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Revert: Avoid looping over all type cache entries in TypeCacheRelCallback()

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This commit reverts c14d4acb8 as the patch design didn't take into account
that TypeCacheEntry could be invalidated during the lookup_type_cache() call.

Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/1927cba4-177e-5c23-cbcc-d444a850304f%40gmail.com
This commit is contained in:
Alexander Korotkov 2024-08-26 00:22:44 +03:00
parent c14d4acb81
commit 8daa62a10c
2 changed files with 44 additions and 232 deletions
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275
src/backend/utils/cache/typcache.c vendored
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@ -77,20 +77,6 @@
/* The main type cache hashtable searched by lookup_type_cache */
static HTAB *TypeCacheHash = NULL;
/*
* The mapping of relation's OID to the corresponding composite type OID.
* We're keeping the map entry when the corresponding typentry has something
* to clear i.e it has either TCFLAGS_HAVE_PG_TYPE_DATA, or
* TCFLAGS_OPERATOR_FLAGS, or tupdesc.
*/
static HTAB *RelIdToTypeIdCacheHash = NULL;
typedef struct RelIdToTypeIdCacheEntry
{
Oid relid; /* OID of the relation */
Oid composite_typid; /* OID of the relation's composite type */
} RelIdToTypeIdCacheEntry;
/* List of type cache entries for domain types */
static TypeCacheEntry *firstDomainTypeEntry = NULL;
@ -343,8 +329,6 @@ static void shared_record_typmod_registry_detach(dsm_segment *segment,
static TupleDesc find_or_make_matching_shared_tupledesc(TupleDesc tupdesc);
static dsa_pointer share_tupledesc(dsa_area *area, TupleDesc tupdesc,
uint32 typmod);
static void insert_rel_type_cache_if_needed(TypeCacheEntry *typentry);
static void delete_rel_type_cache_if_needed(TypeCacheEntry *typentry);
/*
@ -392,13 +376,6 @@ lookup_type_cache(Oid type_id, int flags)
TypeCacheHash = hash_create("Type information cache", 64,
&ctl, HASH_ELEM | HASH_FUNCTION);
Assert(RelIdToTypeIdCacheHash == NULL);
ctl.keysize = sizeof(Oid);
ctl.entrysize = sizeof(RelIdToTypeIdCacheEntry);
RelIdToTypeIdCacheHash = hash_create("Map from relid to OID of cached composite type", 64,
&ctl, HASH_ELEM | HASH_BLOBS);
/* Also set up callbacks for SI invalidations */
CacheRegisterRelcacheCallback(TypeCacheRelCallback, (Datum) 0);
CacheRegisterSyscacheCallback(TYPEOID, TypeCacheTypCallback, (Datum) 0);
@ -410,8 +387,6 @@ lookup_type_cache(Oid type_id, int flags)
CreateCacheMemoryContext();
}
Assert(TypeCacheHash != NULL && RelIdToTypeIdCacheHash != NULL);
/* Try to look up an existing entry */
typentry = (TypeCacheEntry *) hash_search(TypeCacheHash,
&type_id,
@ -463,7 +438,6 @@ lookup_type_cache(Oid type_id, int flags)
typentry->typelem = typtup->typelem;
typentry->typcollation = typtup->typcollation;
typentry->flags |= TCFLAGS_HAVE_PG_TYPE_DATA;
insert_rel_type_cache_if_needed(typentry);
/* If it's a domain, immediately thread it into the domain cache list */
if (typentry->typtype == TYPTYPE_DOMAIN)
@ -509,7 +483,6 @@ lookup_type_cache(Oid type_id, int flags)
typentry->typelem = typtup->typelem;
typentry->typcollation = typtup->typcollation;
typentry->flags |= TCFLAGS_HAVE_PG_TYPE_DATA;
insert_rel_type_cache_if_needed(typentry);
ReleaseSysCache(tp);
}
@ -2308,53 +2281,6 @@ SharedRecordTypmodRegistryAttach(SharedRecordTypmodRegistry *registry)
CurrentSession->shared_typmod_table = typmod_table;
}
/*
* InvalidateCompositeTypeCacheEntry
* Invalidate particular TypeCacheEntry on Relcache inval callback
*
* Delete the cached tuple descriptor (if any) for the given composite
* type, and reset whatever info we have cached about the composite type's
* comparability.
*/
static void
InvalidateCompositeTypeCacheEntry(TypeCacheEntry *typentry)
{
bool hadTupDescOrOpclass;
Assert(typentry->typtype == TYPTYPE_COMPOSITE &&
OidIsValid(typentry->typrelid));
hadTupDescOrOpclass = (typentry->tupDesc != NULL) ||
(typentry->flags & TCFLAGS_OPERATOR_FLAGS);
/* Delete tupdesc if we have it */
if (typentry->tupDesc != NULL)
{
/*
* Release our refcount and free the tupdesc if none remain. We can't
* use DecrTupleDescRefCount here because this reference is not logged
* by the current resource owner.
