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[PATCH v1 3/3] CatCache expiration feature. 77+ messages / 5 participants [nested] [flat]
* [PATCH v1 3/3] CatCache expiration feature. @ 2020-01-10 06:08 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-01-10 06:08 UTC (permalink / raw) This adds the catcache expiration feature to the catcache mechanism. Current catcache doesn't remove an entry and there's a case where many hash entries occupy large amont of memory , being not accessed ever after. This can be a quite serious issue on the cases of long-running sessions. The expiration feature keeps process memory usage below certain amount, in exchange of some extent of degradation if it is turned on. --- src/backend/utils/cache/catcache.c | 343 +++++++++++++++++++++++++++-- 1 file changed, 326 insertions(+), 17 deletions(-) diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index a4e3676a89..29bc980d8e 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -72,10 +72,11 @@ 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, - Datum v3, Datum v4); +/* basic catcache search functions */ +static inline HeapTuple SearchCatCacheInternalb(CatCache *cache, + int nkeys, + Datum v1, Datum v2, + Datum v3, Datum v4); static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, int nkeys, @@ -93,6 +94,23 @@ static HeapTuple SearchCatCache3b(CatCache *cache, static HeapTuple SearchCatCache4b(CatCache *cache, Datum v1, Datum v2, Datum v3, Datum v4); +/* catcache search functions with expiration feature */ +static inline HeapTuple SearchCatCacheInternale(CatCache *cache, + int nkeys, + Datum v1, Datum v2, + Datum v3, Datum v4); + +static HeapTuple SearchCatCachee(CatCache *cache, + Datum v1, Datum v2, Datum v3, Datum v4); +static HeapTuple SearchCatCache1e(CatCache *cache, Datum v1); +static HeapTuple SearchCatCache2e(CatCache *cache, Datum v1, Datum v2); +static HeapTuple SearchCatCache3e(CatCache *cache, + Datum v1, Datum v2, Datum v3); +static HeapTuple SearchCatCache4e(CatCache *cache, + Datum v1, Datum v2, Datum v3, Datum v4); + +static bool CatCacheCleanupOldEntries(CatCache *cp); + static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); static uint32 CatalogCacheComputeTupleHashValue(CatCache *cache, int nkeys, @@ -125,13 +143,35 @@ static SearchCatCacheFuncsType catcache_base = { SearchCatCache4b }; +static SearchCatCacheFuncsType catcache_expire = { + SearchCatCachee, + SearchCatCache1e, + SearchCatCache2e, + SearchCatCache3e, + SearchCatCache4e +}; + SearchCatCacheFuncsType *SearchCatCacheFuncs = NULL; +/* set catcache function set according to guc variables */ +static void +set_catcache_functions(void) +{ + if (catalog_cache_prune_min_age < 0) + SearchCatCacheFuncs = &catcache_base; + else + SearchCatCacheFuncs = &catcache_expire; +} + + /* GUC assign function */ void assign_catalog_cache_prune_min_age(int newval, void *extra) { catalog_cache_prune_min_age = newval; + + /* choose corresponding function set */ + set_catcache_functions(); } /* @@ -837,7 +877,7 @@ InitCatCache(int id, slist_init(&CacheHdr->ch_caches); CacheHdr->ch_ntup = 0; - SearchCatCacheFuncs = &catcache_base; + set_catcache_functions(); #ifdef CATCACHE_STATS /* set up to dump stats at backend exit */ @@ -900,6 +940,10 @@ RehashCatCache(CatCache *cp) int newnbuckets; int i; + /* try removing old entries before expanding hash */ + if (CatCacheCleanupOldEntries(cp)) + return; + elog(DEBUG1, "rehashing catalog cache id %d for %s; %d tups, %d buckets", cp->id, cp->cc_relname, cp->cc_ntup, cp->cc_nbuckets); @@ -1187,7 +1231,7 @@ SearchCatCacheb(CatCache *cache, Datum v3, Datum v4) { - return SearchCatCacheInternal(cache, cache->cc_nkeys, v1, v2, v3, v4); + return SearchCatCacheInternalb(cache, cache->cc_nkeys, v1, v2, v3, v4); } @@ -1201,7 +1245,7 @@ static HeapTuple SearchCatCache1b(CatCache *cache, Datum v1) { - return SearchCatCacheInternal(cache, 1, v1, 0, 0, 0); + return SearchCatCacheInternalb(cache, 1, v1, 0, 0, 0); } @@ -1209,7 +1253,7 @@ static HeapTuple SearchCatCache2b(CatCache *cache, Datum v1, Datum v2) { - return SearchCatCacheInternal(cache, 2, v1, v2, 0, 0); + return SearchCatCacheInternalb(cache, 2, v1, v2, 0, 0); } @@ -1217,7 +1261,7 @@ static HeapTuple SearchCatCache3b(CatCache *cache, Datum v1, Datum v2, Datum v3) { - return SearchCatCacheInternal(cache, 3, v1, v2, v3, 0); + return SearchCatCacheInternalb(cache, 3, v1, v2, v3, 0); } @@ -1225,19 +1269,19 @@ static HeapTuple SearchCatCache4b(CatCache *cache, Datum v1, Datum v2, Datum v3, Datum v4) { - return SearchCatCacheInternal(cache, 4, v1, v2, v3, v4); + return SearchCatCacheInternalb(cache, 4, v1, v2, v3, v4); } /* - * Work-horse for SearchCatCache/SearchCatCacheN. + * Work-horse for SearchCatCacheb/SearchCatCacheNb. */ static inline HeapTuple -SearchCatCacheInternal(CatCache *cache, - int nkeys, - Datum v1, - Datum v2, - Datum v3, - Datum v4) +SearchCatCacheInternalb(CatCache *cache, + int nkeys, + Datum v1, + Datum v2, + Datum v3, + Datum v4) { Datum arguments[CATCACHE_MAXKEYS]; uint32 hashValue; @@ -1462,6 +1506,269 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * SearchCatCache with entry pruning + * + * These functions works the same way with SearchCatCacheNb() functions except + * that less-used entries are removed following catalog_cache_prune_min_age + * setting. + */ +static HeapTuple +SearchCatCachee(CatCache *cache, + Datum v1, + Datum v2, + Datum v3, + Datum v4) +{ + return SearchCatCacheInternale(cache, cache->cc_nkeys, v1, v2, v3, v4); +} + + +/* + * SearchCatCacheN() are SearchCatCache() versions for a specific number of + * arguments. The compiler can inline the body and unroll loops, making them a + * bit faster than SearchCatCache(). + */ + +static HeapTuple +SearchCatCache1e(CatCache *cache, + Datum v1) +{ + return SearchCatCacheInternale(cache, 1, v1, 0, 0, 0); +} + + +static HeapTuple +SearchCatCache2e(CatCache *cache, + Datum v1, Datum v2) +{ + return SearchCatCacheInternale(cache, 2, v1, v2, 0, 0); +} + + +static HeapTuple +SearchCatCache3e(CatCache *cache, + Datum v1, Datum v2, Datum v3) +{ + return SearchCatCacheInternale(cache, 3, v1, v2, v3, 0); +} + + +static HeapTuple +SearchCatCache4e(CatCache *cache, + Datum v1, Datum v2, Datum v3, Datum v4) +{ + return SearchCatCacheInternale(cache, 4, v1, v2, v3, v4); +} + +/* + * Work-horse for SearchCatCachee/SearchCatCacheNe. + */ +static inline HeapTuple +SearchCatCacheInternale(CatCache *cache, + int nkeys, + Datum v1, + Datum v2, + Datum v3, + Datum v4) +{ + Datum arguments[CATCACHE_MAXKEYS]; + uint32 hashValue; + Index hashIndex; + dlist_iter iter; + dlist_head *bucket; + CatCTup *ct; + + /* Make sure we're in an xact, even if this ends up being a cache hit */ + Assert(IsTransactionState()); + + Assert(cache->cc_nkeys == nkeys); + + /* + * one-time startup overhead for each cache + */ + if (unlikely(cache->cc_tupdesc == NULL)) + CatalogCacheInitializeCache(cache); + +#ifdef CATCACHE_STATS + cache->cc_searches++; +#endif + + /* Initialize local parameter array */ + arguments[0] = v1; + arguments[1] = v2; + arguments[2] = v3; + arguments[3] = v4; + + /* + * find the hash bucket in which to look for the tuple + */ + hashValue = CatalogCacheComputeHashValue(cache, nkeys, v1, v2, v3, v4); + hashIndex = HASH_INDEX(hashValue, cache->cc_nbuckets); + + /* + * scan the hash bucket until we find a match or exhaust our tuples + * + * Note: it's okay to use dlist_foreach here, even though we modify the + * dlist within the loop, because we don't continue the loop afterwards. + */ + bucket = &cache->cc_bucket[hashIndex]; + dlist_foreach(iter, bucket) + { + ct = dlist_container(CatCTup, cache_elem, iter.cur); + + if (ct->dead) + continue; /* ignore dead entries */ + + if (ct->hash_value != hashValue) + continue; /* quickly skip entry if wrong hash val */ + + if (!CatalogCacheCompareTuple(cache, nkeys, ct->keys, arguments)) + continue; + + /* + * We found a match in the cache. Move it to the front of the list + * for its hashbucket, in order to speed subsequent searches. (The + * most frequently accessed elements in any hashbucket will tend to be + * near the front of the hashbucket's list.) + */ + dlist_move_head(bucket, &ct->cache_elem); + + /* + * Prolong life of this entry. Since we want run as less instructions + * as possible and want the branch be stable for performance reasons, + * we don't give a strict cap on the counter. All numbers above 1 will + * be regarded as 2 in CatCacheCleanupOldEntries(). + */ + ct->naccess++; + if (unlikely(ct->naccess == 0)) + ct->naccess = 2; + ct->lastaccess = catcacheclock; + + /* + * If it's a positive entry, bump its refcount and return it. If it's + * negative, we can report failure to the caller. + */ + if (!ct->negative) + { + ResourceOwnerEnlargeCatCacheRefs(CurrentResourceOwner); + ct->refcount++; + ResourceOwnerRememberCatCacheRef(CurrentResourceOwner, &ct->tuple); + + CACHE_elog(DEBUG2, "SearchCatCache(%s): found in bucket %d", + cache->cc_relname, hashIndex); + +#ifdef CATCACHE_STATS + cache->cc_hits++; +#endif + + return &ct->tuple; + } + else + { + CACHE_elog(DEBUG2, "SearchCatCache(%s): found neg entry in bucket %d", + cache->cc_relname, hashIndex); + +#ifdef CATCACHE_STATS + cache->cc_neg_hits++; +#endif + + return NULL; + } + } + + return SearchCatCacheMiss(cache, nkeys, hashValue, hashIndex, v1, v2, v3, v4); +} + +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + long age; + int us; + + /* Return immediately if disabled */ + if (catalog_cache_prune_min_age < 0) + return false; + + /* Don't scan the hash when we know we don't have prunable entries */ + TimestampDifference(cp->cc_oldest_ts, catcacheclock, &age, &us); + if (age < catalog_cache_prune_min_age) + return false; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + /* + * Calculate the duration from the time from the last access + * to the "current" time. catcacheclock is updated + * per-statement basis and additionaly udpated periodically + * during a long running query. + */ + TimestampDifference(ct->lastaccess, catcacheclock, &age, &us); + + if (age > catalog_cache_prune_min_age) + { + /* + * Entries that are not accessed after the last pruning + * are removed in that seconds, and their lives are + * prolonged according to how many times they are accessed + * up to three times of the duration. We don't try shrink + * buckets since pruning effectively caps catcache + * expansion in the long term. + */ + if (ct->naccess > 2) + ct->naccess = 1; + else if (ct->naccess > 0) + ct->naccess--; + else + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't update oldest_ts by removed entry */ + continue; + } + } + } + + /* update oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + + /* * ReleaseCatCache * @@ -1925,6 +2232,8 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->naccess = 0; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); -- 2.23.0 ----Next_Part(Wed_Jan_22_14_38_19_2020_534)-- Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="catcache-benchmark-extension.patch.txt" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH 4/4] CatCache expiration feature. @ 2020-01-10 06:08 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-01-10 06:08 UTC (permalink / raw) This adds the catcache expiration feature to the catcache mechanism. Current catcache doesn't remove a entry and there's a case where many hash entries occupy large amont of memory , being not accessed ever after. This is a quire serious issue on the cases of long-running sessions. The expiration feature saves the case in exchange of some extent of degradation if it is turned on. --- src/backend/utils/cache/catcache.c | 343 +++++++++++++++++++++++++++-- 1 file changed, 326 insertions(+), 17 deletions(-) diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index 74c893ba4e..35e1a07e57 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -72,10 +72,11 @@ 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, - Datum v3, Datum v4); +/* basic catcache search functions */ +static inline HeapTuple SearchCatCacheInternalb(CatCache *cache, + int nkeys, + Datum v1, Datum v2, + Datum v3, Datum v4); static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, int nkeys, @@ -93,6 +94,23 @@ static HeapTuple SearchCatCache3b(CatCache *cache, static HeapTuple SearchCatCache4b(CatCache *cache, Datum v1, Datum v2, Datum v3, Datum v4); +/* catcache search functions with expiration feature */ +static inline HeapTuple SearchCatCacheInternale(CatCache *cache, + int nkeys, + Datum v1, Datum v2, + Datum v3, Datum v4); + +static HeapTuple SearchCatCachee(CatCache *cache, + Datum v1, Datum v2, Datum v3, Datum v4); +static HeapTuple SearchCatCache1e(CatCache *cache, Datum v1); +static HeapTuple SearchCatCache2e(CatCache *cache, Datum v1, Datum v2); +static HeapTuple SearchCatCache3e(CatCache *cache, + Datum v1, Datum v2, Datum v3); +static HeapTuple SearchCatCache4e(CatCache *cache, + Datum v1, Datum v2, Datum v3, Datum v4); + +static bool CatCacheCleanupOldEntries(CatCache *cp); + static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); static uint32 CatalogCacheComputeTupleHashValue(CatCache *cache, int nkeys, @@ -125,13 +143,35 @@ static SearchCatCacheFuncsType catcache_base = { SearchCatCache4b }; +static SearchCatCacheFuncsType catcache_expire = { + SearchCatCachee, + SearchCatCache1e, + SearchCatCache2e, + SearchCatCache3e, + SearchCatCache4e +}; + SearchCatCacheFuncsType *SearchCatCacheFuncs = NULL; +/* set catcache function set according to guc variables */ +static void +set_catcache_functions(void) +{ + if (catalog_cache_prune_min_age < 0) + SearchCatCacheFuncs = &catcache_base; + else + SearchCatCacheFuncs = &catcache_expire; +} + + /* GUC assign function */ void assign_catalog_cache_prune_min_age(int newval, void *extra) { catalog_cache_prune_min_age = newval; + + /* choose corresponding function set */ + set_catcache_functions(); } /* @@ -872,7 +912,7 @@ InitCatCache(int id, slist_init(&CacheHdr->ch_caches); CacheHdr->ch_ntup = 0; - SearchCatCacheFuncs = &catcache_base; + set_catcache_functions(); #ifdef CATCACHE_STATS /* set up to dump stats at backend exit */ @@ -938,6 +978,10 @@ RehashCatCache(CatCache *cp) elog(DEBUG1, "rehashing catalog cache id %d for %s; %d tups, %d buckets", cp->id, cp->cc_relname, cp->cc_ntup, cp->cc_nbuckets); + /* try removing old entries before expanding hash */ + if (CatCacheCleanupOldEntries(cp)) + return; + /* Allocate a new, larger, hash table. */ newnbuckets = cp->cc_nbuckets * 2; newbucket = (dlist_head *) MemoryContextAllocZero(CacheMemoryContext, newnbuckets * sizeof(dlist_head)); @@ -1222,7 +1266,7 @@ SearchCatCacheb(CatCache *cache, Datum v3, Datum v4) { - return SearchCatCacheInternal(cache, cache->cc_nkeys, v1, v2, v3, v4); + return SearchCatCacheInternalb(cache, cache->cc_nkeys, v1, v2, v3, v4); } @@ -1236,7 +1280,7 @@ static HeapTuple SearchCatCache1b(CatCache *cache, Datum v1) { - return SearchCatCacheInternal(cache, 1, v1, 0, 0, 0); + return SearchCatCacheInternalb(cache, 1, v1, 0, 0, 0); } @@ -1244,7 +1288,7 @@ static HeapTuple SearchCatCache2b(CatCache *cache, Datum v1, Datum v2) { - return SearchCatCacheInternal(cache, 2, v1, v2, 0, 0); + return SearchCatCacheInternalb(cache, 2, v1, v2, 0, 0); } @@ -1252,7 +1296,7 @@ static HeapTuple SearchCatCache3b(CatCache *cache, Datum v1, Datum v2, Datum v3) { - return SearchCatCacheInternal(cache, 3, v1, v2, v3, 0); + return SearchCatCacheInternalb(cache, 3, v1, v2, v3, 0); } @@ -1260,19 +1304,19 @@ static HeapTuple SearchCatCache4b(CatCache *cache, Datum v1, Datum v2, Datum v3, Datum v4) { - return SearchCatCacheInternal(cache, 4, v1, v2, v3, v4); + return SearchCatCacheInternalb(cache, 4, v1, v2, v3, v4); } /* - * Work-horse for SearchCatCache/SearchCatCacheN. + * Work-horse for SearchCatCacheb/SearchCatCacheNb. */ static inline HeapTuple -SearchCatCacheInternal(CatCache *cache, - int nkeys, - Datum v1, - Datum v2, - Datum v3, - Datum v4) +SearchCatCacheInternalb(CatCache *cache, + int nkeys, + Datum v1, + Datum v2, + Datum v3, + Datum v4) { Datum arguments[CATCACHE_MAXKEYS]; uint32 hashValue; @@ -1497,6 +1541,269 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * SearchCatCache with entry pruning + * + * These functions works the same way with SearchCatCacheNb() functions except + * that less-used entries are removed following catalog_cache_prune_min_age + * setting. + */ +static HeapTuple +SearchCatCachee(CatCache *cache, + Datum v1, + Datum v2, + Datum v3, + Datum v4) +{ + return SearchCatCacheInternale(cache, cache->cc_nkeys, v1, v2, v3, v4); +} + + +/* + * SearchCatCacheN() are SearchCatCache() versions for a specific number of + * arguments. The compiler can inline the body and unroll loops, making them a + * bit faster than SearchCatCache(). + */ + +static HeapTuple +SearchCatCache1e(CatCache *cache, + Datum v1) +{ + return SearchCatCacheInternale(cache, 1, v1, 0, 0, 0); +} + + +static HeapTuple +SearchCatCache2e(CatCache *cache, + Datum v1, Datum v2) +{ + return SearchCatCacheInternale(cache, 2, v1, v2, 0, 0); +} + + +static HeapTuple +SearchCatCache3e(CatCache *cache, + Datum v1, Datum v2, Datum v3) +{ + return SearchCatCacheInternale(cache, 3, v1, v2, v3, 0); +} + + +static HeapTuple +SearchCatCache4e(CatCache *cache, + Datum v1, Datum v2, Datum v3, Datum v4) +{ + return SearchCatCacheInternale(cache, 4, v1, v2, v3, v4); +} + +/* + * Work-horse for SearchCatCachee/SearchCatCacheNe. + */ +static inline HeapTuple +SearchCatCacheInternale(CatCache *cache, + int nkeys, + Datum v1, + Datum v2, + Datum v3, + Datum v4) +{ + Datum arguments[CATCACHE_MAXKEYS]; + uint32 hashValue; + Index hashIndex; + dlist_iter iter; + dlist_head *bucket; + CatCTup *ct; + + /* Make sure we're in an xact, even if this ends up being a cache hit */ + Assert(IsTransactionState()); + + Assert(cache->cc_nkeys == nkeys); + + /* + * one-time startup overhead for each cache + */ + if (unlikely(cache->cc_tupdesc == NULL)) + CatalogCacheInitializeCache(cache); + +#ifdef CATCACHE_STATS + cache->cc_searches++; +#endif + + /* Initialize local parameter array */ + arguments[0] = v1; + arguments[1] = v2; + arguments[2] = v3; + arguments[3] = v4; + + /* + * find the hash bucket in which to look for the tuple + */ + hashValue = CatalogCacheComputeHashValue(cache, nkeys, v1, v2, v3, v4); + hashIndex = HASH_INDEX(hashValue, cache->cc_nbuckets); + + /* + * scan the hash bucket until we find a match or exhaust our tuples + * + * Note: it's okay to use dlist_foreach here, even though we modify the + * dlist within the loop, because we don't continue the loop afterwards. + */ + bucket = &cache->cc_bucket[hashIndex]; + dlist_foreach(iter, bucket) + { + ct = dlist_container(CatCTup, cache_elem, iter.cur); + + if (ct->dead) + continue; /* ignore dead entries */ + + if (ct->hash_value != hashValue) + continue; /* quickly skip entry if wrong hash val */ + + if (!CatalogCacheCompareTuple(cache, nkeys, ct->keys, arguments)) + continue; + + /* + * We found a match in the cache. Move it to the front of the list + * for its hashbucket, in order to speed subsequent searches. (The + * most frequently accessed elements in any hashbucket will tend to be + * near the front of the hashbucket's list.) + */ + dlist_move_head(bucket, &ct->cache_elem); + + /* + * Prolong life of this entry. Since we want run as less instructions + * as possible and want the branch be stable for performance reasons, + * we don't give a strict cap on the counter. All numbers above 1 will + * be regarded as 2 in CatCacheCleanupOldEntries(). + */ + ct->naccess++; + if (unlikely(ct->naccess == 0)) + ct->naccess = 2; + ct->lastaccess = catcacheclock; + + /* + * If it's a positive entry, bump its refcount and return it. If it's + * negative, we can report failure to the caller. + */ + if (!ct->negative) + { + ResourceOwnerEnlargeCatCacheRefs(CurrentResourceOwner); + ct->refcount++; + ResourceOwnerRememberCatCacheRef(CurrentResourceOwner, &ct->tuple); + + CACHE_elog(DEBUG2, "SearchCatCache(%s): found in bucket %d", + cache->cc_relname, hashIndex); + +#ifdef CATCACHE_STATS + cache->cc_hits++; +#endif + + return &ct->tuple; + } + else + { + CACHE_elog(DEBUG2, "SearchCatCache(%s): found neg entry in bucket %d", + cache->cc_relname, hashIndex); + +#ifdef CATCACHE_STATS + cache->cc_neg_hits++; +#endif + + return NULL; + } + } + + return SearchCatCacheMiss(cache, nkeys, hashValue, hashIndex, v1, v2, v3, v4); +} + +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + long age; + int us; + + /* Return immediately if disabled */ + if (catalog_cache_prune_min_age < 0) + return false; + + /* Don't scan the hash when we know we don't have prunable entries */ + TimestampDifference(cp->cc_oldest_ts, catcacheclock, &age, &us); + if (age < catalog_cache_prune_min_age) + return false; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + /* + * Calculate the duration from the time from the last access + * to the "current" time. catcacheclock is updated + * per-statement basis and additionaly udpated periodically + * during a long running query. + */ + TimestampDifference(ct->lastaccess, catcacheclock, &age, &us); + + if (age > catalog_cache_prune_min_age) + { + /* + * Entries that are not accessed after the last pruning + * are removed in that seconds, and their lives are + * prolonged according to how many times they are accessed + * up to three times of the duration. We don't try shrink + * buckets since pruning effectively caps catcache + * expansion in the long term. + */ + if (ct->naccess > 2) + ct->naccess = 1; + else if (ct->naccess > 0) + ct->naccess--; + else + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't update oldest_ts by removed entry */ + continue; + } + } + } + + /* update oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + + /* * ReleaseCatCache * @@ -1960,6 +2267,8 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->naccess = 0; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); -- 2.23.0 ----Next_Part(Tue_Jan_14_12_49_32_2020_834)-- Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="gen_tbl2.pl" #! /usr/bin/perl $collist = ""; foreach $i (0..1000) { $collist .= sprintf(", c%05d int", $i); } $collist = substr($collist, 2); printf "drop schema if exists test cascade;\n"; printf "create schema test;\n"; printf "create table test.p ($collist) partition by list (c00000);\n"; foreach $i (0..2999) { printf "create table test.t%04d partition of test.p for values in (%d);\n", $i, $i; } ----Next_Part(Tue_Jan_14_12_49_32_2020_834)-- Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="run4.sh" #!/bin/bash LOOPS=20 ITERATION=10 BINROOT=/home/horiguti/bin DATADIR=/home/horiguti/data/data_catexpe PREC="numeric(10,2)" /usr/bin/killall postgres /usr/bin/sleep 3 run() { local BINARY=$1 local PGCTL=$2/bin/pg_ctl local PGSQL=$2/bin/postgres local PSQL=$2/bin/psql if [ "$3" != "" ]; then local SETTING1="set catalog_cache_prune_min_age to \"$3\";" local SETTING2="set catalog_cache_prune_min_age to \"$4\";" local SETTING3="set catalog_cache_prune_min_age to \"$5\";" fi # ($PGSQL -D $DATADIR 2>&1 > /dev/null)& ($PGSQL -D $DATADIR 2>&1 > /dev/null | /usr/bin/sed -e 's/^/# /')& /usr/bin/sleep 3 ${PSQL} postgres <<EOF create extension if not exists catcachebench; select catcachebench(0); $SETTING3 select * from generate_series(2, 2) test, LATERAL (select '${BINARY}' as version, count(r)::text || '/${LOOPS}' as n, min(r)::${PREC}, stddev(r)::${PREC} from (select catcachebench(test) as r from generate_series(1, ${LOOPS})) r) r EOF $PGCTL --pgdata=$DATADIR stop 2>&1 > /dev/null | /usr/bin/sed -e 's/^/# /' # oreport > $BINARY_perf.txt } for i in $(seq 0 ${ITERATION}); do run "master" $BINROOT/pgsql_master_o2 "" "" "" run "base" $BINROOT/pgsql_catexp-base "" "" "" run "ind" $BINROOT/pgsql_catexp-ind "" "" "" run "expire-off" $BINROOT/pgsql_catexpe "-1" "-1" "-1" run "expire-on" $BINROOT/pgsql_catexpe "300s" "1s" "0" done ----Next_Part(Tue_Jan_14_12_49_32_2020_834)-- Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="build2.sh" #! /usr/bin/bash BINROOT=/home/horiguti/bin/pgsql_ for i in master_o2 catexp-base catexp-ind catexpe; do rm -r /home/horiguti/bin/pgsql_$i/*; done for i in master_o2 catexp-base catexp-ind catexpe; do ls -l /home/horiguti/bin/pgsql_$i/bin/postgres; done function build () { echo $1 make distclean git checkout $2 git diff master..HEAD > diff_$1.txt ./configure --enable-debug --enable-tap-tests --enable-nls --with-openssl --with-libxml --with-llvm --prefix=${BINROOT}$1 LLVM_CONFIG="/usr/bin/llvm-config" make -sj8 all make install cd contrib/catcachebench make clean make all make install cd ../.. } build "master_o2" "795e92756cd1" build "catexp-base" "b2ebc9b4f1c" build "catexp-ind" "631a04026d" build "catexpe" "025e5e8a98d" for i in master_o2 catexp-base catexp-ind catexpe; do ls -l /home/horiguti/bin/pgsql_$i/bin/postgres; done ----Next_Part(Tue_Jan_14_12_49_32_2020_834)---- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v2 3/3] CatCache expiration feature. @ 2020-01-10 06:08 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-01-10 06:08 UTC (permalink / raw) This adds the catcache expiration feature to the catcache mechanism. Current catcache doesn't remove an entry and there's a case where many hash entries occupy large amont of memory , being not accessed ever after. This can be a quite serious issue on the cases of long-running sessions. The expiration feature keeps process memory usage below certain amount, in exchange of some extent of degradation if it is turned on. --- src/backend/utils/cache/catcache.c | 344 +++++++++++++++++++++++++++-- 1 file changed, 327 insertions(+), 17 deletions(-) diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index e047389e16..be4c90af7d 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -72,10 +73,11 @@ 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, - Datum v3, Datum v4); +/* basic catcache search functions */ +static inline HeapTuple SearchCatCacheInternalb(CatCache *cache, + int nkeys, + Datum v1, Datum v2, + Datum v3, Datum v4); static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, int nkeys, @@ -93,6 +95,23 @@ static HeapTuple SearchCatCache3b(CatCache *cache, static HeapTuple SearchCatCache4b(CatCache *cache, Datum v1, Datum v2, Datum v3, Datum v4); +/* catcache search functions with expiration feature */ +static inline HeapTuple SearchCatCacheInternale(CatCache *cache, + int nkeys, + Datum v1, Datum v2, + Datum v3, Datum v4); + +static HeapTuple SearchCatCachee(CatCache *cache, + Datum v1, Datum v2, Datum v3, Datum v4); +static HeapTuple SearchCatCache1e(CatCache *cache, Datum v1); +static HeapTuple SearchCatCache2e(CatCache *cache, Datum v1, Datum v2); +static HeapTuple SearchCatCache3e(CatCache *cache, + Datum v1, Datum v2, Datum v3); +static HeapTuple SearchCatCache4e(CatCache *cache, + Datum v1, Datum v2, Datum v3, Datum v4); + +static bool CatCacheCleanupOldEntries(CatCache *cp); + static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); static uint32 CatalogCacheComputeTupleHashValue(CatCache *cache, int nkeys, @@ -125,13 +144,35 @@ static SearchCatCacheFuncsType catcache_base = { SearchCatCache4b }; +static SearchCatCacheFuncsType catcache_expire = { + SearchCatCachee, + SearchCatCache1e, + SearchCatCache2e, + SearchCatCache3e, + SearchCatCache4e +}; + SearchCatCacheFuncsType *SearchCatCacheFuncs = NULL; +/* set catcache function set according to guc variables */ +static void +set_catcache_functions(void) +{ + if (catalog_cache_prune_min_age < 0) + SearchCatCacheFuncs = &catcache_base; + else + SearchCatCacheFuncs = &catcache_expire; +} + + /* GUC assign function */ void assign_catalog_cache_prune_min_age(int newval, void *extra) { catalog_cache_prune_min_age = newval; + + /* choose corresponding function set */ + set_catcache_functions(); } /* @@ -837,7 +878,7 @@ InitCatCache(int id, slist_init(&CacheHdr->ch_caches); CacheHdr->ch_ntup = 0; - SearchCatCacheFuncs = &catcache_base; + set_catcache_functions(); #ifdef CATCACHE_STATS /* set up to dump stats at backend exit */ @@ -900,6 +941,10 @@ RehashCatCache(CatCache *cp) int newnbuckets; int i; + /* try removing old entries before expanding hash */ + if (CatCacheCleanupOldEntries(cp)) + return; + elog(DEBUG1, "rehashing catalog cache id %d for %s; %d tups, %d buckets", cp->id, cp->cc_relname, cp->cc_ntup, cp->cc_nbuckets); @@ -1187,7 +1232,7 @@ SearchCatCacheb(CatCache *cache, Datum v3, Datum v4) { - return SearchCatCacheInternal(cache, cache->cc_nkeys, v1, v2, v3, v4); + return SearchCatCacheInternalb(cache, cache->cc_nkeys, v1, v2, v3, v4); } @@ -1201,7 +1246,7 @@ static HeapTuple SearchCatCache1b(CatCache *cache, Datum v1) { - return SearchCatCacheInternal(cache, 1, v1, 0, 0, 0); + return SearchCatCacheInternalb(cache, 1, v1, 0, 0, 0); } @@ -1209,7 +1254,7 @@ static HeapTuple SearchCatCache2b(CatCache *cache, Datum v1, Datum v2) { - return SearchCatCacheInternal(cache, 2, v1, v2, 0, 0); + return SearchCatCacheInternalb(cache, 2, v1, v2, 0, 0); } @@ -1217,7 +1262,7 @@ static HeapTuple SearchCatCache3b(CatCache *cache, Datum v1, Datum v2, Datum v3) { - return SearchCatCacheInternal(cache, 3, v1, v2, v3, 0); + return SearchCatCacheInternalb(cache, 3, v1, v2, v3, 0); } @@ -1225,19 +1270,19 @@ static HeapTuple SearchCatCache4b(CatCache *cache, Datum v1, Datum v2, Datum v3, Datum v4) { - return SearchCatCacheInternal(cache, 4, v1, v2, v3, v4); + return SearchCatCacheInternalb(cache, 4, v1, v2, v3, v4); } /* - * Work-horse for SearchCatCache/SearchCatCacheN. + * Work-horse for SearchCatCacheb/SearchCatCacheNb. */ static inline HeapTuple -SearchCatCacheInternal(CatCache *cache, - int nkeys, - Datum v1, - Datum v2, - Datum v3, - Datum v4) +SearchCatCacheInternalb(CatCache *cache, + int nkeys, + Datum v1, + Datum v2, + Datum v3, + Datum v4) { Datum arguments[CATCACHE_MAXKEYS]; uint32 hashValue; @@ -1462,6 +1507,269 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * SearchCatCache with entry pruning + * + * These functions works the same way with SearchCatCacheNb() functions except + * that less-used entries are removed following catalog_cache_prune_min_age + * setting. + */ +static HeapTuple +SearchCatCachee(CatCache *cache, + Datum v1, + Datum v2, + Datum v3, + Datum v4) +{ + return SearchCatCacheInternale(cache, cache->cc_nkeys, v1, v2, v3, v4); +} + + +/* + * SearchCatCacheN() are SearchCatCache() versions for a specific number of + * arguments. The compiler can inline the body and unroll loops, making them a + * bit faster than SearchCatCache(). + */ + +static HeapTuple +SearchCatCache1e(CatCache *cache, + Datum v1) +{ + return SearchCatCacheInternale(cache, 1, v1, 0, 0, 0); +} + + +static HeapTuple +SearchCatCache2e(CatCache *cache, + Datum v1, Datum v2) +{ + return SearchCatCacheInternale(cache, 2, v1, v2, 0, 0); +} + + +static HeapTuple +SearchCatCache3e(CatCache *cache, + Datum v1, Datum v2, Datum v3) +{ + return SearchCatCacheInternale(cache, 3, v1, v2, v3, 0); +} + + +static HeapTuple +SearchCatCache4e(CatCache *cache, + Datum v1, Datum v2, Datum v3, Datum v4) +{ + return SearchCatCacheInternale(cache, 4, v1, v2, v3, v4); +} + +/* + * Work-horse for SearchCatCachee/SearchCatCacheNe. + */ +static inline HeapTuple +SearchCatCacheInternale(CatCache *cache, + int nkeys, + Datum v1, + Datum v2, + Datum v3, + Datum v4) +{ + Datum arguments[CATCACHE_MAXKEYS]; + uint32 hashValue; + Index hashIndex; + dlist_iter iter; + dlist_head *bucket; + CatCTup *ct; + + /* Make sure we're in an xact, even if this ends up being a cache hit */ + Assert(IsTransactionState()); + + Assert(cache->cc_nkeys == nkeys); + + /* + * one-time startup overhead for each cache + */ + if (unlikely(cache->cc_tupdesc == NULL)) + CatalogCacheInitializeCache(cache); + +#ifdef CATCACHE_STATS + cache->cc_searches++; +#endif + + /* Initialize local parameter array */ + arguments[0] = v1; + arguments[1] = v2; + arguments[2] = v3; + arguments[3] = v4; + + /* + * find the hash bucket in which to look for the tuple + */ + hashValue = CatalogCacheComputeHashValue(cache, nkeys, v1, v2, v3, v4); + hashIndex = HASH_INDEX(hashValue, cache->cc_nbuckets); + + /* + * scan the hash bucket until we find a match or exhaust our tuples + * + * Note: it's okay to use dlist_foreach here, even though we modify the + * dlist within the loop, because we don't continue the loop afterwards. + */ + bucket = &cache->cc_bucket[hashIndex]; + dlist_foreach(iter, bucket) + { + ct = dlist_container(CatCTup, cache_elem, iter.cur); + + if (ct->dead) + continue; /* ignore dead entries */ + + if (ct->hash_value != hashValue) + continue; /* quickly skip entry if wrong hash val */ + + if (!CatalogCacheCompareTuple(cache, nkeys, ct->keys, arguments)) + continue; + + /* + * We found a match in the cache. Move it to the front of the list + * for its hashbucket, in order to speed subsequent searches. (The + * most frequently accessed elements in any hashbucket will tend to be + * near the front of the hashbucket's list.) + */ + dlist_move_head(bucket, &ct->cache_elem); + + /* + * Prolong life of this entry. Since we want run as less instructions + * as possible and want the branch be stable for performance reasons, + * we don't give a strict cap on the counter. All numbers above 1 will + * be regarded as 2 in CatCacheCleanupOldEntries(). + */ + ct->naccess++; + if (unlikely(ct->naccess == 0)) + ct->naccess = 2; + ct->lastaccess = catcacheclock; + + /* + * If it's a positive entry, bump its refcount and return it. If it's + * negative, we can report failure to the caller. + */ + if (!ct->negative) + { + ResourceOwnerEnlargeCatCacheRefs(CurrentResourceOwner); + ct->refcount++; + ResourceOwnerRememberCatCacheRef(CurrentResourceOwner, &ct->tuple); + + CACHE_elog(DEBUG2, "SearchCatCache(%s): found in bucket %d", + cache->cc_relname, hashIndex); + +#ifdef CATCACHE_STATS + cache->cc_hits++; +#endif + + return &ct->tuple; + } + else + { + CACHE_elog(DEBUG2, "SearchCatCache(%s): found neg entry in bucket %d", + cache->cc_relname, hashIndex); + +#ifdef CATCACHE_STATS + cache->cc_neg_hits++; +#endif + + return NULL; + } + } + + return SearchCatCacheMiss(cache, nkeys, hashValue, hashIndex, v1, v2, v3, v4); +} + +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + long age; + int us; + + /* Return immediately if disabled */ + if (catalog_cache_prune_min_age < 0) + return false; + + /* Don't scan the hash when we know we don't have prunable entries */ + TimestampDifference(cp->cc_oldest_ts, catcacheclock, &age, &us); + if (age < catalog_cache_prune_min_age) + return false; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + /* + * Calculate the duration from the time from the last access + * to the "current" time. catcacheclock is updated + * per-statement basis and additionaly udpated periodically + * during a long running query. + */ + TimestampDifference(ct->lastaccess, catcacheclock, &age, &us); + + if (age > catalog_cache_prune_min_age) + { + /* + * Entries that are not accessed after the last pruning + * are removed in that seconds, and their lives are + * prolonged according to how many times they are accessed + * up to three times of the duration. We don't try shrink + * buckets since pruning effectively caps catcache + * expansion in the long term. + */ + if (ct->naccess > 2) + ct->naccess = 1; + else if (ct->naccess > 0) + ct->naccess--; + else + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't update oldest_ts by removed entry */ + continue; + } + } + } + + /* update oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + + /* * ReleaseCatCache * @@ -1925,6 +2233,8 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->naccess = 0; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); -- 2.18.4 ----Next_Part(Thu_Oct__1_16_47_18_2020_205)---- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v3 3/3] CatCache expiration feature. @ 2020-01-10 06:08 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-01-10 06:08 UTC (permalink / raw) This adds the catcache expiration feature to the catcache mechanism. Current catcache doesn't remove an entry and there's a case where many hash entries occupy large amont of memory , being not accessed ever after. This can be a quite serious issue on the cases of long-running sessions. The expiration feature keeps process memory usage below certain amount, in exchange of some extent of degradation if it is turned on. --- src/backend/utils/cache/catcache.c | 219 +++++++++++++++++++++++++++-- 1 file changed, 211 insertions(+), 8 deletions(-) diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index 7ac59bcdd6..a07b434fb6 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -72,7 +73,8 @@ static CatCacheHeader *CacheHdr = NULL; /* Clock for the last accessed time of a catcache entry. */ TimestampTz catcacheclock = 0; -static inline HeapTuple SearchCatCacheInternal(CatCache *cache, +static inline HeapTuple SearchCatCacheInternal(bool do_expire, + CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -93,6 +95,17 @@ static HeapTuple SearchCatCache3b(CatCache *cache, static HeapTuple SearchCatCache4b(CatCache *cache, Datum v1, Datum v2, Datum v3, Datum v4); +static HeapTuple SearchCatCachee(CatCache *cache, + Datum v1, Datum v2, Datum v3, Datum v4); +static HeapTuple SearchCatCache1e(CatCache *cache, Datum v1); +static HeapTuple SearchCatCache2e(CatCache *cache, Datum v1, Datum v2); +static HeapTuple SearchCatCache3e(CatCache *cache, + Datum v1, Datum v2, Datum v3); +static HeapTuple SearchCatCache4e(CatCache *cache, + Datum v1, Datum v2, Datum v3, Datum v4); + +static bool CatCacheCleanupOldEntries(CatCache *cp); + static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); static uint32 CatalogCacheComputeTupleHashValue(CatCache *cache, int nkeys, @@ -125,13 +138,35 @@ static SearchCatCacheFuncsType catcache_base = { SearchCatCache4b }; +static SearchCatCacheFuncsType catcache_expire = { + SearchCatCachee, + SearchCatCache1e, + SearchCatCache2e, + SearchCatCache3e, + SearchCatCache4e +}; + SearchCatCacheFuncsType *SearchCatCacheFuncs = NULL; +/* set catcache function set according to guc variables */ +static void +set_catcache_functions(void) +{ + if (catalog_cache_prune_min_age < 0) + SearchCatCacheFuncs = &catcache_base; + else + SearchCatCacheFuncs = &catcache_expire; +} + + /* GUC assign function */ void assign_catalog_cache_prune_min_age(int newval, void *extra) { catalog_cache_prune_min_age = newval; + + /* choose corresponding function set */ + set_catcache_functions(); } /* @@ -837,7 +872,7 @@ InitCatCache(int id, slist_init(&CacheHdr->ch_caches); CacheHdr->ch_ntup = 0; - SearchCatCacheFuncs = &catcache_base; + set_catcache_functions(); #ifdef CATCACHE_STATS /* set up to dump stats at backend exit */ @@ -900,6 +935,10 @@ RehashCatCache(CatCache *cp) int newnbuckets; int i; + /* try removing old entries before expanding hash */ + if (CatCacheCleanupOldEntries(cp)) + return; + elog(DEBUG1, "rehashing catalog cache id %d for %s; %d tups, %d buckets", cp->id, cp->cc_relname, cp->cc_ntup, cp->cc_nbuckets); @@ -1187,7 +1226,7 @@ SearchCatCacheb(CatCache *cache, Datum v3, Datum v4) { - return SearchCatCacheInternal(cache, cache->cc_nkeys, v1, v2, v3, v4); + return SearchCatCacheInternal(false, cache, cache->cc_nkeys, v1, v2, v3, v4); } @@ -1201,7 +1240,7 @@ static HeapTuple SearchCatCache1b(CatCache *cache, Datum v1) { - return SearchCatCacheInternal(cache, 1, v1, 0, 0, 0); + return SearchCatCacheInternal(false, cache, 1, v1, 0, 0, 0); } @@ -1209,7 +1248,7 @@ static HeapTuple SearchCatCache2b(CatCache *cache, Datum v1, Datum v2) { - return SearchCatCacheInternal(cache, 2, v1, v2, 0, 0); + return SearchCatCacheInternal(false, cache, 2, v1, v2, 0, 0); } @@ -1217,7 +1256,7 @@ static HeapTuple SearchCatCache3b(CatCache *cache, Datum v1, Datum v2, Datum v3) { - return SearchCatCacheInternal(cache, 3, v1, v2, v3, 0); + return SearchCatCacheInternal(false, cache, 3, v1, v2, v3, 0); } @@ -1225,14 +1264,18 @@ static HeapTuple SearchCatCache4b(CatCache *cache, Datum v1, Datum v2, Datum v3, Datum v4) { - return SearchCatCacheInternal(cache, 4, v1, v2, v3, v4); + return SearchCatCacheInternal(false, cache, 4, v1, v2, v3, v4); } /* * Work-horse for SearchCatCache/SearchCatCacheN. + * + * This function expects smarter compiler reduces useless paths by calling with + * fixed parameters. */ static inline HeapTuple -SearchCatCacheInternal(CatCache *cache, +SearchCatCacheInternal(bool do_expire, + CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -1301,6 +1344,20 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* + * Prolong life of this entry. Since we want run as less instructions + * as possible and want the branch be stable for performance reasons, + * we don't give a strict cap on the counter. All numbers above 1 will + * be regarded as 2 in CatCacheCleanupOldEntries(). + */ + if (do_expire) + { + ct->naccess++; + if (unlikely(ct->naccess == 0)) + ct->naccess = 2; + ct->lastaccess = catcacheclock; + } + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1462,6 +1519,150 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * SearchCatCache with entry pruning + * + * These functions works the same way with SearchCatCacheNb() functions except + * that less-used entries are removed following catalog_cache_prune_min_age + * setting. + */ +static HeapTuple +SearchCatCachee(CatCache *cache, + Datum v1, + Datum v2, + Datum v3, + Datum v4) +{ + return SearchCatCacheInternal(true, cache, cache->cc_nkeys, v1, v2, v3, v4); +} + + +/* + * SearchCatCacheN() are SearchCatCache() versions for a specific number of + * arguments. The compiler can inline the body and unroll loops, making them a + * bit faster than SearchCatCache(). + */ + +static HeapTuple +SearchCatCache1e(CatCache *cache, + Datum v1) +{ + return SearchCatCacheInternal(true, cache, 1, v1, 0, 0, 0); +} + + +static HeapTuple +SearchCatCache2e(CatCache *cache, + Datum v1, Datum v2) +{ + return SearchCatCacheInternal(true, cache, 2, v1, v2, 0, 0); +} + + +static HeapTuple +SearchCatCache3e(CatCache *cache, + Datum v1, Datum v2, Datum v3) +{ + return SearchCatCacheInternal(true, cache, 3, v1, v2, v3, 0); +} + + +static HeapTuple +SearchCatCache4e(CatCache *cache, + Datum v1, Datum v2, Datum v3, Datum v4) +{ + return SearchCatCacheInternal(true, cache, 4, v1, v2, v3, v4); +} + +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + long age; + int us; + + /* Return immediately if disabled */ + if (catalog_cache_prune_min_age < 0) + return false; + + /* Don't scan the hash when we know we don't have prunable entries */ + TimestampDifference(cp->cc_oldest_ts, catcacheclock, &age, &us); + if (age < catalog_cache_prune_min_age) + return false; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + /* + * Calculate the duration from the time from the last access + * to the "current" time. catcacheclock is updated + * per-statement basis and additionaly udpated periodically + * during a long running query. + */ + TimestampDifference(ct->lastaccess, catcacheclock, &age, &us); + + if (age > catalog_cache_prune_min_age) + { + /* + * Entries that are not accessed after the last pruning + * are removed in that seconds, and their lives are + * prolonged according to how many times they are accessed + * up to three times of the duration. We don't try shrink + * buckets since pruning effectively caps catcache + * expansion in the long term. + */ + if (ct->naccess > 2) + ct->naccess = 1; + else if (ct->naccess > 0) + ct->naccess--; + else + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't update oldest_ts by removed entry */ + continue; + } + } + } + + /* update oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + + /* * ReleaseCatCache * @@ -1925,6 +2126,8 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->naccess = 0; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); -- 2.18.4 ----Next_Part(Thu_Nov__5_16_26_55_2020_457)---- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v5] CatCache expiration feature @ 2020-11-06 08:27 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-06 08:27 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 + src/backend/utils/cache/catcache.c | 118 +++++++++++++++++++++++++++++ src/backend/utils/misc/guc.c | 12 +++ src/include/utils/catcache.h | 20 +++++ 4 files changed, 153 insertions(+) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index af6afcebb1..a246fcc4c0 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index 3613ae5f44..b457fed7ab 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +110,12 @@ 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 @@ -863,6 +880,10 @@ RehashCatCache(CatCache *cp) int newnbuckets; int i; + /* try removing old entries before expanding hash */ + if (CatCacheCleanupOldEntries(cp)) + return; + elog(DEBUG1, "rehashing catalog cache id %d for %s; %d tups, %d buckets", cp->id, cp->cc_relname, cp->cc_ntup, cp->cc_nbuckets); @@ -1264,6 +1285,16 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* + * Prolong life of this entry. Since we want run as less instructions + * as possible and want the branch be stable for performance reasons, + * we don't care of wrap-around and possible false-negative for old + * entries. The window is quite narrow and the counter doesn't gets so + * large while expiration is active. + */ + ct->naccess++; + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1456,91 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + long age; + int us; + + /* Return immediately if disabled */ + if (likely(catalog_cache_prune_min_age < 0)) + return false; + + /* Don't scan the hash when we know we don't have prunable entries */ + TimestampDifference(cp->cc_oldest_ts, catcacheclock, &age, &us); + if (age < catalog_cache_prune_min_age) + return false; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + /* + * Calculate the duration from the time from the last access + * to the "current" time. catcacheclock is updated + * per-statement basis and additionaly udpated periodically + * during a long running query. + */ + TimestampDifference(ct->lastaccess, catcacheclock, &age, &us); + + if (age > catalog_cache_prune_min_age) + { + /* + * Entries that are not accessed after the last pruning + * are removed in that seconds, and their lives are + * prolonged according to how many times they are accessed + * up to three times of the duration. We don't try shrink + * buckets since pruning effectively caps catcache + * expansion in the long term. + */ + ct->naccess = Min(2, ct->naccess); + if (--ct->naccess == 0) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't update oldest_ts by removed entry */ + continue; + } + } + } + + /* update oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +2004,8 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->naccess = 1; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index bb34630e8e..95213853aa 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3399,6 +3400,17 @@ static struct config_int ConfigureNamesInt[] = check_huge_page_size, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index f4aa316604..a11736f767 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 ----Next_Part(Mon_Nov__9_18_34_47_2020_166)---- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v4] CatCache expiration feature @ 2020-11-06 08:27 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-06 08:27 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 + src/backend/utils/cache/catcache.c | 125 +++++++++++++++++++++++++++++ src/backend/utils/misc/guc.c | 12 +++ src/include/utils/catcache.h | 20 +++++ 4 files changed, 160 