From 5ac54752a8c4f555b3ccc405c65e74614057bf34 Mon Sep 17 00:00:00 2001 From: Kyotaro Horiguchi Date: Fri, 10 Jan 2020 15:02:26 +0900 Subject: [PATCH v3 1/3] base_change Adds struct members needed by catcache expiration feature and a GUC variable that controls the behavior of the feature. But no substantial code is not added yet. If existence of some variables alone can cause degradation, benchmarking after this patch shows that. --- src/backend/access/transam/xact.c | 3 +++ src/backend/utils/cache/catcache.c | 15 +++++++++++++++ src/backend/utils/misc/guc.c | 13 +++++++++++++ src/include/utils/catcache.h | 20 ++++++++++++++++++++ 4 files changed, 51 insertions(+) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index af6afcebb1..1040713955 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1085,6 +1085,9 @@ ForceSyncCommit(void) static void AtStart_Cache(void) { + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); + AcceptInvalidationMessages(); } diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index 3613ae5f44..c5bad63aac 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -60,9 +60,18 @@ #define CACHE_elog(...) #endif +/* + * GUC variable to define the minimum age of entries that will be considered + * to be evicted in seconds. -1 to disable the feature. + */ +int catalog_cache_prune_min_age = 300; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +TimestampTz catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -99,6 +108,12 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); +/* GUC assign function */ +void +assign_catalog_cache_prune_min_age(int newval, void *extra) +{ + catalog_cache_prune_min_age = newval; +} /* * internal support functions diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index a62d64eaa4..628a95376c 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,8 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" +#include "utils/guc_tables.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -2358,6 +2360,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that live unused for longer than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + 300, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* * We use the hopefully-safely-small value of 100kB as the compiled-in * default for max_stack_depth. InitializeGUCOptions will increase it if diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index f4aa316604..3d3870f05a 100644 --- a/src/include/utils/catcache.h +++ b/src/include/utils/catcache.h @@ -22,6 +22,7 @@ #include "access/htup.h" #include "access/skey.h" +#include "datatype/timestamp.h" #include "lib/ilist.h" #include "utils/relcache.h" @@ -61,6 +62,7 @@ typedef struct catcache slist_node cc_next; /* list link */ ScanKeyData cc_skey[CATCACHE_MAXKEYS]; /* precomputed key info for heap * scans */ + TimestampTz cc_oldest_ts; /* timestamp of the oldest tuple in the hash */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,8 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + unsigned int naccess; /* # of access to this entry */ + TimestampTz lastaccess; /* timestamp of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +193,22 @@ typedef struct catcacheheader /* this extern duplicates utils/memutils.h... */ extern PGDLLIMPORT MemoryContext CacheMemoryContext; +/* for guc.c, not PGDLLPMPORT'ed */ +extern int catalog_cache_prune_min_age; + +/* source clock for access timestamp of catcache entries */ +extern TimestampTz catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clodk */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + + +extern void assign_catalog_cache_prune_min_age(int newval, void *extra); + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.18.4