case from the hash lookup, reducing stack allocations etc in the common case. 7) CatCTup and their corresponding heaptuple are allocated in one piece. This results in making cache lookups themselves roughly three times as fast - full-system benchmarks obviously improve less than that. I've also evaluated further techniques: - replace open coded hash with simplehash - the list walk right now shows up in profiles. Unfortunately it's not easy to do so safely as an entry's memory location can change at various times, which doesn't work well with the refcounting and cache invalidation. - Cacheline-aligning CatCTup entries - helps some with performance, but the win isn't big and the code for it is ugly, because the tuples have to be freed as well. - add more proper functions, rather than macros for SearchSysCacheCopyN etc., but right now they don't show up in profiles. The reason the macro wrapper for syscache.c/h have to be changed, rather than just catcache, is that doing otherwise would require exposing the SysCache array to the outside. That might be a good idea anyway, but it's for another day. Author: Andres Freund Reviewed-By: Robert Haas Discussion: https://postgr.es/m/20170914061207.zxotvyopetm7lrrp@alap3.anarazel.de
8 years ago
extern void ReleaseSysCache(HeapTuple tuple);
extern HeapTuple SearchSysCacheLocked1(int cacheId,
Datum key1);
/* convenience routines */
extern HeapTuple SearchSysCacheCopy(int cacheId,
Datum key1, Datum key2, Datum key3, Datum key4);
extern HeapTuple SearchSysCacheLockedCopy1(int cacheId,
Datum key1);
extern bool SearchSysCacheExists(int cacheId,
Datum key1, Datum key2, Datum key3, Datum key4);
extern Oid GetSysCacheOid(int cacheId, AttrNumber oidcol,
Datum key1, Datum key2, Datum key3, Datum key4);
extern HeapTuple SearchSysCacheAttName(Oid relid, const char *attname);
extern HeapTuple SearchSysCacheCopyAttName(Oid relid, const char *attname);
extern bool SearchSysCacheExistsAttName(Oid relid, const char *attname);
extern HeapTuple SearchSysCacheAttNum(Oid relid, int16 attnum);
extern HeapTuple SearchSysCacheCopyAttNum(Oid relid, int16 attnum);
extern Datum SysCacheGetAttr(int cacheId, HeapTuple tup,
AttrNumber attributeNumber, bool *isNull);
extern Datum SysCacheGetAttrNotNull(int cacheId, HeapTuple tup,
AttrNumber attributeNumber);
extern uint32 GetSysCacheHashValue(int cacheId,
Datum key1, Datum key2, Datum key3, Datum key4);
/* list-search interface. Users of this must import catcache.h too */
struct catclist;
extern struct catclist *SearchSysCacheList(int cacheId, int nkeys,
Datum key1, Datum key2, Datum key3);
24 years ago
9 years ago
extern void SysCacheInvalidate(int cacheId, uint32 hashValue);
Use a safer method for determining whether relcache init file is stale. When we invalidate the relcache entry for a system catalog or index, we must also delete the relcache "init file" if the init file contains a copy of that rel's entry. The old way of doing this relied on a specially maintained list of the OIDs of relations present in the init file: we made the list either when reading the file in, or when writing the file out. The problem is that when writing the file out, we included only rels present in our local relcache, which might have already suffered some deletions due to relcache inval events. In such cases we correctly decided not to overwrite the real init file with incomplete data --- but we still used the incomplete initFileRelationIds list for the rest of the current session. This could result in wrong decisions about whether the session's own actions require deletion of the init file, potentially allowing an init file created by some other concurrent session to be left around even though it's been made stale. Since we don't support changing the schema of a system catalog at runtime, the only likely scenario in which this would cause a problem in the field involves a "vacuum full" on a catalog concurrently with other activity, and even then it's far from easy to provoke. Remarkably, this has been broken since 2002 (in commit 786340441706ac1957a031f11ad1c2e5b6e18314), but we had never seen a reproducible test case until recently. If it did happen in the field, the symptoms would probably involve unexpected "cache lookup failed" errors to begin with, then "could not open file" failures after the next checkpoint, as all accesses to the affected catalog stopped working. Recovery would require manually removing the stale "pg_internal.init" file. To fix, get rid of the initFileRelationIds list, and instead consult syscache.c's list of relations used in catalog caches to decide whether a relation is included in the init file. This should be a tad more efficient anyway, since we're replacing linear search of a list with ~100 entries with a binary search. It's a bit ugly that the init file contents are now so directly tied to the catalog caches, but in practice that won't make much difference. Back-patch to all supported branches.