insertions(+) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index af6afcebb1..a246fcc4c0 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index 3613ae5f44..f63224bfd5 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +110,12 @@ 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 @@ -863,6 +880,10 @@ RehashCatCache(CatCache *cp) int newnbuckets; int i; + /* try removing old entries before expanding hash */ + if (CatCacheCleanupOldEntries(cp)) + return; + elog(DEBUG1, "rehashing catalog cache id %d for %s; %d tups, %d buckets", cp->id, cp->cc_relname, cp->cc_ntup, cp->cc_nbuckets); @@ -1264,6 +1285,20 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* + * Prolong life of this entry. Since we want run as less instructions + * as possible and want the branch be stable for performance reasons, + * we don't give a strict cap on the counter. All numbers above 1 will + * be regarded as 2 in CatCacheCleanupOldEntries(). + */ + if (unlikely(catalog_cache_prune_min_age >= 0)) + { + ct->naccess++; + if (unlikely(ct->naccess == 0)) + ct->naccess = 2; + ct->lastaccess = catcacheclock; + } + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1460,94 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + long age; + int us; + + /* Return immediately if disabled */ + if (likely(catalog_cache_prune_min_age < 0)) + return false; + + /* Don't scan the hash when we know we don't have prunable entries */ + TimestampDifference(cp->cc_oldest_ts, catcacheclock, &age, &us); + if (age < catalog_cache_prune_min_age) + return false; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + /* + * Calculate the duration from the time from the last access + * to the "current" time. catcacheclock is updated + * per-statement basis and additionaly udpated periodically + * during a long running query. + */ + TimestampDifference(ct->lastaccess, catcacheclock, &age, &us); + + if (age > catalog_cache_prune_min_age) + { + /* + * Entries that are not accessed after the last pruning + * are removed in that seconds, and their lives are + * prolonged according to how many times they are accessed + * up to three times of the duration. We don't try shrink + * buckets since pruning effectively caps catcache + * expansion in the long term. + */ + if (ct->naccess > 2) + ct->naccess = 1; + else if (ct->naccess > 0) + ct->naccess--; + else + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't update oldest_ts by removed entry */ + continue; + } + } + } + + /* update oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +2011,8 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->naccess = 0; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index a62d64eaa4..ca897cab2e 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3399,6 +3400,17 @@ static struct config_int ConfigureNamesInt[] = check_huge_page_size, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index f4aa316604..a11736f767 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 ----Next_Part(Fri_Nov__6_17_29_58_2020_781)---- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v5 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index 03c553e7ea..4a2a90ce0c 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index 3613ae5f44..1ebcc7dcd3 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index bb34630e8e..95213853aa 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3399,6 +3400,17 @@ static struct config_int ConfigureNamesInt[] = check_huge_page_size, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index f4aa316604..81587c3fe6 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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 ----Next_Part(Thu_Nov_19_14_25_36_2020_063)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v5-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v6 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Thu_Jan_14_17_32_27_2021_995)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v7 1/3] CatCache expiration feature @ 2020-11-18 07:54 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Kyotaro Horiguchi @ 2020-11-18 07:54 UTC (permalink / raw) --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 87 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 19 +++++++ 4 files changed, 120 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..644d92dd9a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,19 @@ #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 = -1; +uint64 prune_min_age_us; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of a catcache entry. */ +uint64 catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +85,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,6 +111,15 @@ 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) +{ + if (newval < 0) + prune_min_age_us = UINT64_MAX; + else + prune_min_age_us = ((uint64) newval) * USECS_PER_SEC; +} /* * internal support functions @@ -1264,6 +1285,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1449,61 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + long oldest_ts = catcacheclock; + uint64 prune_threshold = catcacheclock - prune_min_age_us; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1967,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1979,12 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (catcacheclock - cache->cc_oldest_ts < prune_min_age_us || + !CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca..255e9fa73d 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, assign_catalog_cache_prune_min_age, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..291e857e38 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 */ + uint64 cc_oldest_ts; /* timestamp (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + uint64 lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,22 @@ 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 uint64 catcacheclock; + +/* SetCatCacheClock - set catcache timestamp source clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = (uint64) 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, -- 2.27.0 ----Next_Part(Wed_Jan_27_10_13_08_2021_482)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v7-0002-Remove-dead-flag-from-catcache-tuple.patch" ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v9] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- doc/src/sgml/config.sgml | 20 +++++++ src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 85 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 ++++++ 5 files changed, 136 insertions(+), 1 deletion(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index f1037df5a9..14be8061ce 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -1960,6 +1960,26 @@ include_dir 'conf.d' </listitem> </varlistentry> + <varlistentry id="guc-catalog-cache-prune-min-age" xreflabel="catalog_cache_prune_min_age"> + <term><varname>catalog_cache_prune_min_age</varname> (<type>integer</type>) + <indexterm> + <primary><varname>catalog_cache_prune_min_age</varname> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Setting <varname>catalog_cache_prune_min_age</varname> allows catalog + cache entries older than this seconds removed. A value + of <literal>-1</literal> disables this feature, effectively setting + the value to infinity. The default is 600 seconds. You can reduce + this value to reduce the amount of memory used by the catalog cache in + exchange of possible performance degradation or increase it to gain in + performance of intermittently executed queries in exchange of the + possible increase of memory usage. + </para> + </listitem> + </varlistentry> + </variablelist> </sect2> diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd4..86888d2409 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676..3e24a81992 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #define CACHE_elog(...) #endif +/* + * GUC variable to define the minimum age of entries that are the candidates + * for evictetion in seconds. -1 to disable the feature. + */ +int catalog_cache_prune_min_age = -1; + /* Cache management header --- pointer is NULL until created */ static CatCacheHeader *CacheHdr = NULL; +/* Clock for the last accessed time of catcache entry. */ +TimestampTz catcacheclock = 0; + static inline HeapTuple SearchCatCacheInternal(CatCache *cache, int nkeys, Datum v1, Datum v2, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -833,6 +844,7 @@ InitCatCache(int id, cp->cc_nkeys = nkeys; for (i = 0; i < nkeys; ++i) cp->cc_keyno[i] = key[i]; + cp->cc_oldest_ts = catcacheclock; /* * new cache is initialized as far as we can go for now. print some @@ -1264,6 +1276,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1440,69 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Removes entries that has been left alone for a certain period to prevent + * catcache bloat. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + /* entries older than this time would be removed */ + prune_threshold = catcacheclock - + ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* return if we know we have no entry to remove */ + if (cp->cc_oldest_ts > prune_threshold) + return false; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess <= prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1966,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1978,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index eafdb1118e..6a1e52911a 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are unused more than this seconds are to be removed."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + 600, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3..786df7aeda 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 */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp of the last use */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.27.0 ----Next_Part(Thu_Jan_28_16_50_44_2021_768)---- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* [PATCH v8 1/1] CatCache expiration feature @ 2021-01-27 11:08 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Heikki Linnakangas @ 2021-01-27 11:08 UTC (permalink / raw) Author: Kyotaro Horiguchi --- src/backend/access/transam/xact.c | 3 ++ src/backend/utils/cache/catcache.c | 82 +++++++++++++++++++++++++++++- src/backend/utils/misc/guc.c | 12 +++++ src/include/utils/catcache.h | 17 +++++++ 4 files changed, 112 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index a2068e3fd45..86888d24091 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -1086,6 +1086,9 @@ static void AtStart_Cache(void) { AcceptInvalidationMessages(); + + if (xactStartTimestamp != 0) + SetCatCacheClock(xactStartTimestamp); } /* diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c index fa2b49c676e..e29f825687a 100644 --- a/src/backend/utils/cache/catcache.c +++ b/src/backend/utils/cache/catcache.c @@ -38,6 +38,7 @@ #include "utils/rel.h" #include "utils/resowner_private.h" #include "utils/syscache.h" +#include "utils/timestamp.h" /* #define CACHEDEBUG */ /* turns DEBUG elogs on */ @@ -60,9 +61,18 @@ #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 = -1; + /* 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, @@ -74,6 +84,7 @@ static pg_noinline HeapTuple SearchCatCacheMiss(CatCache *cache, Index hashIndex, Datum v1, Datum v2, Datum v3, Datum v4); +static bool CatCacheCleanupOldEntries(CatCache *cp); static uint32 CatalogCacheComputeHashValue(CatCache *cache, int nkeys, Datum v1, Datum v2, Datum v3, Datum v4); @@ -99,7 +110,6 @@ static void CatCacheFreeKeys(TupleDesc tupdesc, int nkeys, int *attnos, static void CatCacheCopyKeys(TupleDesc tupdesc, int nkeys, int *attnos, Datum *srckeys, Datum *dstkeys); - /* * internal support functions */ @@ -1264,6 +1274,9 @@ SearchCatCacheInternal(CatCache *cache, */ dlist_move_head(bucket, &ct->cache_elem); + /* Record the last access timestamp */ + ct->lastaccess = catcacheclock; + /* * If it's a positive entry, bump its refcount and return it. If it's * negative, we can report failure to the caller. @@ -1425,6 +1438,66 @@ SearchCatCacheMiss(CatCache *cache, return &ct->tuple; } +/* + * CatCacheCleanupOldEntries - Remove infrequently-used entries + * + * Catcache entries happen to be left unused for a long time for several + * reasons. Remove such entries to prevent catcache from bloating. It is based + * on the similar algorithm with buffer eviction. Entries that are accessed + * several times in a certain period live longer than those that have had less + * access in the same duration. + */ +static bool +CatCacheCleanupOldEntries(CatCache *cp) +{ + int nremoved = 0; + int i; + TimestampTz oldest_ts = catcacheclock; + TimestampTz prune_threshold; + + if (catalog_cache_prune_min_age < 0) + return false; + + prune_threshold = catcacheclock - ((int64) catalog_cache_prune_min_age) * USECS_PER_SEC; + + /* Scan over the whole hash to find entries to remove */ + for (i = 0 ; i < cp->cc_nbuckets ; i++) + { + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &cp->cc_bucket[i]) + { + CatCTup *ct = dlist_container(CatCTup, cache_elem, iter.cur); + + /* Don't remove referenced entries */ + if (ct->refcount == 0 && + (ct->c_list == NULL || ct->c_list->refcount == 0)) + { + if (ct->lastaccess < prune_threshold) + { + CatCacheRemoveCTup(cp, ct); + nremoved++; + + /* don't let the removed entry update oldest_ts */ + continue; + } + } + + /* update the oldest timestamp if the entry remains alive */ + if (ct->lastaccess < oldest_ts) + oldest_ts = ct->lastaccess; + } + } + + cp->cc_oldest_ts = oldest_ts; + + if (nremoved > 0) + elog(DEBUG1, "pruning catalog cache id=%d for %s: removed %d / %d", + cp->id, cp->cc_relname, nremoved, cp->cc_ntup + nremoved); + + return nremoved > 0; +} + /* * ReleaseCatCache * @@ -1888,6 +1961,7 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, ct->dead = false; ct->negative = negative; ct->hash_value = hashValue; + ct->lastaccess = catcacheclock; dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem); @@ -1899,7 +1973,11 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp, Datum *arguments, * arbitrarily, we enlarge when fill factor > 2. */ if (cache->cc_ntup > cache->cc_nbuckets * 2) - RehashCatCache(cache); + { + /* try removing old entries before expanding hash */ + if (!CatCacheCleanupOldEntries(cache)) + RehashCatCache(cache); + } return ct; } diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 17579eeaca9..f92f0513a6f 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -88,6 +88,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/bytea.h" +#include "utils/catcache.h" #include "utils/float.h" #include "utils/guc_tables.h" #include "utils/memutils.h" @@ -3445,6 +3446,17 @@ static struct config_int ConfigureNamesInt[] = NULL, NULL, NULL }, + { + {"catalog_cache_prune_min_age", PGC_USERSET, RESOURCES_MEM, + gettext_noop("System catalog cache entries that are living unused more than this seconds are considered for removal."), + gettext_noop("The value of -1 turns off pruning."), + GUC_UNIT_S + }, + &catalog_cache_prune_min_age, + -1, -1, INT_MAX, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h index ddc2762eb3f..57a15bfec22 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 (us) of the oldest tuple */ /* * Keep these at the end, so that compiling catcache.c with CATCACHE_STATS @@ -119,6 +121,7 @@ typedef struct catctup bool dead; /* dead but not yet removed? */ bool negative; /* negative cache entry? */ HeapTupleData tuple; /* tuple management header */ + TimestampTz lastaccess; /* timestamp in us of the last usage */ /* * The tuple may also be a member of at most one CatCList. (If a single @@ -189,6 +192,20 @@ 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 clock */ +static inline void +SetCatCacheClock(TimestampTz ts) +{ + catcacheclock = ts; +} + extern void CreateCacheMemoryContext(void); extern CatCache *InitCatCache(int id, Oid reloid, Oid indexoid, -- 2.29.2 --------------38A9F5DCD32945DE1430BC1D-- ^ permalink raw reply [nested|flat] 77+ messages in thread
