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Use object_access_hook to drop an IMMV entry from pg_ivm_immv (#29)

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Previously, we used an event trigger and executed DELETE command,
but it caused a privilege error when non-superuser dropped a table
even if it is irrelevant to IMMV.

To fix it, we now use object_access_hook and an entry is deleted
via CatalogTupleDelete which doesn't need the superuser privilege.

Issue #25
This commit is contained in:
Yugo Nagata 2022-09-30 23:49:51 +09:00 committed by GitHub
parent 1d21409321
commit e31dc21eaa
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2 changed files with 51 additions and 0 deletions
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5
pg_ivm--1.2--1.3.sql
View file

@ -11,3 +11,8 @@ RETURNS text
STRICT
AS 'MODULE_PATHNAME', 'get_immv_def'
LANGUAGE C;
-- event trigger
DROP EVENT TRIGGER pg_ivm_sql_drop_trigger;
DROP FUNCTION pg_ivm_sql_drop_trigger_func;

46
pg_ivm.c
View file

@ -11,10 +11,13 @@
*/
#include "postgres.h"
#include "access/genam.h"
#include "access/table.h"
#include "access/xact.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_namespace_d.h"
#include "catalog/pg_trigger_d.h"
#include "commands/trigger.h"
@ -23,6 +26,7 @@
#include "parser/scansup.h"
#include "tcop/tcopprot.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/regproc.h"
#include "utils/rel.h"
@ -35,6 +39,8 @@ 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;
void _PG_init(void);
static void IvmXactCallback(XactEvent event, void *arg);
@ -42,6 +48,9 @@ static void IvmSubXactCallback(SubXactEvent event, SubTransactionId mySubid,
SubTransactionId parentSubid, void *arg);
static void parseNameAndColumns(const char *string, List **names, List **colNames);
static void PgIvmObjectAccessHook(ObjectAccessType access, Oid classId,
Oid objectId, int subId, void *arg);
/* SQL callable functions */
PG_FUNCTION_INFO_V1(create_immv);
PG_FUNCTION_INFO_V1(refresh_immv);
@ -75,6 +84,9 @@ _PG_init(void)
{
RegisterXactCallback(IvmXactCallback, NULL);
RegisterSubXactCallback(IvmSubXactCallback, NULL);
PrevObjectAccessHook = object_access_hook;
object_access_hook = PgIvmObjectAccessHook;
}
/*
@ -350,3 +362,37 @@ get_immv_def(PG_FUNCTION_ARGS)
table_close(matviewRel, NoLock);
PG_RETURN_TEXT_P(cstring_to_text(querystring));
}
/*
* object_access_hook function for dropping an IMMV
*/
static void
PgIvmObjectAccessHook(ObjectAccessType access, Oid classId,
Oid objectId, int subId, void *arg)
{
if (PrevObjectAccessHook)
PrevObjectAccessHook(access, classId, objectId, subId, arg);
if (access == OAT_DROP && classId == RelationRelationId && !OidIsValid(subId))
{
Relation pgIvmImmv = table_open(PgIvmImmvRelationId(), AccessShareLock);
SysScanDesc scan;
ScanKeyData key;
HeapTuple tup;
ScanKeyInit(&key,
Anum_pg_ivm_immv_immvrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(objectId));
scan = systable_beginscan(pgIvmImmv, PgIvmImmvPrimaryKeyIndexId(),
true, NULL, 1, &key);
tup = systable_getnext(scan);
if (HeapTupleIsValid(tup))
CatalogTupleDelete(pgIvmImmv, &tup->t_self);
systable_endscan(scan);
table_close(pgIvmImmv, NoLock);
}
}