*/
Assert(typentry->tupDesc->tdrefcount > 0);
if (--typentry->tupDesc->tdrefcount == 0)
FreeTupleDesc(typentry->tupDesc);
typentry->tupDesc = NULL;
/*
* Also clear tupDesc_identifier, so that anyone watching it will
* realize that the tupdesc has changed.
*/
typentry->tupDesc_identifier = 0;
}
/* Reset equality/comparison/hashing validity information */
typentry->flags &= ~TCFLAGS_OPERATOR_FLAGS;
/* Call check_delete_rel_type_cache() if we actually cleared something */
if (hadTupDescOrOpclass)
delete_rel_type_cache_if_needed(typentry);
}
/*
* TypeCacheRelCallback
* Relcache inval callback function
@ -2364,55 +2290,63 @@ InvalidateCompositeTypeCacheEntry(TypeCacheEntry *typentry)
* whatever info we have cached about the composite type's comparability.
*
* This is called when a relcache invalidation event occurs for the given
* relid. We can't use syscache to find a type corresponding to the given
* relation because the code can be called outside of transaction. Thus we use
* the RelIdToTypeIdCacheHash map to locate appropriate typcache entry.
* relid. We must scan the whole typcache hash since we don't know the
* type OID corresponding to the relid. We could do a direct search if this
* were a syscache-flush callback on pg_type, but then we would need all
* ALTER-TABLE-like commands that could modify a rowtype to issue syscache
* invals against the rel's pg_type OID. The extra SI signaling could very
* well cost more than we'd save, since in most usages there are not very
* many entries in a backend's typcache. The risk of bugs-of-omission seems
* high, too.
*
* Another possibility, with only localized impact, is to maintain a second
* hashtable that indexes composite-type typcache entries by their typrelid.
* But it's still not clear it's worth the trouble.
*/
static void
TypeCacheRelCallback(Datum arg, Oid relid)
{
HASH_SEQ_STATUS status;
TypeCacheEntry *typentry;
/*
* RelIdToTypeIdCacheHash and TypeCacheHash should exist, otherwise this
* callback wouldn't be registered
*/
if (OidIsValid(relid))
/* TypeCacheHash must exist, else this callback wouldn't be registered */
hash_seq_init(&status, TypeCacheHash);
while ((typentry = (TypeCacheEntry *) hash_seq_search(&status)) != NULL)
{
RelIdToTypeIdCacheEntry *relentry;
/*
* Find an RelIdToTypeIdCacheHash entry, which should exist as soon as
* corresponding typcache entry has something to clean.
*/
relentry = (RelIdToTypeIdCacheEntry *) hash_search(RelIdToTypeIdCacheHash,
&relid,
HASH_FIND, NULL);
if (relentry != NULL)
if (typentry->typtype == TYPTYPE_COMPOSITE)
{
typentry = (TypeCacheEntry *) hash_search(TypeCacheHash,
&relentry->composite_typid,
HASH_FIND, NULL);
/* Skip if no match, unless we're zapping all composite types */
if (relid != typentry->typrelid && relid != InvalidOid)
continue;
if (typentry != NULL)
/* Delete tupdesc if we have it */
if (typentry->tupDesc != NULL)
{
Assert(typentry->typtype == TYPTYPE_COMPOSITE);
Assert(relid == typentry->typrelid);
/*
* Release our refcount, and free the tupdesc if none remain.
* (Can't use DecrTupleDescRefCount because this reference is
* not logged in current resource owner.)
*/
Assert(typentry->tupDesc->tdrefcount > 0);
if (--typentry->tupDesc->tdrefcount == 0)
FreeTupleDesc(typentry->tupDesc);
typentry->tupDesc = NULL;
InvalidateCompositeTypeCacheEntry(typentry);
/*
* Also clear tupDesc_identifier, so that anything watching
* that will realize that the tupdesc has possibly changed.
* (Alternatively, we could specify that to detect possible
* tupdesc change, one must check for tupDesc != NULL as well
* as tupDesc_identifier being the same as what was previously
* seen. That seems error-prone.)
*/
typentry->tupDesc_identifier = 0;
}
}
/*
* Visit all the domain types sequentially. Typically this shouldn't
* affect performance since domain types are less tended to bloat.
* Domain types are created manually, unlike composite types which are
* automatically created for every temporary table.
*/
for (typentry = firstDomainTypeEntry;
typentry != NULL;
typentry = typentry->nextDomain)
/* Reset equality/comparison/hashing validity information */
typentry->flags &= ~TCFLAGS_OPERATOR_FLAGS;
}
else if (typentry->typtype == TYPTYPE_DOMAIN)
{
/*
* If it's domain over composite, reset flags. (We don't bother
@ -2424,36 +2358,6 @@ TypeCacheRelCallback(Datum arg, Oid relid)
typentry->flags &= ~TCFLAGS_OPERATOR_FLAGS;
}
}
else
{
HASH_SEQ_STATUS status;
/*
* Relid is invalid. By convention we need to reset all composite
* types in cache. Also, we should reset flags for domain types, and
* we loop over all entries in hash, so, do it in a single scan.