* Re: [PATCH] Fix old thinko in formula to compute sweight in numeric_sqrt(). @ 2023-01-29 13:33 Dean Rasheed <[email protected]> 0 siblings, 1 reply; 77+ messages in thread From: Dean Rasheed @ 2023-01-29 13:33 UTC (permalink / raw) To: Joel Jacobson <[email protected]>; +Cc: pgsql-hackers On Sat, 28 Jan 2023 at 22:14, Joel Jacobson <[email protected]> wrote: > > I found what appears to be a small harmless error in numeric.c, > that seems worthwhile to fix only because it's currently causes confusion. > Shrug. Looking at git blame, it's been like that for about 20 years, and I wasn't aware of it causing confusion. > HEAD, patched: > sweight = (arg.weight * DEC_DIGITS) / 2 + 1 > You haven't actually said why this formula is more correct than the current one. I believe that it is when arg.weight >= 0, but I'm not convinced it's correct for arg.weight < 0. Given that this is only an approximate computation, which ensures roughly 16 significant digits in the result, but can't guarantee exactly 16 digits, I'm not convinced of the benefits of changing it. > Note, however, that it's still possible to find examples of when sqrt(numeric) > produce results with different precision for different DEC_DIGITS/NBASE values, > but in such cases, it's intentional, and due to getting additional precision > for free, since the larger the NBASE, the more decimal digits are produced > at the same time per iteration in the calculation. > > Example: > > HEAD, unpatched > DEC_DIGITS sqrt(102::numeric) > 4 10.09950493836208 > 2 10.099504938362078 > 1 10.0995049383620780 > > HEAD, patched: > DEC_DIGITS sqrt(102::numeric) > 4 10.099504938362078 > 2 10.09950493836208 > 1 10.09950493836208 > > According to the comment in numeric_sqrt(), the goal is to give at least > NUMERIC_MIN_SIG_DIGITS (16) significant digits. > > Since 10.09950493836208 has 16 significant digits, we can see above how > DEC_DIGITS==2 causes an additional unnecessary significant digit to be computed, > and for DEC_DIGITS==1, two additional unnecessary significant digits are > computed. > > The patched version returns 16 significant digits as expected for DEC_DIGITS==2 > and DEC_DIGITS==1, and for DEC_DIGITS==4 we get an additional digit for free. > You lost me here. In unpatched HEAD, sqrt(102::numeric) produces 10.099504938362078, not 10.09950493836208 (with DEC_DIGITS = 4). And wasn't your previous point that when DEC_DIGITS = 4, the new formula is the same as the old one? > In conclusion, the proposed patch fixes a harmless problem, but is important > to fix, since otherwise, anyone who want to experiment with different > DEC_DIGITS/NBASE combinations by changing the `#if 0` preprocessor values > in the top of numeric.c will get surprising results from sqrt(). > Anyone changing DEC_DIGITS/NBASE will find hundreds of regression test failures due to changes in result precision all over the place (and failures due to the overflow limit changing). I don't see why numeric_sqrt() should be singled out for fixing. > In passing, also add pow10[] values for DEC_DIGITS==2 and DEC_DIGITS==1, > since otherwise it's not possible to compile such DEC_DIGITS values > due to the assert: > > StaticAssertDecl(lengthof(pow10) == DEC_DIGITS, "mismatch with DEC_DIGITS"); > That might be worth doing, to ensure that the code still compiles for other DEC_DIGITS/NBASE values. I'm not sure how useful that really is anymore though. As the comment at the top says, it's kept mostly for historical reasons. Regards, Dean ^ permalink raw reply [nested|flat] 77+ messages in thread
* Re: [PATCH] Fix old thinko in formula to compute sweight in numeric_sqrt(). @ 2023-01-31 07:59 Joel Jacobson <[email protected]> parent: Dean Rasheed <[email protected]> 0 siblings, 1 reply; 77+ messages in thread From: Joel Jacobson @ 2023-01-31 07:59 UTC (permalink / raw) To: Dean Rasheed <[email protected]>; +Cc: pgsql-hackers Hi, On Sun, Jan 29, 2023, at 14:33, Dean Rasheed wrote: > On Sat, 28 Jan 2023 at 22:14, Joel Jacobson <[email protected]> wrote: >> HEAD, patched: >> sweight = (arg.weight * DEC_DIGITS) / 2 + 1 > > You haven't actually said why this formula is more correct than the > current one. I believe that it is when arg.weight >= 0, but I'm not > convinced it's correct for arg.weight < 0. Ops, I totally failed to consider arg.weight < 0. Nice catch, thanks! It seems that, when arg.weight < 0, the current sweight formula in HEAD is correct, and, when arg.weight >= 0, the formula I suggested seems to be an improvement. I think this is what we want: if (arg.weight < 0) sweight = (arg.weight + 1) * DEC_DIGITS / 2 - 1; else sweight = arg.weight * DEC_DIGITS / 2 + 1; For DEC_DIGITS == 4, they are both the same, and become (arg.weight * 2 + 1). But when DEC_DIGITS != 4 && arg.weight >= 0, it's an improvement, as we then don't need to generate unnecessarily many sig. digits, and more often get exactly NUMERIC_MIN_SIG_DIGITS in the result, while still never getting fewer than NUMERIC_MIN_SIG_DIGITS. When DEC_DIGITS == 4, the compiler optimizes away the if/else, and compiles it to exactly the same code as the current sweight formula, tested with Godbolt: Test code: #define DEC_DIGITS 4 int sweight(weight) { if (weight < 0) return (weight + 1) * DEC_DIGITS / 2 - 1; else return weight * DEC_DIGITS / 2 + 1; } Output for x86-64 gcc (trunk): sweight: lea eax, [rdi+1+rdi] ret So, the extra if/else shouldn't cause any overhead, when DEC_DIGITS == 4. Not sure how/if it can be mathematically proven why it's more correct when DEC_DIGITS != 4, i.e., when it makes a difference. I derived it based on the insight that the square root weight should naturally be half the arg weight, and that the integer divison means we must adjust for when the weight is not evenly divisable by two. But it seems possible to gain some confidence about the correctness of the improvement by experimentally testing a wide range of negative/positive arg.weight. I wrote the attached script, test_sweight_formulas.sh, for that purpose. It compares the number of sig. digits in the result for sqrt(trim_scale(2::numeric*10::numeric^exp)) where exp is -40..40, that is, for args between 0.0000000000000000000000000000000000000002 0.000000000000000000000000000000000000002 ... 2000000000000000000000000000000000000000 20000000000000000000000000000000000000000 The last column shows the diff in number of sig. figs between HEAD and fix-sweight-v2. As expected, there is no difference for DEC_DIGITS == 4. But note the differences for DEC_DIGITS == 2 and DEC_DIGITS == 1 further down. -- -- Comparison of sig_figs(sqrt(n)) for HEAD vs fix-sweight-v2 -- when DEC_DIGITS == 4 -- DEC_DIGITS | n | HEAD | fix-sweight-v2 | diff ------------+--------------+------+----------------+------ 4 | 2e-40 | 21 | 21 | 0 4 | 2e-39 | 20 | 20 | 0 4 | 2e-38 | 20 | 20 | 0 4 | 2e-37 | 19 | 19 | 0 4 | 2e-36 | 19 | 19 | 0 4 | 2e-35 | 18 | 18 | 0 4 | 2e-34 | 18 | 18 | 0 4 | 2e-33 | 17 | 17 | 0 4 | 2e-32 | 17 | 17 | 0 4 | 2e-31 | 16 | 16 | 0 4 | 2e-30 | 17 | 17 | 0 4 | 2e-29 | 17 | 17 | 0 4 | 2e-28 | 16 | 16 | 0 4 | 2e-27 | 16 | 16 | 0 4 | 2e-26 | 17 | 17 | 0 4 | 2e-25 | 17 | 17 | 0 4 | 2e-24 | 16 | 16 | 0 4 | 2e-23 | 16 | 16 | 0 4 | 2e-22 | 17 | 17 | 0 4 | 2e-21 | 17 | 17 | 0 4 | 2e-20 | 16 | 16 | 0 4 | 2e-19 | 16 | 16 | 0 4 | 2e-18 | 17 | 17 | 0 4 | 2e-17 | 17 | 17 | 0 4 | 2e-16 | 16 | 16 | 0 4 | 2e-15 | 16 | 16 | 0 4 | 2e-14 | 17 | 17 | 0 4 | 2e-13 | 17 | 17 | 0 4 | 2e-12 | 16 | 16 | 0 4 | 2e-11 | 16 | 16 | 0 4 | 0.0000000002 | 17 | 17 | 0 4 | 0.000000002 | 17 | 17 | 0 4 | 0.00000002 | 16 | 16 | 0 4 | 0.0000002 | 16 | 16 | 0 4 | 0.000002 | 17 | 17 | 0 4 | 0.00002 | 17 | 17 | 0 4 | 0.0002 | 16 | 16 | 0 4 | 0.002 | 16 | 16 | 0 4 | 0.02 | 17 | 17 | 0 4 | 0.2 | 17 | 17 | 0 4 | 2 | 16 | 16 | 0 4 | 20 | 16 | 16 | 0 4 | 200 | 17 | 17 | 0 4 | 2000 | 17 | 17 | 0 4 | 20000 | 16 | 16 | 0 4 | 200000 | 16 | 16 | 0 4 | 2000000 | 17 | 17 | 0 4 | 20000000 | 17 | 17 | 0 4 | 200000000 | 16 | 16 | 0 4 | 2000000000 | 16 | 16 | 0 4 | 20000000000 | 17 | 17 | 0 4 | 2e+11 | 17 | 17 | 0 4 | 2e+12 | 16 | 16 | 0 4 | 2e+13 | 16 | 16 | 0 4 | 2e+14 | 17 | 17 | 0 4 | 2e+15 | 17 | 17 | 0 4 | 2e+16 | 16 | 16 | 0 4 | 2e+17 | 16 | 16 | 0 4 | 2e+18 | 17 | 17 | 0 4 | 2e+19 | 17 | 17 | 0 4 | 2e+20 | 16 | 16 | 0 4 | 2e+21 | 16 | 16 | 0 4 | 2e+22 | 17 | 17 | 0 4 | 2e+23 | 17 | 17 | 0 4 | 2e+24 | 16 | 16 | 0 4 | 2e+25 | 16 | 16 | 0 4 | 2e+26 | 17 | 17 | 0 4 | 2e+27 | 17 | 17 | 0 4 | 2e+28 | 16 | 16 | 0 4 | 2e+29 | 16 | 16 | 0 4 | 2e+30 | 17 | 17 | 0 4 | 2e+31 | 17 | 17 | 0 4 | 2e+32 | 17 | 17 | 0 4 | 2e+33 | 17 | 17 | 0 4 | 2e+34 | 18 | 18 | 0 4 | 2e+35 | 18 | 18 | 0 4 | 2e+36 | 19 | 19 | 0 4 | 2e+37 | 19 | 19 | 0 4 | 2e+38 | 20 | 20 | 0 4 | 2e+39 | 20 | 20 | 0 4 | 2e+40 | 21 | 21 | 0 (81 rows) -- -- Comparison of sig_figs(sqrt(n)) for HEAD vs fix-sweight-v2 -- when DEC_DIGITS == 2 -- DEC_DIGITS | n | HEAD | fix-sweight-v2 | diff ------------+--------------+------+----------------+------ 2 | 2e-40 | 21 | 21 | 0 2 | 2e-39 | 20 | 20 | 0 2 | 2e-38 | 20 | 20 | 0 2 | 2e-37 | 19 | 19 | 0 2 | 2e-36 | 19 | 19 | 0 2 | 2e-35 | 18 | 18 | 0 2 | 2e-34 | 18 | 18 | 0 2 | 2e-33 | 17 | 17 | 0 2 | 2e-32 | 17 | 17 | 0 2 | 2e-31 | 17 | 17 | 0 2 | 2e-30 | 17 | 17 | 0 2 | 2e-29 | 17 | 17 | 0 2 | 2e-28 | 17 | 17 | 0 2 | 2e-27 | 17 | 17 | 0 2 | 2e-26 | 17 | 17 | 0 2 | 2e-25 | 17 | 17 | 0 2 | 2e-24 | 17 | 17 | 0 2 | 2e-23 | 17 | 17 | 0 2 | 2e-22 | 17 | 17 | 0 2 | 2e-21 | 17 | 17 | 0 2 | 2e-20 | 17 | 17 | 0 2 | 2e-19 | 17 | 17 | 0 2 | 2e-18 | 17 | 17 | 0 2 | 2e-17 | 17 | 17 | 0 2 | 2e-16 | 17 | 17 | 0 2 | 2e-15 | 17 | 17 | 0 2 | 2e-14 | 17 | 17 | 0 2 | 2e-13 | 17 | 17 | 0 2 | 2e-12 | 17 | 17 | 0 2 | 2e-11 | 17 | 17 | 0 2 | 0.0000000002 | 17 | 17 | 0 2 | 0.000000002 | 17 | 17 | 0 2 | 0.00000002 | 17 | 17 | 0 2 | 0.0000002 | 17 | 17 | 0 2 | 0.000002 | 17 | 17 | 0 2 | 0.00002 | 17 | 17 | 0 2 | 0.0002 | 17 | 17 | 0 2 | 0.002 | 17 | 17 | 0 2 | 0.02 | 17 | 17 | 0 2 | 0.2 | 17 | 17 | 0 2 | 2 | 17 | 16 | -1 2 | 20 | 17 | 16 | -1 2 | 200 | 17 | 16 | -1 2 | 2000 | 17 | 16 | -1 2 | 20000 | 17 | 16 | -1 2 | 200000 | 17 | 16 | -1 2 | 2000000 | 17 | 16 | -1 2 | 20000000 | 17 | 16 | -1 2 | 200000000 | 17 | 16 | -1 2 | 2000000000 | 17 | 16 | -1 2 | 20000000000 | 17 | 16 | -1 2 | 2e+11 | 17 | 16 | -1 2 | 2e+12 | 17 | 16 | -1 2 | 2e+13 | 17 | 16 | -1 2 | 2e+14 | 17 | 16 | -1 2 | 2e+15 | 17 | 16 | -1 2 | 2e+16 | 17 | 16 | -1 2 | 2e+17 | 17 | 16 | -1 2 | 2e+18 | 17 | 16 | -1 2 | 2e+19 | 17 | 16 | -1 2 | 2e+20 | 17 | 16 | -1 2 | 2e+21 | 17 | 16 | -1 2 | 2e+22 | 17 | 16 | -1 2 | 2e+23 | 17 | 16 | -1 2 | 2e+24 | 17 | 16 | -1 2 | 2e+25 | 17 | 16 | -1 2 | 2e+26 | 17 | 16 | -1 2 | 2e+27 | 17 | 16 | -1 2 | 2e+28 | 17 | 16 | -1 2 | 2e+29 | 17 | 16 | -1 2 | 2e+30 | 17 | 16 | -1 2 | 2e+31 | 17 | 16 | -1 2 | 2e+32 | 17 | 17 | 0 2 | 2e+33 | 17 | 17 | 0 2 | 2e+34 | 18 | 18 | 0 2 | 2e+35 | 18 | 18 | 0 2 | 2e+36 | 19 | 19 | 0 2 | 2e+37 | 19 | 19 | 0 2 | 2e+38 | 20 | 20 | 0 2 | 2e+39 | 20 | 20 | 0 2 | 2e+40 | 21 | 21 | 0 (81 rows) -- -- Comparison of sig_figs(sqrt(n)) for HEAD vs fix-sweight-v2 -- when DEC_DIGITS == 1 -- DEC_DIGITS | n | HEAD | fix-sweight-v2 | diff ------------+--------------+------+----------------+------ 1 | 2e-40 | 21 | 21 | 0 1 | 2e-39 | 20 | 20 | 0 1 | 2e-38 | 20 | 20 | 0 1 | 2e-37 | 19 | 19 | 0 1 | 2e-36 | 19 | 19 | 0 1 | 2e-35 | 18 | 18 | 0 1 | 2e-34 | 18 | 18 | 0 1 | 2e-33 | 17 | 17 | 0 1 | 2e-32 | 17 | 17 | 0 1 | 2e-31 | 17 | 17 | 0 1 | 2e-30 | 17 | 17 | 0 1 | 2e-29 | 17 | 17 | 0 1 | 2e-28 | 17 | 17 | 0 1 | 2e-27 | 17 | 17 | 0 1 | 2e-26 | 17 | 17 | 0 1 | 2e-25 | 17 | 17 | 0 1 | 2e-24 | 17 | 17 | 0 1 | 2e-23 | 17 | 17 | 0 1 | 2e-22 | 17 | 17 | 0 1 | 2e-21 | 17 | 17 | 0 1 | 2e-20 | 17 | 17 | 0 1 | 2e-19 | 17 | 17 | 0 1 | 2e-18 | 17 | 17 | 0 1 | 2e-17 | 17 | 17 | 0 1 | 2e-16 | 17 | 17 | 0 1 | 2e-15 | 17 | 17 | 0 1 | 2e-14 | 17 | 17 | 0 1 | 2e-13 | 17 | 17 | 0 1 | 2e-12 | 17 | 17 | 0 1 | 2e-11 | 17 | 17 | 0 1 | 0.0000000002 | 17 | 17 | 0 1 | 0.000000002 | 17 | 17 | 0 1 | 0.00000002 | 17 | 17 | 0 1 | 0.0000002 | 17 | 17 | 0 1 | 0.000002 | 17 | 17 | 0 1 | 0.00002 | 17 | 17 | 0 1 | 0.0002 | 17 | 17 | 0 1 | 0.002 | 17 | 17 | 0 1 | 0.02 | 17 | 17 | 0 1 | 0.2 | 17 | 17 | 0 1 | 2 | 18 | 16 | -2 1 | 20 | 17 | 16 | -1 1 | 200 | 18 | 16 | -2 1 | 2000 | 17 | 16 | -1 1 | 20000 | 18 | 16 | -2 1 | 200000 | 17 | 16 | -1 1 | 2000000 | 18 | 16 | -2 1 | 20000000 | 17 | 16 | -1 1 | 200000000 | 18 | 16 | -2 1 | 2000000000 | 17 | 16 | -1 1 | 20000000000 | 18 | 16 | -2 1 | 2e+11 | 17 | 16 | -1 1 | 2e+12 | 18 | 16 | -2 1 | 2e+13 | 17 | 16 | -1 1 | 2e+14 | 18 | 16 | -2 1 | 2e+15 | 17 | 16 | -1 1 | 2e+16 | 18 | 16 | -2 1 | 2e+17 | 17 | 16 | -1 1 | 2e+18 | 18 | 16 | -2 1 | 2e+19 | 17 | 16 | -1 1 | 2e+20 | 18 | 16 | -2 1 | 2e+21 | 17 | 16 | -1 1 | 2e+22 | 18 | 16 | -2 1 | 2e+23 | 17 | 16 | -1 1 | 2e+24 | 18 | 16 | -2 1 | 2e+25 | 17 | 16 | -1 1 | 2e+26 | 18 | 16 | -2 1 | 2e+27 | 17 | 16 | -1 1 | 2e+28 | 18 | 16 | -2 1 | 2e+29 | 17 | 16 | -1 1 | 2e+30 | 18 | 16 | -2 1 | 2e+31 | 17 | 16 | -1 1 | 2e+32 | 18 | 17 | -1 1 | 2e+33 | 17 | 17 | 0 1 | 2e+34 | 18 | 18 | 0 1 | 2e+35 | 18 | 18 | 0 1 | 2e+36 | 19 | 19 | 0 1 | 2e+37 | 19 | 19 | 0 1 | 2e+38 | 20 | 20 | 0 1 | 2e+39 | 20 | 20 | 0 1 | 2e+40 | 21 | 21 | 0 (81 rows) > You lost me here. In unpatched HEAD, sqrt(102::numeric) produces > 10.099504938362078, not 10.09950493836208 (with DEC_DIGITS = 4). And > wasn't your previous point that when DEC_DIGITS = 4, the new formula > is the same as the old one? My apologies, I failed to correctly copy/paste the output from my terminal, into the right DEC_DIGITS example, which made it look like the output changed for DEC_DIGITS == 4 even though it didn't. Note to myself to always write a test script to ensure results are reproducible, which they now are thanks to the new test_sweight_formulas.sh script. >> In passing, also add pow10[] values for DEC_DIGITS==2 and DEC_DIGITS==1, >> since otherwise it's not possible to compile such DEC_DIGITS values >> due to the assert: >> >> StaticAssertDecl(lengthof(pow10) == DEC_DIGITS, "mismatch with DEC_DIGITS"); >> > > That might be worth doing, to ensure that the code still compiles for > other DEC_DIGITS/NBASE values. I'm not sure how useful that really is > anymore though. As the comment at the top says, it's kept mostly for > historical reasons. Attached patch fix-pow10-assert.patch /Joel Attachments: [application/octet-stream] fix-pow10-assert.patch (588B, ../../[email protected]/2-fix-pow10-assert.patch) download | inline diff: diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c index 898c52099b..834339dcff 100644 --- a/src/backend/utils/adt/numeric.c +++ b/src/backend/utils/adt/numeric.c @@ -4245,7 +4245,15 @@ int64_div_fast_to_numeric(int64 val1, int log10val2) */ if (m > 0) { +#if DEC_DIGITS == 4 static int pow10[] = {1, 10, 100, 1000}; +#elif DEC_DIGITS == 2 + static int pow10[] = {1, 10}; +#elif DEC_DIGITS == 1 + static int pow10[] = {1}; +#else +#error unsupported NBASE +#endif StaticAssertDecl(lengthof(pow10) == DEC_DIGITS, "mismatch with DEC_DIGITS"); [application/octet-stream] fix-sweight-v2.patch (596B, ../../[email protected]/3-fix-sweight-v2.patch) download | inline diff: diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c index 898c52099b..a42a6ceb18 100644 --- a/src/backend/utils/adt/numeric.c +++ b/src/backend/utils/adt/numeric.c @@ -3694,7 +3694,10 @@ numeric_sqrt(PG_FUNCTION_ARGS) init_var(&result); /* Assume the input was normalized, so arg.weight is accurate */ - sweight = (arg.weight + 1) * DEC_DIGITS / 2 - 1; + if (arg.weight < 0) + sweight = (arg.weight + 1) * DEC_DIGITS / 2 - 1; + else + sweight = arg.weight * DEC_DIGITS / 2 + 1; rscale = NUMERIC_MIN_SIG_DIGITS - sweight; rscale = Max(rscale, arg.dscale); [application/octet-stream] DEC_DIGITS_1.patch (566B, ../../[email protected]/4-DEC_DIGITS_1.patch) download | inline diff: diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c index 898c52099b..991315281a 100644 --- a/src/backend/utils/adt/numeric.c +++ b/src/backend/utils/adt/numeric.c @@ -72,7 +72,7 @@ * ---------- */ -#if 0 +#if 1 #define NBASE 10 #define HALF_NBASE 5 #define DEC_DIGITS 1 /* decimal digits per NBASE digit */ @@ -92,7 +92,7 @@ typedef signed char NumericDigit; typedef signed char NumericDigit; #endif -#if 1 +#if 0 #define NBASE 10000 #define HALF_NBASE 5000 #define DEC_DIGITS 4 /* decimal digits per NBASE digit */ [application/octet-stream] DEC_DIGITS_2.patch (591B, ../../[email protected]/5-DEC_DIGITS_2.patch) download | inline diff: diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c index 898c52099b..54f146f5fe 100644 --- a/src/backend/utils/adt/numeric.c +++ b/src/backend/utils/adt/numeric.c @@ -82,7 +82,7 @@ typedef signed char NumericDigit; #endif -#if 0 +#if 1 #define NBASE 100 #define HALF_NBASE 50 #define DEC_DIGITS 2 /* decimal digits per NBASE digit */ @@ -92,7 +92,7 @@ typedef signed char NumericDigit; typedef signed char NumericDigit; #endif -#if 1 +#if 0 #define NBASE 10000 #define HALF_NBASE 5000 #define DEC_DIGITS 4 /* decimal digits per NBASE digit */ [text/x-sh] test_sweight_formulas.sh (2.6K, ../../[email protected]/6-test_sweight_formulas.sh) download | inline: #!