11 years ago
extern bool RelationInvalidatesSnapshotsOnly(Oid relid);
extern bool RelationHasSysCache(Oid relid);
extern bool RelationSupportsSysCache(Oid relid);
/*
* The use of the macros below rather than direct calls to the corresponding
* functions is encouraged, as it insulates the caller from changes in the
* maximum number of keys.
*/
#define SearchSysCacheCopy1(cacheId, key1) \
SearchSysCacheCopy(cacheId, key1, 0, 0, 0)
#define SearchSysCacheCopy2(cacheId, key1, key2) \
SearchSysCacheCopy(cacheId, key1, key2, 0, 0)
#define SearchSysCacheCopy3(cacheId, key1, key2, key3) \
SearchSysCacheCopy(cacheId, key1, key2, key3, 0)
#define SearchSysCacheCopy4(cacheId, key1, key2, key3, key4) \
SearchSysCacheCopy(cacheId, key1, key2, key3, key4)
#define SearchSysCacheExists1(cacheId, key1) \
SearchSysCacheExists(cacheId, key1, 0, 0, 0)
#define SearchSysCacheExists2(cacheId, key1, key2) \
SearchSysCacheExists(cacheId, key1, key2, 0, 0)
#define SearchSysCacheExists3(cacheId, key1, key2, key3) \
SearchSysCacheExists(cacheId, key1, key2, key3, 0)
#define SearchSysCacheExists4(cacheId, key1, key2, key3, key4) \
SearchSysCacheExists(cacheId, key1, key2, key3, key4)
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
7 years ago
#define GetSysCacheOid1(cacheId, oidcol, key1) \
GetSysCacheOid(cacheId, oidcol, key1, 0, 0, 0)
#define GetSysCacheOid2(cacheId, oidcol, key1, key2) \
GetSysCacheOid(cacheId, oidcol, key1, key2, 0, 0)
#define GetSysCacheOid3(cacheId, oidcol, key1, key2, key3) \
GetSysCacheOid(cacheId, oidcol, key1, key2, key3, 0)
#define GetSysCacheOid4(cacheId, oidcol, key1, key2, key3, key4) \
GetSysCacheOid(cacheId, oidcol, key1, key2, key3, key4)
#define GetSysCacheHashValue1(cacheId, key1) \
GetSysCacheHashValue(cacheId, key1, 0, 0, 0)
#define GetSysCacheHashValue2(cacheId, key1, key2) \
GetSysCacheHashValue(cacheId, key1, key2, 0, 0)
#define GetSysCacheHashValue3(cacheId, key1, key2, key3) \
GetSysCacheHashValue(cacheId, key1, key2, key3, 0)
#define GetSysCacheHashValue4(cacheId, key1, key2, key3, key4) \
GetSysCacheHashValue(cacheId, key1, key2, key3, key4)
#define SearchSysCacheList1(cacheId, key1) \
SearchSysCacheList(cacheId, 1, key1, 0, 0)
#define SearchSysCacheList2(cacheId, key1, key2) \
SearchSysCacheList(cacheId, 2, key1, key2, 0)
#define SearchSysCacheList3(cacheId, key1, key2, key3) \
SearchSysCacheList(cacheId, 3, key1, key2, key3)
24 years ago
#define ReleaseSysCacheList(x) ReleaseCatCacheList(x)
Phase 2 of pgindent updates. Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
9 years ago
#endif /* SYSCACHE_H */