*/
hash_seq_init(&status, TypeCacheHash);
while ((typentry = (TypeCacheEntry *) hash_seq_search(&status)) != NULL)
{
if (typentry->typtype == TYPTYPE_COMPOSITE)
{
InvalidateCompositeTypeCacheEntry(typentry);
}
else if (typentry->typtype == TYPTYPE_DOMAIN)
{
/*
* If it's domain over composite, reset flags. (We don't
* bother trying to determine whether the specific base type
* needs a reset.) Note that if we haven't determined whether
* the base type is composite, we don't need to reset
* anything.
*/
if (typentry->flags & TCFLAGS_DOMAIN_BASE_IS_COMPOSITE)
typentry->flags &= ~TCFLAGS_OPERATOR_FLAGS;
}
}
}
}
/*
@ -2484,8 +2388,6 @@ TypeCacheTypCallback(Datum arg, int cacheid, uint32 hashvalue)
while ((typentry = (TypeCacheEntry *) hash_seq_search(&status)) != NULL)
{
bool hadPgTypeData = (typentry->flags & TCFLAGS_HAVE_PG_TYPE_DATA);
Assert(hashvalue == 0 || typentry->type_id_hash == hashvalue);
/*
@ -2495,13 +2397,6 @@ TypeCacheTypCallback(Datum arg, int cacheid, uint32 hashvalue)
*/
typentry->flags &= ~(TCFLAGS_HAVE_PG_TYPE_DATA |
TCFLAGS_CHECKED_DOMAIN_CONSTRAINTS);
/*
* Call check_delete_rel_type_cache() if we cleaned
* TCFLAGS_HAVE_PG_TYPE_DATA flag previously.
*/
if (hadPgTypeData)
delete_rel_type_cache_if_needed(typentry);
}
}
@ -3010,85 +2905,3 @@ shared_record_typmod_registry_detach(dsm_segment *segment, Datum datum)
}
CurrentSession->shared_typmod_registry = NULL;
}
/*
* Insert RelIdToTypeIdCacheHash entry after setting of the
* TCFLAGS_HAVE_PG_TYPE_DATA flag if needed.
*/
static void
insert_rel_type_cache_if_needed(TypeCacheEntry *typentry)
{
Assert(typentry->flags & TCFLAGS_HAVE_PG_TYPE_DATA);
/* Immediately quit for non-composite types */
if (typentry->typtype != TYPTYPE_COMPOSITE)
return;
/* typrelid should be given for composite types */
Assert(OidIsValid(typentry->typrelid));
/*
* Insert a RelIdToTypeIdCacheHash entry if the typentry doesn't have any
* information indicating there should be such an entry already.
*/
if (!(typentry->flags & TCFLAGS_OPERATOR_FLAGS) &&
typentry->tupDesc == NULL)
{
RelIdToTypeIdCacheEntry *relentry;
bool found;
relentry = (RelIdToTypeIdCacheEntry *) hash_search(RelIdToTypeIdCacheHash,
&typentry->typrelid,
HASH_ENTER, &found);
Assert(!found);
relentry->relid = typentry->typrelid;
relentry->composite_typid = typentry->type_id;
}
}
/*
* Delete entry RelIdToTypeIdCacheHash if needed after resetting of the
* TCFLAGS_HAVE_PG_TYPE_DATA flag, or any of TCFLAGS_OPERATOR_FLAGS flags,
* or tupDesc.
*/
static void
delete_rel_type_cache_if_needed(TypeCacheEntry *typentry)
{
/* Immediately quit for non-composite types */
if (typentry->typtype != TYPTYPE_COMPOSITE)
return;
/* typrelid should be given for composite types */
Assert(OidIsValid(typentry->typrelid));
/*
* Delete a RelIdToTypeIdCacheHash entry if the typentry doesn't have any
* information indicating entry should be still there.
*/
if (!(typentry->flags & TCFLAGS_HAVE_PG_TYPE_DATA) &&
!(typentry->flags & TCFLAGS_OPERATOR_FLAGS) &&
typentry->tupDesc == NULL)
{
bool found;
(void) hash_search(RelIdToTypeIdCacheHash,
&typentry->typrelid,
HASH_REMOVE, &found);
Assert(found);
}
else
{
#ifdef USE_ASSERT_CHECKING
/*
* In assert-enabled builds otherwise check for RelIdToTypeIdCacheHash
* entry if it should exist.
*/
bool found;
(void) hash_search(RelIdToTypeIdCacheHash,
&typentry->typrelid,
HASH_FIND, &found);
Assert(found);
#endif
}
}

1
src/tools/pgindent/typedefs.list
View File

@ -2377,7 +2377,6 @@ RelFileLocator
RelFileLocatorBackend
RelFileNumber
RelIdCacheEnt
RelIdToTypeIdCacheEntry
RelInfo
RelInfoArr
RelMapFile