/bin/sh current_dir=$(pwd) export PGDATA="$current_dir/pgtemp-data" export PGPORT=54321 export PATH="$current_dir/pgtemp/bin:$PATH" if [ ! -d "postgresql" ]; then git clone https://git.postgresql.org/git/postgresql.git mv postgresql-foo postgresql ( cd postgresql && \ git reset --hard && \ ./configure --prefix="$current_dir/pgtemp" && \ make -j4 && \ make install ) && \ initdb && \ pg_ctl -l "$current_dir/pg.log" start && \ createdb "$USER" || \ exit 1 cat <<-"EOF" | psql -X || exit CREATE OR REPLACE FUNCTION sig_figs(numeric) RETURNS int LANGUAGE sql AS $$ SELECT 1+coalesce(floor(log(abs(nullif($1,0))))::int,0)+scale($1) $$; CREATE TABLE test_results ( "DEC_DIGITS" int, pg_version text, n_double double precision, -- used for sorting, can't use numeric since that's what we are testing n_text text, sqrt text, sqrt_text text, sqrt_sig_figs int ); EOF else pg_ctl -l "$current_dir/pg.log" start || exit cat <<-"EOF" | psql || exit TRUNCATE TABLE test_results; EOF fi for pg_version in "HEAD" "fix-sweight-v2"; do for DEC_DIGITS in 4 2 1; do ( cd postgresql && \ git reset --hard && \ git apply "$current_dir/fix-pow10-assert.patch" ) || exit if [ "$pg_version" != "HEAD" ] then (cd postgresql && \ git apply "$current_dir/$pg_version.patch") || exit fi if [ $DEC_DIGITS != 4 ] then (cd postgresql && \ git apply "$current_dir/DEC_DIGITS_$DEC_DIGITS.patch") || exit fi (cd postgresql && make install && pg_ctl restart) || exit cat <<-EOF | psql -X || exit WITH nums AS ( SELECT exp, trim_scale(2::numeric*10::numeric^exp) n FROM generate_series(-40,40) exp ) INSERT INTO test_results ("DEC_DIGITS", pg_version, n_double, n_text, sqrt, sqrt_sig_figs) SELECT '$DEC_DIGITS', '$pg_version', n::double precision, CASE WHEN abs(exp) > 10 THEN format('2e%s%s',CASE WHEN exp > 0 THEN '+' END,exp) ELSE n::text END, sqrt(n), sig_figs(sqrt(n)) FROM nums; EOF done done for DEC_DIGITS in 4 2 1; do echo "--" echo "-- Comparison of sig_figs(sqrt(n)) for HEAD vs fix-sweight-v2" echo "-- when DEC_DIGITS == $DEC_DIGITS" echo "--" cat <<-EOF | psql -X || exit SELECT a."DEC_DIGITS", a.n_text AS n, a.sqrt_sig_figs AS "HEAD", b.sqrt_sig_figs AS "fix-sweight-v2", b.sqrt_sig_figs - a.sqrt_sig_figs AS diff FROM test_results a JOIN test_results b USING ("DEC_DIGITS",n_text) WHERE a.pg_version = 'HEAD' AND b.pg_version = 'fix-sweight-v2' AND a."DEC_DIGITS" = $DEC_DIGITS ORDER BY a.n_double EOF done pg_ctl stop ^ permalink raw reply [nested|flat] 77+ messages in thread
* Re: [PATCH] Fix old thinko in formula to compute sweight in numeric_sqrt(). @ 2023-01-31 13:40 Dean Rasheed <[email protected]> parent: Joel Jacobson <[email protected]> 0 siblings, 1 reply; 77+ messages in thread From: Dean Rasheed @ 2023-01-31 13:40 UTC (permalink / raw) To: Joel Jacobson <[email protected]>; +Cc: pgsql-hackers On Tue, 31 Jan 2023 at 08:00, Joel Jacobson <[email protected]> wrote: > > I think this is what we want: > > if (arg.weight < 0) > sweight = (arg.weight + 1) * DEC_DIGITS / 2 - 1; > else > sweight = arg.weight * DEC_DIGITS / 2 + 1; > That's still not right. If you want a proper mathematically justified formula, it's fairly easy to derive. Let "n" be the decimal weight of the input, taken to be the number of decimal digits before the decimal point (or minus the number of zeros after the decimal point, for inputs with no digits before the decimal point). Similarly, let "sweight" be the decimal weight of the square root. Then the relationship between sweight and n can be seen from a few simple examples (to 4 significant digits): n arg sqrt(arg) sweight -3 0.0001 .. 0.0009999 0.01 .. 0.03162 -1 -2 0.001 .. 0.009999 0.03162 .. 0.09999 -1 -1 0.01 .. 0.09999 0.1 .. 0.3162 0 0 0.1 .. 0.9999 0.3162 .. 0.9999 0 1 1 .. 9.999 1 .. 3.162 1 2 10 .. 99.99 3.16 .. 9.999 1 3 100 .. 999.9 10 .. 31.62 2 4 1000 ... 9999 31.62 .. 99.99 2 and the general formula is: sweight = floor((n+1) / 2) In our case, since the base is NBASE, not 10, and since we only require an approximation, we don't take the trouble to compute n exactly, we just use the fact that it lies in the range arg.weight * DEC_DIGITS + 1 <= n <= (arg.weight + 1) * DEC_DIGITS Since we want to ensure at least a certain number of significant digits in the result, we're only interested in the lower bound. Plugging that into the formula above gives: sweight >= floor(arg.weight * DEC_DIGITS / 2 + 1) or equivalently, in code with truncated integer division: if (arg.weight >= 0) sweight = arg.weight * DEC_DIGITS / 2 + 1; else sweight = 1 - (1 - arg.weight * DEC_DIGITS) / 2; This is not the same as your formula. For example, when DEC_DIGITS = 1 and arg.weight = -1, yours gives sweight = -1 which isn't right, it should be 0. When DEC_DIGITS = 4, this formula also reduces to sweight = 2 * arg.weight + 1, but neither gcc nor clang is smart enough to spot that (clang doesn't simplify your formula either, BTW). So even though I believe that the above is mathematically correct, and won't change any results for DEC_DIGITS = 4, I'm still hesitant to use it, because it will have a (small) performance impact, and I don't believe it does anything to improve code readability (and certainly not without an explanatory comment). When DEC_DIGITS = 1, it does guarantee that the result has exactly 16 significant digits (or more if the input scale is larger), but that's only really of theoretical interest to anyone. As I noted above, when DEC_DIGITS > 1, this formula is only an approximation, since it's not using the exact input decimal weight. So my inclination is to leave the code as-is. It does guarantee that the result has at least 16 significant digits, which is the intention. Regards, Dean ^ permalink raw reply [nested|flat] 77+ messages in thread
* Re: [PATCH] Fix old thinko in formula to compute sweight in numeric_sqrt(). @ 2023-01-31 15:05 Joel Jacobson <[email protected]> parent: Dean Rasheed <[email protected]> 0 siblings, 1 reply; 77+ messages in thread From: Joel Jacobson @ 2023-01-31 15:05 UTC (permalink / raw) To: Dean Rasheed <[email protected]>; +Cc: pgsql-hackers Hi, On Tue, Jan 31, 2023, at 14:40, Dean Rasheed wrote: > That's still not right. If you want a proper mathematically justified > formula, it's fairly easy to derive. ... > or equivalently, in code with truncated integer division: > > if (arg.weight >= 0) > sweight = arg.weight * DEC_DIGITS / 2 + 1; > else > sweight = 1 - (1 - arg.weight * DEC_DIGITS) / 2; Beautiful! Thank you for magnificent analysis and extraordinary good explanation, now I finally get it. > When DEC_DIGITS = 4, this formula also reduces to sweight = 2 * > arg.weight + 1, but neither gcc nor clang is smart enough to spot that > (clang doesn't simplify your formula either, BTW). Oh, that's a shame. :-( > So even though I > believe that the above is mathematically correct, and won't change any > results for DEC_DIGITS = 4, I'm still hesitant to use it, because it > will have a (small) performance impact, and I don't believe it does > anything to improve code readability (and certainly not without an > explanatory comment). I also think the performance impact no matter how small isn't worth it, but a comment based on your comments would be very valuable IMO. Below is an attempt at summarising your text, and to avoid the performance impact, maybe an #if so we get the general correct formula for DEC_DIGITS 1 or 2, and the reduced hand-optimised form for DEC_DIGITS 4? That could also improve readabilty, since readers perhaps more easily would see the relation between sweight and arg.weight, for the only DEC_DIGITS case we care about. Suggestion: /* * Here we approximate the decimal weight of the square root (sweight), * given the NBASE-weight (arg.weight) of the input argument. * * The lower bound of the decimal weight of the input argument is used to * calculate the decimal weight of the square root, with integer division * being truncated. * * The general formula is: * * sweight = floor((n+1) / 2) * * In our case, since the base is NBASE, not 10, and since we only * require an approximation, we don't take the trouble to compute n * exactly, we just use the fact that it lies in the range * * arg.weight * DEC_DIGITS + 1 <= n <= (arg.weight + 1) * DEC_DIGITS * * Since we want to ensure at least a certain number of significant * digits in the result, we're only interested in the lower bound. * Plugging that into the formula above gives: * * sweight >= floor(arg.weight * DEC_DIGITS / 2 + 1) * * Which leads us to the formula below with truncated integer division. */ #if DEC_DIGITS == 1 || DEC_DIGITS == 2 if (arg.weight >= 0) sweight = arg.weight * DEC_DIGITS / 2 + 1; else sweight = 1 - (1 - arg.weight * DEC_DIGITS) / 2; #elif DEC_DIGITS == 4 /* * Neither gcc nor clang is smart enough to spot that * the formula above neatly reduces to the below * when DEC_DIGITS == 4. */ sweight = 2 * arg.weight + 1; #else #error unsupported NBASE #endif /Joel ^ permalink raw reply [nested|flat] 77+ messages in thread
* Re: [PATCH] Fix old thinko in formula to compute sweight in numeric_sqrt(). @ 2023-01-31 19:25 Dean Rasheed <[email protected]> parent: Joel Jacobson <[email protected]> 0 siblings, 1 reply; 77+ messages in thread From: Dean Rasheed @ 2023-01-31 19:25 UTC (permalink / raw) To: Joel Jacobson <[email protected]>; +Cc: pgsql-hackers On Tue, 31 Jan 2023 at 15:05, Joel Jacobson <[email protected]> wrote: > > I also think the performance impact no matter how small isn't worth it, > but a comment based on your comments would be very valuable IMO. > > Below is an attempt at summarising your text, and to avoid the performance impact, > maybe an #if so we get the general correct formula for DEC_DIGITS 1 or 2, > and the reduced hand-optimised form for DEC_DIGITS 4? > That could also improve readabilty, since readers perhaps more easily would see > the relation between sweight and arg.weight, for the only DEC_DIGITS case we care about. > That seems a bit wordy, given the context of this comment. I think it's sufficient to just give the formula, and note that it simplifies when DEC_DIGITS is even (not just 4): /* * Assume the input was normalized, so arg.weight is accurate. The result * then has at least sweight = floor(arg.weight * DEC_DIGITS / 2 + 1) * digits before the decimal point. When DEC_DIGITS is even, we can save * a few cycles, since the division is exact and there is no need to * round down. */ #if DEC_DIGITS == ((DEC_DIGITS / 2) * 2) sweight = arg.weight * DEC_DIGITS / 2 + 1; #else if (arg.weight >= 0) sweight = arg.weight * DEC_DIGITS / 2 + 1; else sweight = 1 - (1 - arg.weight * DEC_DIGITS) / 2; #endif Regards, Dean ^ permalink raw reply [nested|flat] 77+ messages in thread
* Re: [PATCH] Fix old thinko in formula to compute sweight in numeric_sqrt(). @ 2023-01-31 21:59 Joel Jacobson <[email protected]> parent: Dean Rasheed <[email protected]> 0 siblings, 0 replies; 77+ messages in thread From: Joel Jacobson @ 2023-01-31 21:59 UTC (permalink / raw) To: Dean Rasheed <[email protected]>; +Cc: pgsql-hackers On Tue, Jan 31, 2023, at 20:25, Dean Rasheed wrote: > That seems a bit wordy, given the context of this comment. I think > it's sufficient to just give the formula, and note that it simplifies > when DEC_DIGITS is even (not just 4): > > /* > * Assume the input was normalized, so arg.weight is accurate. The result > * then has at least sweight = floor(arg.weight * DEC_DIGITS / 2 + 1) > * digits before the decimal point. When DEC_DIGITS is even, we can save > * a few cycles, since the division is exact and there is no need to > * round down. > */ > #if DEC_DIGITS == ((DEC_DIGITS / 2) * 2) > sweight = arg.weight * DEC_DIGITS / 2 + 1; > #else > if (arg.weight >= 0) > sweight = arg.weight * DEC_DIGITS / 2 + 1; > else > sweight = 1 - (1 - arg.weight * DEC_DIGITS) / 2; > #endif Nice, you managed to simplify it even further. I think the comment and the code now are crystal clear together. I've tested it successfully, test report attached. In summary: DEC_DIGITS=1 now produce 16 sig. figs. in the range sqrt(2e-31) .. sqrt(2e+32), which before had a mix of 17 and 18 sig. figs in the result. DEC_DIGTIS=2 now produce 16 sig. figs. in the range sqrt(2e-31) .. sqrt(2e+31), which before always had 17 sig. figs in the result. DEC_DIGITS=4 is unchanged. Exact tested patch attached, code copy/pasted verbatim from your email. Test -- -- Comparison of sig_figs(sqrt(n)) for HEAD vs fix-sweight-v4 -- when DEC_DIGITS == 1 -- DEC_DIGITS | n | HEAD | fix-sweight-v4 | diff ------------+--------------+------+----------------+------ 1 | 2e-100 | 51 | 51 | 0 1 | 2e-99 | 50 | 50 | 0 1 | 2e-98 | 50 | 50 | 0 1 | 2e-97 | 49 | 49 | 0 1 | 2e-96 | 49 | 49 | 0 1 | 2e-95 | 48 | 48 | 0 1 | 2e-94 | 48 | 48 | 0 1 | 2e-93 | 47 | 47 | 0 1 | 2e-92 | 47 | 47 | 0 1 | 2e-91 | 46 | 46 | 0 1 | 2e-90 | 46 | 46 | 0 1 | 2e-89 | 45 | 45 | 0 1 | 2e-88 | 45 | 45 | 0 1 | 2e-87 | 44 | 44 | 0 1 | 2e-86 | 44 | 44 | 0 1 | 2e-85 | 43 | 43 | 0 1 | 2e-84 | 43 | 43 | 0 1 | 2e-83 | 42 | 42 | 0 1 | 2e-82 | 42 | 42 | 0 1 | 2e-81 | 41 | 41 | 0 1 | 2e-80 | 41 | 41 | 0 1 | 2e-79 | 40 | 40 | 0 1 | 2e-78 | 40 | 40 | 0 1 | 2e-77 | 39 | 39 | 0 1 | 2e-76 | 39 | 39 | 0 1 | 2e-75 | 38 | 38 | 0 1 | 2e-74 | 38 | 38 | 0 1 | 2e-73 | 37 | 37 | 0 1 | 2e-72 | 37 | 37 | 0 1 | 2e-71 | 36 | 36 | 0 1 | 2e-70 | 36 | 36 | 0 1 | 2e-69 | 35 | 35 | 0 1 | 2e-68 | 35 | 35 | 0 1 | 2e-67 | 34 | 34 | 0 1 | 2e-66 | 34 | 34 | 0 1 | 2e-65 | 33 | 33 | 0 1 | 2e-64 | 33 | 33 | 0 1 | 2e-63 | 32 | 32 | 0 1 | 2e-62 | 32 | 32 | 0 1 | 2e-61 | 31 | 31 | 0 1 | 2e-60 | 31 | 31 | 0 1 | 2e-59 | 30 | 30 | 0 1 | 2e-58 | 30 | 30 | 0 1 | 2e-57 | 29 | 29 | 0 1 | 2e-56 | 29 | 29 | 0 1 | 2e-55 | 28 | 28 | 0 1 | 2e-54 | 28 | 28 | 0 1 | 2e-53 | 27 | 27 | 0 1 | 2e-52 | 27 | 27 | 0 1 | 2e-51 | 26 | 26 | 0 1 | 2e-50 | 26 | 26 | 0 1 | 2e-49 | 25 | 25 | 0 1 | 2e-48 | 25 | 25 | 0 1 | 2e-47 | 24 | 24 | 0 1 | 2e-46 | 24 | 24 | 0 1 | 2e-45 | 23 | 23 | 0 1 | 2e-44 | 23 | 23 | 0 1 | 2e-43 | 22 | 22 | 0 1 | 2e-42 | 22 | 22 | 0 1 | 2e-41 | 21 | 21 | 0 1 | 2e-40 | 21 | 21 | 0 1 | 2e-39 | 20 | 20 | 0 1 | 2e-38 | 20 | 20 | 0 1 | 2e-37 | 19 | 19 | 0 1 | 2e-36 | 19 | 19 | 0 1 | 2e-35 | 18 | 18 | 0 1 | 2e-34 | 18 | 18 | 0 1 | 2e-33 | 17 | 17 | 0 1 | 2e-32 | 17 | 17 | 0 1 | 2e-31 | 17 | 16 | -1 1 | 2e-30 | 17 | 16 | -1 1 | 2e-29 | 17 | 16 | -1 1 | 2e-28 | 17 | 16 | -1 1 | 2e-27 | 17 | 16 | -1 1 | 2e-26 | 17 | 16 | -1 1 | 2e-25 | 17 | 16 | -1 1 | 2e-24 | 17 | 16 | -1 1 | 2e-23 | 17 | 16 | -1 1 | 2e-22 | 17 | 16 | -1 1 | 2e-21 | 17 | 16 | -1 1 | 2e-20 | 17 | 16 | -1 1 | 2e-19 | 17 | 16 | -1 