luciano/pg_ivm
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This commit fixes two issues

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1. Saves from race condition while doing table scan in object acess hook, which arises when the current drop object is pg_ivm_immv's toast table, which looks up for primary key which already got dropped earlier.
2. Use RangeVarGetRelidExtended(... AccessShareLock ...) instead of get_relname_relid().  That way, DROP EXTENSION can't cause errors in concurrent sessions that are in the middle of running the hook.
This commit is contained in:
ibhaskar2 2024-08-23 01:55:51 +05:30
parent 85b11c359a
commit d7d3977c2f
1 changed files with 16 additions and 19 deletions
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35
pg_ivm.c
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@ -25,6 +25,8 @@
#include "parser/parser.h"
#include "parser/scansup.h"
#include "tcop/tcopprot.h"
#include "nodes/makefuncs.h"
#include "utils/syscache.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
@ -36,8 +38,6 @@
PG_MODULE_MAGIC;
static Oid pg_ivm_immv_id = InvalidOid;
static Oid pg_ivm_immv_pkey_id = InvalidOid;
static object_access_hook_type PrevObjectAccessHook = NULL;
@ -326,10 +326,9 @@ CreateChangePreventTrigger(Oid matviewOid)
Oid
PgIvmImmvRelationId(void)
{
if (!OidIsValid(pg_ivm_immv_id))
pg_ivm_immv_id = get_relname_relid("pg_ivm_immv", PG_CATALOG_NAMESPACE);
return pg_ivm_immv_id;
return RangeVarGetRelidExtended(
makeRangeVar("pg_catalog", "pg_ivm_immv", -1),
AccessShareLock, RVR_MISSING_OK, NULL, NULL);
}
/*
@ -338,10 +337,9 @@ PgIvmImmvRelationId(void)
Oid
PgIvmImmvPrimaryKeyIndexId(void)
{
if (!OidIsValid(pg_ivm_immv_pkey_id))
pg_ivm_immv_pkey_id = get_relname_relid("pg_ivm_immv_pkey", PG_CATALOG_NAMESPACE);
return pg_ivm_immv_pkey_id;
return RangeVarGetRelidExtended(
makeRangeVar("pg_catalog", "pg_ivm_immv_pkey", -1),
AccessShareLock, RVR_MISSING_OK, NULL, NULL);
}
/*
@ -391,24 +389,23 @@ PgIvmObjectAccessHook(ObjectAccessType access, Oid classId,
HeapTuple tup;
Oid pgIvmImmvOid = PgIvmImmvRelationId();
/* pg_ivm_immv is not created yet, so there are no IMMVs, either. */
if (pgIvmImmvOid == InvalidOid)
return;
Oid pgIvmImmvPkOid = PgIvmImmvPrimaryKeyIndexId();
/*
* When the dropped table is pg_ivm_immv, we don't need to continue
* any more. Also, in this case, the index on it is already dropped,
* so the index scan below will fail and raise an error.
* Index or table not yet created (so no IMMVs yet), already dropped
* (expect IMMVs also gone soon), or renamed. It's not great that a
* rename of either object will silently break IMMVs, but that's
* better than ERROR below.
*/
if (objectId == pgIvmImmvOid)
return;
if (pgIvmImmvPkOid == InvalidOid || pgIvmImmvOid == InvalidOid)
return;
pgIvmImmv = table_open(pgIvmImmvOid, AccessShareLock);
ScanKeyInit(&key,
Anum_pg_ivm_immv_immvrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(objectId));
scan = systable_beginscan(pgIvmImmv, PgIvmImmvPrimaryKeyIndexId(),
scan = systable_beginscan(pgIvmImmv, pgIvmImmvPkOid,
true, NULL, 1, &key);
tup = systable_getnext(scan);