1 | 2e-18 | 17 | 16 | -1 1 | 2e-17 | 17 | 16 | -1 1 | 2e-16 | 17 | 16 | -1 1 | 2e-15 | 17 | 16 | -1 1 | 2e-14 | 17 | 16 | -1 1 | 2e-13 | 17 | 16 | -1 1 | 2e-12 | 17 | 16 | -1 1 | 2e-11 | 17 | 16 | -1 1 | 0.0000000002 | 17 | 16 | -1 1 | 0.000000002 | 17 | 16 | -1 1 | 0.00000002 | 17 | 16 | -1 1 | 0.0000002 | 17 | 16 | -1 1 | 0.000002 | 17 | 16 | -1 1 | 0.00002 | 17 | 16 | -1 1 | 0.0002 | 17 | 16 | -1 1 | 0.002 | 17 | 16 | -1 1 | 0.02 | 17 | 16 | -1 1 | 0.2 | 17 | 16 | -1 1 | 2 | 18 | 16 | -2 1 | 20 | 17 | 16 | -1 1 | 200 | 18 | 16 | -2 1 | 2000 | 17 | 16 | -1 1 | 20000 | 18 | 16 | -2 1 | 200000 | 17 | 16 | -1 1 | 2000000 | 18 | 16 | -2 1 | 20000000 | 17 | 16 | -1 1 | 200000000 | 18 | 16 | -2 1 | 2000000000 | 17 | 16 | -1 1 | 20000000000 | 18 | 16 | -2 1 | 2e+11 | 17 | 16 | -1 1 | 2e+12 | 18 | 16 | -2 1 | 2e+13 | 17 | 16 | -1 1 | 2e+14 | 18 | 16 | -2 1 | 2e+15 | 17 | 16 | -1 1 | 2e+16 | 18 | 16 | -2 1 | 2e+17 | 17 | 16 | -1 1 | 2e+18 | 18 | 16 | -2 1 | 2e+19 | 17 | 16 | -1 1 | 2e+20 | 18 | 16 | -2 1 | 2e+21 | 17 | 16 | -1 1 | 2e+22 | 18 | 16 | -2 1 | 2e+23 | 17 | 16 | -1 1 | 2e+24 | 18 | 16 | -2 1 | 2e+25 | 17 | 16 | -1 1 | 2e+26 | 18 | 16 | -2 1 | 2e+27 | 17 | 16 | -1 1 | 2e+28 | 18 | 16 | -2 1 | 2e+29 | 17 | 16 | -1 1 | 2e+30 | 18 | 16 | -2 1 | 2e+31 | 17 | 16 | -1 1 | 2e+32 | 18 | 17 | -1 1 | 2e+33 | 17 | 17 | 0 1 | 2e+34 | 18 | 18 | 0 1 | 2e+35 | 18 | 18 | 0 1 | 2e+36 | 19 | 19 | 0 1 | 2e+37 | 19 | 19 | 0 1 | 2e+38 | 20 | 20 | 0 1 | 2e+39 | 20 | 20 | 0 1 | 2e+40 | 21 | 21 | 0 1 | 2e+41 | 21 | 21 | 0 1 | 2e+42 | 22 | 22 | 0 1 | 2e+43 | 22 | 22 | 0 1 | 2e+44 | 23 | 23 | 0 1 | 2e+45 | 23 | 23 | 0 1 | 2e+46 | 24 | 24 | 0 1 | 2e+47 | 24 | 24 | 0 1 | 2e+48 | 25 | 25 | 0 1 | 2e+49 | 25 | 25 | 0 1 | 2e+50 | 26 | 26 | 0 1 | 2e+51 | 26 | 26 | 0 1 | 2e+52 | 27 | 27 | 0 1 | 2e+53 | 27 | 27 | 0 1 | 2e+54 | 28 | 28 | 0 1 | 2e+55 | 28 | 28 | 0 1 | 2e+56 | 29 | 29 | 0 1 | 2e+57 | 29 | 29 | 0 1 | 2e+58 | 30 | 30 | 0 1 | 2e+59 | 30 | 30 | 0 1 | 2e+60 | 31 | 31 | 0 1 | 2e+61 | 31 | 31 | 0 1 | 2e+62 | 32 | 32 | 0 1 | 2e+63 | 32 | 32 | 0 1 | 2e+64 | 33 | 33 | 0 1 | 2e+65 | 33 | 33 | 0 1 | 2e+66 | 34 | 34 | 0 1 | 2e+67 | 34 | 34 | 0 1 | 2e+68 | 35 | 35 | 0 1 | 2e+69 | 35 | 35 | 0 1 | 2e+70 | 36 | 36 | 0 1 | 2e+71 | 36 | 36 | 0 1 | 2e+72 | 37 | 37 | 0 1 | 2e+73 | 37 | 37 | 0 1 | 2e+74 | 38 | 38 | 0 1 | 2e+75 | 38 | 38 | 0 1 | 2e+76 | 39 | 39 | 0 1 | 2e+77 | 39 | 39 | 0 1 | 2e+78 | 40 | 40 | 0 1 | 2e+79 | 40 | 40 | 0 1 | 2e+80 | 41 | 41 | 0 1 | 2e+81 | 41 | 41 | 0 1 | 2e+82 | 42 | 42 | 0 1 | 2e+83 | 42 | 42 | 0 1 | 2e+84 | 43 | 43 | 0 1 | 2e+85 | 43 | 43 | 0 1 | 2e+86 | 44 | 44 | 0 1 | 2e+87 | 44 | 44 | 0 1 | 2e+88 | 45 | 45 | 0 1 | 2e+89 | 45 | 45 | 0 1 | 2e+90 | 46 | 46 | 0 1 | 2e+91 | 46 | 46 | 0 1 | 2e+92 | 47 | 47 | 0 1 | 2e+93 | 47 | 47 | 0 1 | 2e+94 | 48 | 48 | 0 1 | 2e+95 | 48 | 48 | 0 1 | 2e+96 | 49 | 49 | 0 1 | 2e+97 | 49 | 49 | 0 1 | 2e+98 | 50 | 50 | 0 1 | 2e+99 | 50 | 50 | 0 1 | 2e+100 | 51 | 51 | 0 (201 rows) -- -- Comparison of sig_figs(sqrt(n)) for HEAD vs fix-sweight-v4 -- when DEC_DIGITS == 2 -- DEC_DIGITS | n | HEAD | fix-sweight-v4 | diff ------------+--------------+------+----------------+------ 2 | 2e-100 | 51 | 51 | 0 2 | 2e-99 | 50 | 50 | 0 2 | 2e-98 | 50 | 50 | 0 2 | 2e-97 | 49 | 49 | 0 2 | 2e-96 | 49 | 49 | 0 2 | 2e-95 | 48 | 48 | 0 2 | 2e-94 | 48 | 48 | 0 2 | 2e-93 | 47 | 47 | 0 2 | 2e-92 | 47 | 47 | 0 2 | 2e-91 | 46 | 46 | 0 2 | 2e-90 | 46 | 46 | 0 2 | 2e-89 | 45 | 45 | 0 2 | 2e-88 | 45 | 45 | 0 2 | 2e-87 | 44 | 44 | 0 2 | 2e-86 | 44 | 44 | 0 2 | 2e-85 | 43 | 43 | 0 2 | 2e-84 | 43 | 43 | 0 2 | 2e-83 | 42 | 42 | 0 2 | 2e-82 | 42 | 42 | 0 2 | 2e-81 | 41 | 41 | 0 2 | 2e-80 | 41 | 41 | 0 2 | 2e-79 | 40 | 40 | 0 2 | 2e-78 | 40 | 40 | 0 2 | 2e-77 | 39 | 39 | 0 2 | 2e-76 | 39 | 39 | 0 2 | 2e-75 | 38 | 38 | 0 2 | 2e-74 | 38 | 38 | 0 2 | 2e-73 | 37 | 37 | 0 2 | 2e-72 | 37 | 37 | 0 2 | 2e-71 | 36 | 36 | 0 2 | 2e-70 | 36 | 36 | 0 2 | 2e-69 | 35 | 35 | 0 2 | 2e-68 | 35 | 35 | 0 2 | 2e-67 | 34 | 34 | 0 2 | 2e-66 | 34 | 34 | 0 2 | 2e-65 | 33 | 33 | 0 2 | 2e-64 | 33 | 33 | 0 2 | 2e-63 | 32 | 32 | 0 2 | 2e-62 | 32 | 32 | 0 2 | 2e-61 | 31 | 31 | 0 2 | 2e-60 | 31 | 31 | 0 2 | 2e-59 | 30 | 30 | 0 2 | 2e-58 | 30 | 30 | 0 2 | 2e-57 | 29 | 29 | 0 2 | 2e-56 | 29 | 29 | 0 2 | 2e-55 | 28 | 28 | 0 2 | 2e-54 | 28 | 28 | 0 2 | 2e-53 | 27 | 27 | 0 2 | 2e-52 | 27 | 27 | 0 2 | 2e-51 | 26 | 26 | 0 2 | 2e-50 | 26 | 26 | 0 2 | 2e-49 | 25 | 25 | 0 2 | 2e-48 | 25 | 25 | 0 2 | 2e-47 | 24 | 24 | 0 2 | 2e-46 | 24 | 24 | 0 2 | 2e-45 | 23 | 23 | 0 2 | 2e-44 | 23 | 23 | 0 2 | 2e-43 | 22 | 22 | 0 2 | 2e-42 | 22 | 22 | 0 2 | 2e-41 | 21 | 21 | 0 2 | 2e-40 | 21 | 21 | 0 2 | 2e-39 | 20 | 20 | 0 2 | 2e-38 | 20 | 20 | 0 2 | 2e-37 | 19 | 19 | 0 2 | 2e-36 | 19 | 19 | 0 2 | 2e-35 | 18 | 18 | 0 2 | 2e-34 | 18 | 18 | 0 2 | 2e-33 | 17 | 17 | 0 2 | 2e-32 | 17 | 17 | 0 2 | 2e-31 | 17 | 16 | -1 2 | 2e-30 | 17 | 16 | -1 2 | 2e-29 | 17 | 16 | -1 2 | 2e-28 | 17 | 16 | -1 2 | 2e-27 | 17 | 16 | -1 2 | 2e-26 | 17 | 16 | -1 2 | 2e-25 | 17 | 16 | -1 2 | 2e-24 | 17 | 16 | -1 2 | 2e-23 | 17 | 16 | -1 2 | 2e-22 | 17 | 16 | -1 2 | 2e-21 | 17 | 16 | -1 2 | 2e-20 | 17 | 16 | -1 2 | 2e-19 | 17 | 16 | -1 2 | 2e-18 | 17 | 16 | -1 2 | 2e-17 | 17 | 16 | -1 2 | 2e-16 | 17 | 16 | -1 2 | 2e-15 | 17 | 16 | -1 2 | 2e-14 | 17 | 16 | -1 2 | 2e-13 | 17 | 16 | -1 2 | 2e-12 | 17 | 16 | -1 2 | 2e-11 | 17 | 16 | -1 2 | 0.0000000002 | 17 | 16 | -1 2 | 0.000000002 | 17 | 16 | -1 2 | 0.00000002 | 17 | 16 | -1 2 | 0.0000002 | 17 | 16 | -1 2 | 0.000002 | 17 | 16 | -1 2 | 0.00002 | 17 | 16 | -1 2 | 0.0002 | 17 | 16 | -1 2 | 0.002 | 17 | 16 | -1 2 | 0.02 | 17 | 16 | -1 2 | 0.2 | 17 | 16 | -1 2 | 2 | 17 | 16 | -1 2 | 20 | 17 | 16 | -1 2 | 200 | 17 | 16 | -1 2 | 2000 | 17 | 16 | -1 2 | 20000 | 17 | 16 | -1 2 | 200000 | 17 | 16 | -1 2 | 2000000 | 17 | 16 | -1 2 | 20000000 | 17 | 16 | -1 2 | 200000000 | 17 | 16 | -1 2 | 2000000000 | 17 | 16 | -1 2 | 20000000000 | 17 | 16 | -1 2 | 2e+11 | 17 | 16 | -1 2 | 2e+12 | 17 | 16 | -1 2 | 2e+13 | 17 | 16 | -1 2 | 2e+14 | 17 | 16 | -1 2 | 2e+15 | 17 | 16 | -1 2 | 2e+16 | 17 | 16 | -1 2 | 2e+17 | 17 | 16 | -1 2 | 2e+18 | 17 | 16 | -1 2 | 2e+19 | 17 | 16 | -1 2 | 2e+20 | 17 | 16 | -1 2 | 2e+21 | 17 | 16 | -1 2 | 2e+22 | 17 | 16 | -1 2 | 2e+23 | 17 | 16 | -1 2 | 2e+24 | 17 | 16 | -1 2 | 2e+25 | 17 | 16 | -1 2 | 2e+26 | 17 | 16 | -1 2 | 2e+27 | 17 | 16 | -1 2 | 2e+28 | 17 | 16 | -1 2 | 2e+29 | 17 | 16 | -1 2 | 2e+30 | 17 | 16 | -1 2 | 2e+31 | 17 | 16 | -1 2 | 2e+32 | 17 | 17 | 0 2 | 2e+33 | 17 | 17 | 0 2 | 2e+34 | 18 | 18 | 0 2 | 2e+35 | 18 | 18 | 0 2 | 2e+36 | 19 | 19 | 0 2 | 2e+37 | 19 | 19 | 0 2 | 2e+38 | 20 | 20 | 0 2 | 2e+39 | 20 | 20 | 0 2 | 2e+40 | 21 | 21 | 0 2 | 2e+41 | 21 | 21 | 0 2 | 2e+42 | 22 | 22 | 0 2 | 2e+43 | 22 | 22 | 0 2 | 2e+44 | 23 | 23 | 0 2 | 2e+45 | 23 | 23 | 0 2 | 2e+46 | 24 | 24 | 0 2 | 2e+47 | 24 | 24 | 0 2 | 2e+48 | 25 | 25 | 0 2 | 2e+49 | 25 | 25 | 0 2 | 2e+50 | 26 | 26 | 0 2 | 2e+51 | 26 | 26 | 0 2 | 2e+52 | 27 | 27 | 0 2 | 2e+53 | 27 | 27 | 0 2 | 2e+54 | 28 | 28 | 0 2 | 2e+55 | 28 | 28 | 0 2 | 2e+56 | 29 | 29 | 0 2 | 2e+57 | 29 | 29 | 0 2 | 2e+58 | 30 | 30 | 0 2 | 2e+59 | 30 | 30 | 0 2 | 2e+60 | 31 | 31 | 0 2 | 2e+61 | 31 | 31 | 0 2 | 2e+62 | 32 | 32 | 0 2 | 2e+63 | 32 | 32 | 0 2 | 2e+64 | 33 | 33 | 0 2 | 2e+65 | 33 | 33 | 0 2 | 2e+66 | 34 | 34 | 0 2 | 2e+67 | 34 | 34 | 0 2 | 2e+68 | 35 | 35 | 0 2 | 2e+69 | 35 | 35 | 0 2 | 2e+70 | 36 | 36 | 0 2 | 2e+71 | 36 | 36 | 0 2 | 2e+72 | 37 | 37 | 0 2 | 2e+73 | 37 | 37 | 0 2 | 2e+74 | 38 | 38 | 0 2 | 2e+75 | 38 | 38 | 0 2 | 2e+76 | 39 | 39 | 0 2 | 2e+77 | 39 | 39 | 0 2 | 2e+78 | 40 | 40 | 0 2 | 2e+79 | 40 | 40 | 0 2 | 2e+80 | 41 | 41 | 0 2 | 2e+81 | 41 | 41 | 0 2 | 2e+82 | 42 | 42 | 0 2 | 2e+83 | 42 | 42 | 0 2 | 2e+84 | 43 | 43 | 0 2 | 2e+85 | 43 | 43 | 0 2 | 2e+86 | 44 | 44 | 0 2 | 2e+87 | 44 | 44 | 0 2 | 2e+88 | 45 | 45 | 0 2 | 2e+89 | 45 | 45 | 0 2 | 2e+90 | 46 | 46 | 0 2 | 2e+91 | 46 | 46 | 0 2 | 2e+92 | 47 | 47 | 0 2 | 2e+93 | 47 | 47 | 0 2 | 2e+94 | 48 | 48 | 0 2 | 2e+95 | 48 | 48 | 0 2 | 2e+96 | 49 | 49 | 0 2 | 2e+97 | 49 | 49 | 0 2 | 2e+98 | 50 | 50 | 0 2 | 2e+99 | 50 | 50 | 0 2 | 2e+100 | 51 | 51 | 0 (201 rows) -- -- Comparison of sig_figs(sqrt(n)) for HEAD vs fix-sweight-v4 -- when DEC_DIGITS == 4 -- DEC_DIGITS | n | HEAD | fix-sweight-v4 | diff ------------+--------------+------+----------------+------ 4 | 2e-100 | 51 | 51 | 0 4 | 2e-99 | 50 | 50 | 0 4 | 2e-98 | 50 | 50 | 0 4 | 2e-97 | 49 | 49 | 0 4 | 2e-96 | 49 | 49 | 0 4 | 2e-95 | 48 | 48 | 0 4 | 2e-94 | 48 | 48 | 0 4 | 2e-93 | 47 | 47 | 0 4 | 2e-92 | 47 | 47 | 0 4 | 2e-91 | 46 | 46 | 0 4 | 2e-90 | 46 | 46 | 0 4 | 2e-89 | 45 | 45 | 0 4 | 2e-88 | 45 | 45 | 0 4 | 2e-87 | 44 | 44 | 0 4 | 2e-86 | 44 | 44 | 0 4 | 2e-85 | 43 | 43 | 0 4 | 2e-84 | 43 | 43 | 0 4 | 2e-83 | 42 | 42 | 0 4 | 2e-82 | 42 | 42 | 0 4 | 2e-81 | 41 | 41 | 0 4 | 2e-80 | 41 | 41 | 0 4 | 2e-79 | 40 | 40 | 0 4 | 2e-78 | 40 | 40 | 0 4 | 2e-77 | 39 | 39 | 0 4 | 2e-76 | 39 | 39 | 0 4 | 2e-75 | 38 | 38 | 0 4 | 2e-74 | 38 | 38 | 0 4 | 2e-73 | 37 | 37 | 0 4 | 2e-72 | 37 | 37 | 0 4 | 2e-71 | 36 | 36 | 0 4 | 2e-70 | 36 | 36 | 0 4 | 2e-69 | 35 | 35 | 0 4 | 2e-68 | 35 | 35 | 0 4 | 2e-67 | 34 | 34 | 0 4 | 2e-66 | 34 | 34 | 0 4 | 2e-65 | 33 | 33 | 0 4 | 2e-64 | 33 | 33 | 0 4 | 2e-63 | 32 | 32 | 0 4 | 2e-62 | 32 | 32 | 0 4 | 2e-61 | 31 | 31 | 0 4 | 2e-60 | 31 | 31 | 0 4 | 2e-59 | 30 | 30 | 0 4 | 2e-58 | 30 | 30 | 0 4 | 2e-57 | 29 | 29 | 0 4 | 2e-56 | 29 | 29 | 0 4 | 2e-55 | 28 | 28 | 0 4 | 2e-54 | 28 | 28 | 0 4 | 2e-53 | 27 | 27 | 0 4 | 2e-52 | 27 | 27 | 0 4 | 2e-51 | 26 | 26 | 0 4 | 2e-50 | 26 | 26 | 0 4 | 2e-49 | 25 | 25 | 0 4 | 2e-48 | 25 | 25 | 0 4 | 2e-47 | 24 | 24 | 0 4 | 2e-46 | 24 | 24 | 0 4 | 2e-45 | 23 | 23 | 0 4 | 2e-44 | 23 | 23 | 0 4 | 2e-43 | 22 | 22 | 0 4 | 2e-42 | 22 | 22 | 0 4 | 2e-41 | 21 | 21 | 0 4 | 2e-40 | 21 | 21 | 0 4 | 2e-39 | 20 | 20 | 0 4 | 2e-38 | 20 | 20 | 0 4 | 2e-37 | 19 | 19 | 0 4 | 2e-36 | 19 | 19 | 0 4 | 2e-35 | 18 | 18 | 0 4 | 2e-34 | 18 | 18 | 0 4 | 2e-33 | 17 | 17 | 0 4 | 2e-32 | 17 | 17 | 0 4 | 2e-31 | 16 | 16 | 0 4 | 2e-30 | 17 | 17 | 0 4 | 2e-29 | 17 | 17 | 0 4 | 2e-28 | 16 | 16 | 0 4 | 2e-27 | 16 | 16 | 0 4 | 2e-26 | 17 | 17 | 0 4 | 2e-25 | 17 | 17 | 0 4 | 2e-24 | 16 | 16 | 0 4 | 2e-23 | 16 | 16 | 0 4 | 2e-22 | 17 | 17 | 0 4 | 2e-21 | 17 | 17 | 0 4 | 2e-20 | 16 | 16 | 0 4 | 2e-19 | 16 | 16 | 0 4 | 2e-18 | 17 | 17 | 0 4 | 2e-17 | 17 | 17 | 0 4 | 2e-16 | 16 | 16 | 0 4 | 2e-15 | 16 | 16 | 0 4 | 2e-14 | 17 | 17 | 0 4 | 2e-13 | 17 | 17 | 0 4 | 2e-12 | 16 | 16 | 0 4 | 2e-11 | 16 | 16 | 0 4 | 0.0000000002 | 17 | 17 | 0 4 | 0.000000002 | 17 | 17 | 0 4 | 0.00000002 | 16 | 16 | 0 4 | 0.0000002 | 16 | 16 | 0 4 | 0.000002 | 17 | 17 | 0 4 | 0.00002 | 17 | 17 | 0 4 | 0.0002 | 16 | 16 | 0 4 | 0.002 | 16 | 16 | 0 4 | 0.02 | 17 | 17 | 0 4 | 0.2 | 17 | 17 | 0 4 | 2 | 16 | 16 | 0 4 | 20 | 16 | 16 | 0 4 | 200 | 17 | 17 | 0 4 | 2000 | 17 | 17 | 0 4 | 20000 | 16 | 16 | 0 4 | 200000 | 16 | 16 | 0 4 | 2000000 | 17 | 17 | 0 4 | 20000000 | 17 | 17 | 0 4 | 200000000 | 16 | 16 | 0 4 | 2000000000 | 16 | 16 | 0 4 | 20000000000 | 17 | 17 | 0 4 | 2e+11 | 17 | 17 | 0 4 | 2e+12 | 16 | 16 | 0 4 | 2e+13 | 16 | 16 | 0 4 | 2e+14 | 17 | 17 | 0 4 | 2e+15 | 17 | 17 | 0 4 | 2e+16 | 16 | 16 | 0 4 | 2e+17 | 16 | 16 | 0 4 | 2e+18 | 17 | 17 | 0 4 | 2e+19 | 17 | 17 | 0 4 | 2e+20 | 16 | 16 | 0 4 | 2e+21 | 16 | 16 | 0 4 | 2e+22 | 17 | 17 | 0 4 | 2e+23 | 17 | 17 | 0 4 | 2e+24 | 16 | 16 | 0 4 | 2e+25 | 16 | 16 | 0 4 | 2e+26 | 17 | 17 | 0 4 | 2e+27 | 17 | 17 | 0 4 | 2e+28 | 16 | 16 | 0 4 | 2e+29 | 16 | 16 | 0 4 | 2e+30 | 17 | 17 | 0 4 | 2e+31 | 17 | 17 | 0 4 | 2e+32 | 17 | 17 | 0 4 | 2e+33 | 17 | 17 | 0 4 | 2e+34 | 18 | 18 | 0 4 | 2e+35 | 18 | 18 | 0 4 | 2e+36 | 19 | 19 | 0 4 | 2e+37 | 19 | 19 | 0 4 | 2e+38 | 20 | 20 | 0 4 | 2e+39 | 20 | 20 | 0 4 | 2e+40 | 21 | 21 | 0 4 | 2e+41 | 21 | 21 | 0 4 | 2e+42 | 22 | 22 | 0 4 | 2e+43 | 22 | 22 | 0 4 | 2e+44 | 23 | 23 | 0 4 | 2e+45 | 23 | 23 | 0 4 | 2e+46 | 24 | 24 | 0 4 | 2e+47 | 24 | 24 | 0 4 | 2e+48 | 25 | 25 | 0 4 | 2e+49 | 25 | 25 | 0 4 | 2e+50 | 26 | 26 | 0 4 | 2e+51 | 26 | 26 | 0 4 | 2e+52 | 27 | 27 | 0 4 | 2e+53 | 27 | 27 | 0 4 | 2e+54 | 28 | 28 | 0 4 | 2e+55 | 28 | 28 | 0 4 | 2e+56 | 29 | 29 | 0 4 | 2e+57 | 29 | 29 | 0 4 | 2e+58 | 30 | 30 | 0 4 | 2e+59 | 30 | 30 | 0 4 | 2e+60 | 31 | 31 | 0 4 | 2e+61 | 31 | 31 | 0 4 | 2e+62 | 32 | 32 | 0 4 | 2e+63 | 32 | 32 | 0 4 | 2e+64 | 33 | 33 | 0 4 | 2e+65 | 33 | 33 | 0 4 | 2e+66 | 34 | 34 | 0 4 | 2e+67 | 34 | 34 | 0 4 | 2e+68 | 35 | 35 | 0 4 | 2e+69 | 35 | 35 | 0 4 | 2e+70 | 36 | 36 | 0 4 | 2e+71 | 36 | 36 | 0 4 | 2e+72 | 37 | 37 | 0 4 | 2e+73 | 37 | 37 | 0 4 | 2e+74 | 38 | 38 | 0 4 | 2e+75 | 38 | 38 | 0 4 | 2e+76 | 39 | 39 | 0 4 | 2e+77 | 39 | 39 | 0 4 | 2e+78 | 40 | 40 | 0 4 | 2e+79 | 40 | 40 | 0 4 | 2e+80 | 41 | 41 | 0 4 | 2e+81 | 41 | 41 | 0 4 | 2e+82 | 42 | 42 | 0 4 | 2e+83 | 42 | 42 | 0 4 | 2e+84 | 43 | 43 | 0 4 | 2e+85 | 43 | 43 | 0 4 | 2e+86 | 44 | 44 | 0 4 | 2e+87 | 44 | 44 | 0 4 | 2e+88 | 45 | 45 | 0 4 | 2e+89 | 45 | 45 | 0 4 | 2e+90 | 46 | 46 | 0 4 | 2e+91 | 46 | 46 | 0 4 | 2e+92 | 47 | 47 | 0 4 | 2e+93 | 47 | 47 | 0 4 | 2e+94 | 48 | 48 | 0 4 | 2e+95 | 48 | 48 | 0 4 | 2e+96 | 49 | 49 | 0 4 | 2e+97 | 49 | 49 | 0 4 | 2e+98 | 50 | 50 | 0 4 | 2e+99 | 50 | 50 | 0 4 | 2e+100 | 51 | 51 | 0 (201 rows) Attachments: [application/octet-stream] fix-sweight-v4.patch (1020B, ../../[email protected]/2-fix-sweight-v4.patch) download | inline diff: diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c index 898c52099b..a11ab8aa37 100644 --- a/src/backend/utils/adt/numeric.c +++ b/src/backend/utils/adt/numeric.c @@ -3693,8 +3693,21 @@ numeric_sqrt(PG_FUNCTION_ARGS) init_var(&result); - /* Assume the input was normalized, so arg.weight is accurate */ - sweight = (arg.weight + 1) * DEC_DIGITS / 2 - 1; + /* + * Assume the input was normalized, so arg.weight is accurate. The result + * then has at least sweight = floor(arg.weight * DEC_DIGITS / 2 + 1) + * digits before the decimal point. When DEC_DIGITS is even, we can save + * a few cycles, since the division is exact and there is no need to + * round down. + */ +#if DEC_DIGITS == ((DEC_DIGITS / 2) * 2) + sweight = arg.weight * DEC_DIGITS / 2 + 1; +#else + if (arg.weight >= 0) + sweight = arg.weight * DEC_DIGITS / 2 + 1; + else + sweight = 1 - (1 - arg.weight * DEC_DIGITS) / 2; +#endif rscale = NUMERIC_MIN_SIG_DIGITS - sweight; rscale = Max(rscale, arg.dscale); [text/plain] fix-sweight-v4-test-output.txt (34.8K, ../../[email protected]/3-fix-sweight-v4-test-output.txt) download | inline: -- -- Comparison of sig_figs(sqrt(n)) for HEAD vs fix-sweight-v4 -- when DEC_DIGITS == 1 -- DEC_DIGITS | n | HEAD | fix-sweight-v4 | diff ------------+--------------+------+----------------+------ 1 | 2e-100 | 51 | 51 | 0 1 | 2e-99 | 50 | 50 | 0 1 | 2e-98 | 50 | 50 | 0 1 | 2e-97 | 49 | 49 | 0 1 | 2e-96 | 49 | 49 | 0 1 | 2e-95 | 48 | 48 | 0 1 | 2e-94 | 48 | 48 | 0 1 | 2e-93 | 47 | 47 | 0 1 | 2e-92 | 47 | 47 | 0 1 | 2e-91 | 46 | 46 | 0 1 | 2e-90 | 46 | 46 | 0 1 | 2e-89 | 45 | 45 | 0 1 | 2e-88 | 45 | 45 | 0 1 | 2e-87 | 44 | 44 | 0 1 | 2e-86 | 44 | 44 | 0 1 | 2e-85 | 43 | 43 | 0 1 | 2e-84 | 43 | 43 | 0 1 | 2e-83 | 42 | 42 | 0 1 | 2e-82 | 42 | 42 | 0 1 | 2e-81 | 41 | 41 | 0 1 | 2e-80 | 41 | 41 | 0 1 | 2e-79 | 40 | 40 | 0 1 | 2e-78 | 40 | 40 | 0 1 | 2e-77 | 39 | 39 | 0 1 | 2e-76 | 39 | 39 | 0 1 | 2e-75 | 38 | 38 | 0 1 | 2e-74 | 38 | 38 | 0 1 | 2e-73 | 37 | 37 | 0 1 | 2e-72 | 37 | 37 | 0 1 | 2e-71 | 36 | 36 | 0 1 | 2e-70 | 36 | 36 | 0 1 | 2e-69 | 35 | 35 | 0 1 | 2e-68 | 35 | 35 | 0 1 | 2e-67 | 34 | 34 | 0 1 | 2e-66 | 34 | 34 | 0 1 | 2e-65 | 33 | 33 | 0 1 | 2e-64 | 33 | 33 | 0 1 | 2e-63 | 32 | 32 | 0 1 | 2e-62 | 32 | 32 | 0 1 | 2e-61 | 31 | 31 | 0 1 | 2e-60 | 31 | 31 | 0 1 | 2e-59 | 30 | 30 | 0 1 | 2e-58 | 30 | 30 | 0 1 | 2e-57 | 29 | 29 | 0 1 | 2e-56 | 29 | 29 | 0 1 | 2e-55 | 28 | 28 | 0 1 | 2e-54 | 28 | 28 | 0 1 | 2e-53 | 27 | 27 | 0 1 | 2e-52 | 27 | 27 | 0 1 | 2e-51 | 26 | 26 | 0 1 | 2e-50 | 26 | 26 | 0 1 | 2e-49 | 25 | 25 | 0 1 | 2e-48 | 25 | 25 | 0 1 | 2e-47 | 24 | 24 | 0 1 | 2e-46 | 24 | 24 | 0 1 | 2e-45 | 23 | 23 | 0 1 | 2e-44 | 23 | 23 | 0 1 | 2e-43 | 22 | 22 | 0 1 | 2e-42 | 22 | 22 | 0 1 | 2e-41 | 21 | 21 | 0 1 | 2e-40 | 21 | 21 | 0 1 | 2e-39 | 20 | 20 | 0 1 | 2e-38 | 20 | 20 | 0 1 | 2e-37 | 19 | 19 | 0 1 | 2e-36 | 19 | 19 | 0 1 | 2e-35 | 18 | 18 | 0 1 | 2e-34 | 18 | 18 | 0 1 | 2e-33 | 17 | 17 | 0 1 | 2e-32 | 17 | 17 | 0 1 | 2e-31 | 17 | 16 | -1 1 | 2e-30 | 17 | 16 | -1 1 | 2e-29 | 17 | 16 | -1 1 | 2e-28 | 17 | 16 | -1 1 | 2e-27 | 17 | 16 | -1 1 | 2e-26 | 17 | 16 | -1 1 | 2e-25 | 17 | 16 | -1 1 | 2e-24 | 17 | 16 | -1 1 | 2e-23 | 17 | 16 | -1 1 | 2e-22 | 17 | 16 | -1 1 | 2e-21 | 17 | 16 | -1 1 | 2e-20 | 17 | 16 | -1 1 | 2e-19 | 17 | 16 | -1 1 | 2e-18 | 17 | 16 | -1 1 | 2e-17 | 17 | 16 | -1 1 | 2e-16 | 17 | 16 | -1 1 | 2e-15 | 17 | 16 | -1 1 | 2e-14 | 17 | 16 | -1 1 | 2e-13 | 17 | 16 | -1 1 | 2e-12 | 17 | 16 | -1 1 | 2e-11 | 17 | 16 | -1 1 | 0.0000000002 | 17 | 16 | -1 1 | 0.000000002 | 17 | 16 | -1 1 | 0.00000002 | 17 | 16 | -1 1 | 0.0000002 | 17 | 16 | -1 1 | 0.000002 | 17 | 16 | -1 1 | 0.00002 | 17 | 16 | -1 1 | 0.0002 | 17 | 16 | -1 1 | 0.002 | 17 | 16 | -1 1 | 0.02 | 17 | 16 | -1 1 | 0.2 | 17 | 16 | -1 1 | 2 | 18 | 16 | -2 1 | 20 | 17 | 16 | -1 1 | 200 | 18 | 16 | -2 1 | 2000 | 17 | 16 | -1 1 | 20000 | 18 | 16 | -2 1 | 200000 | 17 | 16 | -1 1 | 2000000 | 18 | 16 | -2 1 | 20000000 | 17 | 16 | -1 1 | 200000000 | 18 | 16 | -2 1 | 2000000000 | 17 | 16 | -1 1 | 20000000000 | 18 | 16 | -2 1 | 2e+11 | 17 | 16 | -1 1 | 2e+12 | 18 | 16 | -2 1 | 2e+13 | 17 | 16 | -1 1 | 2e+14 | 18 | 16 | -2 1 | 2e+15 | 17 | 16 | -1 1 | 2e+16 | 18 | 16 | -2 1 | 2e+17 | 17 | 16 | -1 1 | 2e+18 | 18 | 16 | -2 1 | 2e+19 | 17 | 16 | -1 1 | 2e+20 | 18 | 16 | -2 1 | 2e+21 | 17 | 16 | -1 1 | 2e+22 | 18 | 16 | -2 1 | 2e+23 | 17 | 16 | -1 1 | 2e+24 | 18 | 16 | -2 1 | 2e+25 | 17 | 16 | -1 1 | 2e+26 | 18 | 16 | -2 1 | 2e+27 | 17 | 16 | -1 1 | 2e+28 | 18 | 16 | -2 1 | 2e+29 | 17 | 16 | -1 1 | 2e+30 | 18 | 16 | -2 1 | 2e+31 | 17 | 16 | -1 1 | 2e+32 | 18 | 17 | -1 1 | 2e+33 | 17 | 17 | 0 1 | 2e+34 | 18 | 18 | 0 1 | 2e+35 | 18 | 18 | 0 1 | 2e+36 | 19 | 19 | 0 1 | 2e+37 | 19 | 19 | 0 1 | 2e+38 | 20 | 20 | 0 1 | 2e+39 | 20 | 20 | 0 1 | 2e+40 | 21 | 21 | 0 1 | 2e+41 | 21 | 21 | 0 1 | 2e+42 | 22 | 22 | 0 1 | 2e+43 | 22 | 22 | 0 1 | 2e+44 | 23 | 23 | 0 1 | 2e+45 | 23 | 23 | 0 1 | 2e+46 | 24 | 24 | 0 1 | 2e+47 | 24 | 24 | 0 1 | 2e+48 | 25 | 25 | 0 1 | 2e+49 | 25 | 25 | 0 1 | 2e+50 | 26 | 26 | 0 1 | 2e+51 | 26 | 26 | 0 1 | 2e+52 | 27 | 27 | 0 1 | 2e+53 | 27 | 27 | 0 1 | 2e+54 | 28 | 28 | 0 1 | 2e+55 | 28 | 28 | 0 1 | 2e+56 | 29 | 29 | 0 1 | 2e+57 | 29 | 29 | 0 1 | 2e+58 | 30 | 30 | 0 1 | 2e+59 | 30 | 30 | 0 1 | 2e+60 | 31 | 31 | 0 1 | 2e+61 | 31 | 31 | 0 1 | 2e+62 | 32 | 32 | 0 1 | 2e+63 | 32 | 32 | 0 1 | 2e+64 | 33 | 33 | 0 1 | 2e+65 | 33 | 33 | 0 1 | 2e+66 | 34 | 34 | 0 1 | 2e+67 | 34 | 34 | 0 1 | 2e+68 | 35 | 35 | 0 1 | 2e+69 | 35 | 35 | 0 1 | 2e+70 | 36 | 36 | 0 1 | 2e+71 | 36 | 36 | 0 1 | 2e+72 | 37 | 37 | 0 1 | 2e+73 | 37 | 37 | 0 1 | 2e+74 | 38 | 38 | 0 1 | 2e+75 | 38 | 38 | 0 1 | 2e+76 | 39 | 39 | 0 1 | 2e+77 | 39 | 39 | 0 1 | 2e+78 | 40 | 40 | 0 1 | 2e+79 | 40 | 40 | 0 1 | 2e+80 | 41 | 41 | 0 1 | 2e+81 | 41 | 41 | 0 1 | 2e+82 | 42 | 42 | 0 1 | 2e+83 | 42 | 42 | 0 1 | 2e+84 | 43 | 43 | 0 1 | 2e+85 | 43 | 43 | 0 1 | 2e+86 | 44 | 44 | 0 1 | 2e+87 | 44 | 44 | 0 1 | 2e+88 | 45 | 45 | 0 1 | 2e+89 | 45 | 45 | 0 1 | 2e+90 | 46 | 46 | 0 1 | 2e+91 | 46 | 46 | 0 1 | 2e+92 | 47 | 47 | 0 1 | 2e+93 | 47 | 47 | 0 1 | 2e+94 | 48 | 48 | 0 1 | 2e+95 | 48 | 48 | 0 1 | 2e+96 | 49 | 49 | 0 1 | 2e+97 | 49 | 49 | 0 1 | 2e+98 | 50 | 50 | 0 1 | 2e+99 | 50 | 50 | 0 1 | 2e+100 | 51 | 51 | 0 (201 rows) -- -- Comparison of sig_figs(sqrt(n)) for HEAD vs fix-sweight-v4 -- when DEC_DIGITS == 2 -- DEC_DIGITS | n | HEAD | fix-sweight-v4 | diff ------------+--------------+------+----------------+------ 2 | 2e-100 | 51 | 51 | 0 2 | 2e-99 | 50 | 50 | 0 2 | 2e-98 | 50 | 50 | 0 2 | 2e-97 | 49 | 49 | 0 2 | 2e-96 | 49 | 49 | 0 2 | 2e-95 | 48 | 48 | 0 2 | 2e-94 | 48 | 48 | 0 2 | 2e-93 | 47 | 47 | 0 2 | 2e-92 | 47 | 47 | 0 2 | 2e-91 | 46 | 46 | 0 2 | 2e-90 | 46 | 46 | 0 2 | 2e-89 | 45 | 45 | 0 2 | 2e-88 | 45 | 45 | 0 2 | 2e-87 | 44 | 44 | 0 2 | 2e-86 | 44 | 44 | 0 2 | 2e-85 | 43 | 43 | 0 2 | 2e-84 | 43 | 43 | 0 2 | 2e-83 | 42 | 42 | 0 2 | 2e-82 | 42 | 42 | 0 2 | 2e-81 | 41 | 41 | 0 2 | 2e-80 | 41 | 41 | 0 2 | 2e-79 | 40 | 40 | 0 2 | 2e-78 | 40 | 40 | 0 2 | 2e-77 | 39 | 39 | 0 2 | 2e-76 | 39 | 39 | 0 2 | 2e-75 | 38 | 38 | 0 2 | 2e-74 | 38 | 38 | 0 2 | 2e-73 | 37 | 37 | 0 2 | 2e-72 | 37 | 37 | 0 2 | 2e-71 | 36 | 36 | 0 2 | 2e-70 | 36 | 36 | 0 2 | 2e-69 | 35 | 35 | 0 2 | 2e-68 | 35 | 35 | 0 2 | 2e-67 | 34 | 34 | 0 2 | 2e-66 | 34 | 34 | 0 2 | 2e-65 | 33 | 33 | 0 2 | 2e-64 | 33 | 33 | 0 2 | 2e-63 | 32 | 32 | 0 2 | 2e-62 | 32 | 32 | 0 2 | 2e-61 | 31 | 31 | 0 2 | 2e-60 | 31 | 31 | 0 2 | 2e-59 | 30 | 30 | 0 2 | 2e-58 | 30 | 30 | 0 2 | 2e-57 | 29 | 29 | 0 2 | 2e-56 | 29 | 29 | 0 2 | 2e-55 | 28 | 28 | 0 2 | 2e-54 | 28 | 28 | 0 2 | 2e-53 | 27 | 27 | 0 2 | 2e-52 | 27 | 27 | 0 2 | 2e-51 | 26 | 26 | 0 2 | 2e-50 | 26 | 26 | 0 2 | 2e-49 | 25 | 25 | 0 2 | 2e-48 | 25 | 25 | 0 2 | 2e-47 | 24 | 24 | 0 2 | 2e-46 | 24 | 24 | 0 2 | 2e-45 | 23 | 23 | 0 2 | 2e-44 | 23 | 23 | 0 2 | 2e-43 | 22 | 22 | 0 2 | 2e-42 | 22 | 22 | 0 2 | 2e-41 | 21 | 21 | 0 2 | 2e-40 | 21 | 21 | 0 2 | 2e-39 | 20 | 20 | 0 2 | 2e-38 | 20 | 20 | 0 2 | 2e-37 | 19 | 19 | 0 2 | 2e-36 | 19 | 19 | 0 2 | 2e-35 | 18 | 18 | 0 2 | 2e-34 | 18 | 18 | 0 2 | 2e-33 | 17 | 17 | 0 2 | 2e-32 | 17 | 17 | 0 2 | 2e-31 | 17 | 16 | -1 2 | 2e-30 | 17 | 16 | -1 2 | 2e-29 | 17 | 16 | -1 2 | 2e-28 | 17 | 16 | -1 2 | 2e-27 | 17 | 16 | -1 2 | 2e-26 | 17 | 16 | -1 2 | 2e-25 | 17 | 16 | -1 2 | 2e-24 | 17 | 16 | -1 2 | 2e-23 | 17 | 16 | -1 2 | 2e-22 | 17 | 16 | -1 2 | 2e-21 | 17 | 16 | -1 2 | 2e-20 | 17 | 16 | -1 2 | 2e-19 | 17 | 16 | -1 2 | 2e-18 | 17 | 16 | -1 2 | 2e-17 | 17 | 16 | -1 2 | 2e-16 | 17 | 16 | -1 2 | 2e-15 | 17 | 16 | -1 2 | 2e-14 | 17 | 16 | -1 2 | 2e-13 | 17 | 16 | -1 2 | 2e-12 | 17 | 16 | -1 2 | 2e-11 | 17 | 16 | -1 2 | 0.0000000002 | 17 | 16 | -1 2 | 0.000000002 | 17 | 16 | -1 2 | 0.00000002 | 17 | 16 | -1 2 | 0.0000002 | 17 | 16 | -1 2 | 0.000002 | 17 | 16 | -1 2 | 0.00002 | 17 | 16 | -1 2 | 0.0002 | 17 | 16 | -1 2 | 0.002 | 17 | 16 | -1 2 | 0.02 | 17 | 16 | -1 2 | 0.2 | 17 | 16 | -1 2 | 2 | 17 | 16 | -1 2 | 20 | 17 | 16 | -1 2 | 200 | 17 | 16 | -1 2 | 2000 | 17 | 16 | -1 2 | 20000 | 17 | 16 | -1 2 | 200000 | 17 | 16 | -1 2 | 2000000 | 17 | 16 | -1 2 | 20000000 | 17 | 16 | -1 2 | 200000000 | 17 | 16 | -1 2 | 2000000000 | 17 | 16 | -1 2 | 20000000000 | 17 | 16 | -1 2 | 2e+11 | 17 | 16 | -1 2 | 2e+12 | 17 | 16 | -1 2 | 2e+13 | 17 | 16 | -1 2 | 2e+14 | 17 | 16 | -1 2 | 2e+15 | 17 | 16 | -1 2 | 2e+16 | 17 | 16 | -1 2 | 2e+17 | 17 | 16 | -1 2 | 2e+18 | 17 | 16 | -1 2 | 2e+19 | 17 | 16 | -1 2 | 2e+20 | 17 | 16 | -1 2 | 2e+21 | 17 | 16 | -1 2 | 2e+22 | 17 | 16 | -1 2 | 2e+23 | 17 | 16 | -1 2 | 2e+24 | 17 | 16 | -1 2 | 2e+25 | 17 | 16 | -1 2 | 2e+26 | 17 | 16 | -1 2 | 2e+27 | 17 | 16 | -1 2 | 2e+28 | 17 | 16 | -1 2 | 2e+29 | 17 | 16 | -1 2 | 2e+30 | 17 | 16 | -1 2 | 2e+31 | 17 | 16 | -1 2 | 2e+32 | 17 | 17 | 0 2 | 2e+33 | 17 | 17 | 0 2 | 2e+34 | 18 | 18 | 0 2 | 2e+35 | 18 | 18 | 0 2 | 2e+36 | 19 | 19 | 0 2 | 2e+37 | 19 | 19 | 0 2 | 2e+38 | 20 | 20 | 0 2 | 2e+39 | 20 | 20 | 0 2 | 2e+40 | 21 | 21 | 0 2 | 2e+41 | 21 | 21 | 0 2 | 2e+42 | 22 | 22 | 0 2 | 2e+43 | 22 | 22 | 0 2 | 2e+44 | 23 | 23 | 0 2 | 2e+45 | 23 | 23 | 0 2 | 2e+46 | 24 | 24 | 0 2 | 2e+47 | 24 | 24 | 0 2 | 2e+48 | 25 | 25 | 0 2 | 2e+49 | 25 | 25 | 0 2 | 2e+50 | 26 | 26 | 0 2 | 2e+51 | 26 | 26 | 0 2 | 2e+52 | 27 | 27 | 0 2 | 2e+53 | 27 | 27 | 0 2 | 2e+54 | 28 | 28 | 0 2 | 2e+55 | 28 | 28 | 0 2 | 2e+56 | 29 | 29 | 0 2 | 2e+57 | 29 | 29 | 0 2 | 2e+58 | 30 | 30 | 0 2 | 2e+59 | 30 | 30 | 0 2 | 2e+60 | 31 | 31 | 0 2 | 2e+61 | 31 | 31 | 0 2 | 2e+62 | 32 | 32 | 0 2 | 2e+63 | 32 | 32 | 0 2 | 2e+64 | 33 | 33 | 0 2 | 2e+65 | 33 | 33 | 0 2 | 2e+66 | 34 | 34 | 0 2 | 2e+67 | 34 | 34 | 0 2 | 2e+68 | 35 | 35 | 0 2 | 2e+69 | 35 | 35 | 0 2 | 2e+70 | 36 | 36 | 0 2 | 2e+71 | 36 | 36 | 0 2 | 2e+72 | 37 | 37 | 0 2 | 2e+73 | 37 | 37 | 0 2 | 2e+74 | 38 | 38 | 0 2 | 2e+75 | 38 | 38 | 0 2 | 2e+76 | 39 | 39 | 0 2 | 2e+77 | 39 | 39 | 0 2 | 2e+78 | 40 | 40 | 0 2 | 2e+79 | 40 | 40 | 0 2 | 2e+80 | 41 | 41 | 0 2 | 2e+81 | 41 | 41 | 0 2 | 2e+82 | 42 | 42 | 0 2 | 2e+83 | 42 | 42 | 0 2 | 2e+84 | 43 | 43 | 0 2 | 2e+85 | 43 | 43 | 0 2 | 2e+86 | 44 | 44 | 0 2 | 2e+87 | 44 | 44 | 0 2 | 2e+88 | 45 | 45 | 0 2 | 2e+89 | 45 | 45 | 0 2 | 2e+90 | 46 | 46 | 0 2 | 2e+91 | 46 | 46 | 0 2 | 2e+92 | 47 | 47 | 0 2 | 2e+93 | 47 | 47 | 0 2 | 2e+94 | 48 | 48 | 0 2 | 2e+95 | 48 | 48 | 0 2 | 2e+96 | 49 | 49 | 0 2 | 2e+97 | 49 | 49 | 0 2 | 2e+98 | 50 | 50 | 0 2 | 2e+99 | 50 | 50 | 0 2 | 2e+100 | 51 | 51 | 0 (201 rows) -- -- Comparison of sig_figs(sqrt(n)) for HEAD vs fix-sweight-v4 -- when DEC_DIGITS == 4 -- DEC_DIGITS | n | HEAD | fix-sweight-v4 | diff ------------+--------------+------+----------------+------ 4 | 2e-100 | 51 | 51 | 0 4 | 2e-99 | 50 | 50 | 0 4 | 2e-98 | 50 | 50 | 0 4 | 2e-97 | 49 | 49 | 0 4 | 2e-96 | 49 | 49 | 0 4 | 2e-95 | 48 | 48 | 0 4 | 2e-94 | 48 | 48 | 0 4 | 2e-93 | 47 | 47 | 0 4 | 2e-92 | 47 | 47 | 0 4 | 2e-91 | 46 | 46 | 0 4 | 2e-90 | 46 | 46 | 0 4 | 2e-89 | 45 | 45 | 0 4 | 2e-88 | 45 | 45 | 0 4 | 2e-87 | 44 | 44 | 0 4 | 2e-86 | 44 | 44 | 0 4 | 2e-85 | 43 | 43 | 0 4 | 2e-84 | 43 | 43 | 0 4 | 2e-83 | 42 | 42 | 0 4 | 2e-82 | 42 | 42 | 0 4 | 2e-81 | 41 | 41 | 0 4 | 2e-80 | 41 | 41 | 0 4 | 2e-79 | 40 | 40 | 0 4 | 2e-78 | 40 | 40 | 0 4 | 2e-77 | 39 | 39 | 0 4 | 2e-76 | 39 | 39 | 0 4 | 2e-75 | 38 | 38 | 0 4 | 2e-74 | 38 | 38 | 0 4 | 2e-73 | 37 | 37 | 0 4 | 2e-72 | 37 | 37 | 0 4 | 2e-71 | 36 | 36 | 0 4 | 2e-70 | 36 | 36 | 0 4 | 2e-69 | 35 | 35 | 0 4 | 2e-68 | 35 | 35 | 0 4 | 2e-67 | 34 | 34 | 0 4 | 2e-66 | 34 | 34 | 0 4 | 2e-65 | 33 | 33 | 0 4 | 2e-64 | 33 | 33 | 0 4 | 2e-63 | 32 | 32 | 0 4 | 2e-62 | 32 | 32 | 0 4 | 2e-61 | 31 | 31 | 0 4 | 2e-60 | 31 | 31 | 0 4 | 2e-59 | 30 | 30 | 0 4 | 2e-58 | 30 | 30 | 0 4 | 2e-57 | 29 | 29 | 0 4 | 2e-56 | 29 | 29 | 0 4 | 2e-55 | 28 | 28 | 0 4 | 2e-54 | 28 | 28 | 0 4 | 2e-53 | 27 | 27 | 0 4 | 2e-52 | 27 | 27 | 0 4 | 2e-51 | 26 | 26 | 0 4 | 2e-50 | 26 | 26 | 0 4 | 2e-49 | 25 | 25 | 0 4 | 2e-48 | 25 | 25 | 0 4 | 2e-47 | 24 | 24 | 0 4 | 2e-46 | 24 | 24 | 0 4 | 2e-45 | 23 | 23 | 0 4 | 2e-44 | 23 | 23 | 0 4 | 2e-43 | 22 | 22 | 0 4 | 2e-42 | 22 | 22 | 0 4 | 2e-41 | 21 | 21 | 0 4 | 2e-40 | 21 | 21 | 0 4 | 2e-39 | 20 | 20 | 0 4 | 2e-38 | 20 | 20 | 0 4 | 2e-37 | 19 | 19 | 0 4 | 2e-36 | 19 | 19 | 0 4 | 2e-35 | 18 | 18 | 0 4 | 2e-34 | 18 | 18 | 0 4 | 2e-33 | 17 | 17 | 0 4 | 2e-32 | 17 | 17 | 0 4 | 2e-31 | 16 | 16 | 0 4 | 2e-30 | 17 | 17 | 0 4 | 2e-29 | 17 | 17 | 0 4 | 2e-28 | 16 | 16 | 0 4 | 2e-27 | 16 | 16 | 0 4 | 2e-26 | 17 | 17 | 0 4 | 2e-25 | 17 | 17 | 0 4 | 2e-24 | 16 | 16 | 0 4 | 2e-23 | 16 | 16 | 0 4 | 2e-22 | 17 | 17 | 0 4 | 2e-21 | 17 | 17 | 0 4 | 2e-20 | 16 | 16 | 0 4 | 2e-19 | 16 | 16 | 0 4 | 2e-18 | 17 | 17 | 0 4 | 2e-17 | 17 | 17 | 0 4 | 2e-16 | 16 | 16 | 0 4 | 2e-15 | 16 | 16 | 0 4 | 2e-14 | 17 | 17 | 0 4 | 2e-13 | 17 | 17 | 0 4 | 2e-12 | 16 | 16 | 0 4 | 2e-11 | 16 | 16 | 0 4 | 0.0000000002 | 17 | 17 | 0 4 | 0.000000002 | 17 | 17 | 0 4 | 0.00000002 | 16 | 16 | 0 4 | 0.0000002 | 16 | 16 | 0 4 | 0.000002 | 17 | 17 | 0 4 | 0.00002 | 17 | 17 | 0 4 | 0.0002 | 16 | 16 | 0 4 | 0.002 | 16 | 16 | 0 4 | 0.02 | 17 | 17 | 0 4 | 0.2 | 17 | 17 | 0 4 | 2 | 16 | 16 | 0 4 | 20 | 16 | 16 | 0 4 | 200 | 17 | 17 | 0 4 | 2000 | 17 | 17 | 0 4 | 20000 | 16 | 16 | 0 4 | 200000 | 16 | 16 | 0 4 | 2000000 | 17 | 17 | 0 4 | 20000000 | 17 | 17 | 0 4 | 200000000 | 16 | 16 | 0 4 | 2000000000 | 16 | 16 | 0 4 | 20000000000 | 17 | 17 | 0 4 | 2e+11 | 17 | 17 | 0 4 | 2e+12 | 16 | 16 | 0 4 | 2e+13 | 16 | 16 | 0 4 | 2e+14 | 17 | 17 | 0 4 | 2e+15 | 17 | 17 | 0 4 | 2e+16 | 16 | 16 | 0 4 | 2e+17 | 16 | 16 | 0 4 | 2e+18 | 17 | 17 | 0 4 | 2e+19 | 17 | 17 | 0 4 | 2e+20 | 16 | 16 | 0 4 | 2e+21 | 16 | 16 | 0 4 | 2e+22 | 17 | 17 | 0 4 | 2e+23 | 17 | 17 | 0 4 | 2e+24 | 16 | 16 | 0 4 | 2e+25 | 16 | 16 | 0 4 | 2e+26 | 17 | 17 | 0 4 | 2e+27 | 17 | 17 | 0 4 | 2e+28 | 16 | 16 | 0 4 | 2e+29 | 16 | 16 | 0 4 | 2e+30 | 17 | 17 | 0 4 | 2e+31 | 17 | 17 | 0 4 | 2e+32 | 17 | 17 | 0 4 | 2e+33 | 17 | 17 | 0 4 | 2e+34 | 18 | 18 | 0 4 | 2e+35 | 18 | 18 | 0 4 | 2e+36 | 19 | 19 | 0 4 | 2e+37 | 19 | 19 | 0 4 | 2e+38 | 20 | 20 | 0 4 | 2e+39 | 20 | 20 | 0 4 | 2e+40 | 21 | 21 | 0 4 | 2e+41 | 21 | 21 | 0 4 | 2e+42 | 22 | 22 | 0 4 | 2e+43 | 22 | 22 | 0 4 | 2e+44 | 23 | 23 | 0 4 | 2e+45 | 23 | 23 | 0 4 | 2e+46 | 24 | 24 | 0 4 | 2e+47 | 24 | 24 | 0 4 | 2e+48 | 25 | 25 | 0 4 | 2e+49 | 25 | 25 | 0 4 | 2e+50 | 26 | 26 | 0 4 | 2e+51 | 26 | 26 | 0 4 | 2e+52 | 27 | 27 | 0 4 | 2e+53 | 27 | 27 | 0 4 | 2e+54 | 28 | 28 | 0 4 | 2e+55 | 28 | 28 | 0 4 | 2e+56 | 29 | 29 | 0 4 | 2e+57 | 29 | 29 | 0 4 | 2e+58 | 30 | 30 | 0 4 | 2e+59 | 30 | 30 | 0 4 | 2e+60 | 31 | 31 | 0 4 | 2e+61 | 31 | 31 | 0 4 | 2e+62 | 32 | 32 | 0 4 | 2e+63 | 32 | 32 | 0 4 | 2e+64 | 33 | 33 | 0 4 | 2e+65 | 33 | 33 | 0 4 | 2e+66 | 34 | 34 | 0 4 | 2e+67 | 34 | 34 | 0 4 | 2e+68 | 35 | 35 | 0 4 | 2e+69 | 35 | 35 | 0 4 | 2e+70 | 36 | 36 | 0 4 | 2e+71 | 36 | 36 | 0 4 | 2e+72 | 37 | 37 | 0 4 | 2e+73 | 37 | 37 | 0 4 | 2e+74 | 38 | 38 | 0 4 | 2e+75 | 38 | 38 | 0 4 | 2e+76 | 39 | 39 | 0 4 | 2e+77 | 39 | 39 | 0 4 | 2e+78 | 40 | 40 | 0 4 | 2e+79 | 40 | 40 | 0 4 | 2e+80 | 41 | 41 | 0 4 | 2e+81 | 41 | 41 | 0 4 | 2e+82 | 42 | 42 | 0 4 | 2e+83 | 42 | 42 | 0 4 | 2e+84 | 43 | 43 | 0 4 | 2e+85 | 43 | 43 | 0 4 | 2e+86 | 44 | 44 | 0 4 | 2e+87 | 44 | 44 | 0 4 | 2e+88 | 45 | 45 | 0 4 | 2e+89 | 45 | 45 | 0 4 | 2e+90 | 46 | 46 | 0 4 | 2e+91 | 46 | 46 | 0 4 | 2e+92 | 47 | 47 | 0 4 | 2e+93 | 47 | 47 | 0 4 | 2e+94 | 48 | 48 | 0 4 | 2e+95 | 48 | 48 | 0 4 | 2e+96 | 49 | 49 | 0 4 | 2e+97 | 49 | 49 | 0 4 | 2e+98 | 50 | 50 | 0 4 | 2e+99 | 50 | 50 | 0 4 | 2e+100 | 51 | 51 | 0 (201 rows) ^ permalink raw reply [nested|flat] 77+ messages in thread
end of thread, other threads:[~2023-01-31 21:59 UTC | newest] Thread overview: 77+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2020-01-10 06:08 [PATCH 4/4] CatCache expiration feature. Kyotaro Horiguchi <[email protected]> 2020-01-10 06:08 [PATCH v2 3/3] CatCache expiration feature. Kyotaro Horiguchi <[email protected]> 2020-01-10 06:08 [PATCH v3 3/3] CatCache expiration feature. Kyotaro Horiguchi <[email protected]> 2020-01-10 06:08 [PATCH v1 3/3] CatCache expiration feature. Kyotaro Horiguchi <[email protected]> 2020-11-06 08:27 [PATCH v5] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-06 08:27 [PATCH v4] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v5 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v7 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2020-11-18 07:54 [PATCH v6 1/3] CatCache expiration feature Kyotaro Horiguchi <[email protected]> 2021-01-27 11:08 [PATCH v9] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2021-01-27 11:08 [PATCH v8 1/1] CatCache expiration feature Heikki Linnakangas <[email protected]> 2023-01-29 13:33 Re: [PATCH] Fix old thinko in formula to compute sweight in numeric_sqrt(). Dean Rasheed <[email protected]> 2023-01-31 07:59 ` Re: [PATCH] Fix old thinko in formula to compute sweight in numeric_sqrt(). Joel Jacobson <[email protected]> 2023-01-31 13:40 ` Re: [PATCH] Fix old thinko in formula to compute sweight in numeric_sqrt(). Dean Rasheed <[email protected]> 2023-01-31 15:05 ` Re: [PATCH] Fix old thinko in formula to compute sweight in numeric_sqrt(). Joel Jacobson <[email protected]> 2023-01-31 19:25 ` Re: [PATCH] Fix old thinko in formula to compute sweight in numeric_sqrt(). Dean Rasheed <[email protected]> 2023-01-31 21:59 ` Re: [PATCH] Fix old thinko in formula to compute sweight in numeric_sqrt(). Joel Jacobson <[email protected]>
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