@ -7,7 +7,7 @@
* Portions Copyright ( c ) 1994 , Regents of the University of California
*
* IDENTIFICATION
* $ Header : / cvsroot / pgsql / src / backend / commands / trigger . c , v 1.113 2002 / 04 / 12 20 : 38 : 24 tgl Exp $
* $ Header : / cvsroot / pgsql / src / backend / commands / trigger . c , v 1.114 2002 / 04 / 19 16 : 36 : 08 tgl Exp $
*
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
*/
@ -90,14 +90,15 @@ CreateTrigger(CreateTrigStmt *stmt)
elog ( ERROR , " permission denied " ) ;
/*
* If trigger is a constraint , user trigger name as constraint name
* If trigger is an RI constraint , use trigger name as constraint name
* and build a unique trigger name instead .
*/
if ( stmt - > isconstraint )
{
constrname = stmt - > trigname ;
snprintf ( constrtrigname , sizeof ( constrtrigname ) ,
" RI_ConstraintTrigger_%u " , newoid ( ) ) ;
stmt - > trigname = constrtrigname ;
sprintf ( constrtrigname , " RI_ConstraintTrigger_%u " , newoid ( ) ) ;
if ( stmt - > constrrel ! = NULL )
constrrelid = RangeVarGetRelid ( stmt - > constrrel , false ) ;
@ -139,15 +140,20 @@ CreateTrigger(CreateTrigStmt *stmt)
}
/*
* Scan pg_trigger for existing triggers on relation . NOTE that this
* is cool only because we have AccessExclusiveLock on the relation ,
* so the trigger set won ' t be changing underneath us .
* Scan pg_trigger for existing triggers on relation . We do this mainly
* because we must count them ; a secondary benefit is to give a nice
* error message if there ' s already a trigger of the same name . ( The
* unique index on tgrelid / tgname would complain anyway . )
*
* NOTE that this is cool only because we have AccessExclusiveLock on the
* relation , so the trigger set won ' t be changing underneath us .
*/
tgrel = heap_openr ( TriggerRelationName , RowExclusiveLock ) ;
ScanKeyEntryInitialize ( & key , 0 , Anum_pg_trigger_tgrelid ,
ScanKeyEntryInitialize ( & key , 0 ,
Anum_pg_trigger_tgrelid ,
F_OIDEQ ,
ObjectIdGetDatum ( RelationGetRelid ( rel ) ) ) ;
tgscan = systable_beginscan ( tgrel , TriggerRelidIndex , true ,
tgscan = systable_beginscan ( tgrel , TriggerRelidName Index , true ,
SnapshotNow , 1 , & key ) ;
while ( HeapTupleIsValid ( tuple = systable_getnext ( tgscan ) ) )
{
@ -336,15 +342,20 @@ DropTrigger(Oid relid, const char *trigname)
/*
* Search pg_trigger , delete target trigger , count remaining triggers
* for relation . Note this is OK only because we have
* AccessExclusiveLock on the rel , so no one else is creating / deleting
* triggers on this rel at the same time .
* for relation . ( Although we could fetch and delete the target
* trigger directly , we ' d still have to scan the remaining triggers ,
* so we may as well do both in one indexscan . )
*
* Note this is OK only because we have AccessExclusiveLock on the rel ,
* so no one else is creating / deleting triggers on this rel at the same
* time .
*/
tgrel = heap_openr ( TriggerRelationName , RowExclusiveLock ) ;
ScanKeyEntryInitialize ( & key , 0 , Anum_pg_trigger_tgrelid ,
ScanKeyEntryInitialize ( & key , 0 ,
Anum_pg_trigger_tgrelid ,
F_OIDEQ ,
ObjectIdGetDatum ( relid ) ) ;
tgscan = systable_beginscan ( tgrel , TriggerRelidIndex , true ,
tgscan = systable_beginscan ( tgrel , TriggerRelidName Index , true ,
SnapshotNow , 1 , & key ) ;
while ( HeapTupleIsValid ( tuple = systable_getnext ( tgscan ) ) )
{
@ -409,10 +420,11 @@ RelationRemoveTriggers(Relation rel)
bool found = false ;
tgrel = heap_openr ( TriggerRelationName , RowExclusiveLock ) ;
ScanKeyEntryInitialize ( & key , 0 , Anum_pg_trigger_tgrelid ,
ScanKeyEntryInitialize ( & key , 0 ,
Anum_pg_trigger_tgrelid ,
F_OIDEQ ,
ObjectIdGetDatum ( RelationGetRelid ( rel ) ) ) ;
tgscan = systable_beginscan ( tgrel , TriggerRelidIndex , true ,
tgscan = systable_beginscan ( tgrel , TriggerRelidName Index , true ,
SnapshotNow , 1 , & key ) ;
while ( HeapTupleIsValid ( tup = systable_getnext ( tgscan ) ) )
@ -462,7 +474,8 @@ RelationRemoveTriggers(Relation rel)
/*
* Also drop all constraint triggers referencing this relation
*/
ScanKeyEntryInitialize ( & key , 0 , Anum_pg_trigger_tgconstrrelid ,
ScanKeyEntryInitialize ( & key , 0 ,
Anum_pg_trigger_tgconstrrelid ,
F_OIDEQ ,
ObjectIdGetDatum ( RelationGetRelid ( rel ) ) ) ;
tgscan = systable_beginscan ( tgrel , TriggerConstrRelidIndex , true ,
@ -502,7 +515,7 @@ RelationBuildTriggers(Relation relation)
{
TriggerDesc * trigdesc ;
int ntrigs = relation - > rd_rel - > reltriggers ;
Trigger * triggers = NULL ;
Trigger * triggers ;
int found = 0 ;
Relation tgrel ;
ScanKeyData skey ;
@ -511,6 +524,15 @@ RelationBuildTriggers(Relation relation)
struct varlena * val ;
bool isnull ;
triggers = ( Trigger * ) MemoryContextAlloc ( CacheMemoryContext ,
ntrigs * sizeof ( Trigger ) ) ;
/*
* Note : since we scan the triggers using TriggerRelidNameIndex ,
* we will be reading the triggers in name order , except possibly
* during emergency - recovery operations ( ie , IsIgnoringSystemIndexes ) .
* This in turn ensures that triggers will be fired in name order .
*/
ScanKeyEntryInitialize ( & skey ,
( bits16 ) 0x0 ,
( AttrNumber ) Anum_pg_trigger_tgrelid ,
@ -518,7 +540,7 @@ RelationBuildTriggers(Relation relation)
ObjectIdGetDatum ( RelationGetRelid ( relation ) ) ) ;
tgrel = heap_openr ( TriggerRelationName , AccessShareLock ) ;
tgscan = systable_beginscan ( tgrel , TriggerRelidIndex , true ,
tgscan = systable_beginscan ( tgrel , TriggerRelidName Index , true ,
SnapshotNow , 1 , & skey ) ;
while ( HeapTupleIsValid ( htup = systable_getnext ( tgscan ) ) )
@ -526,16 +548,9 @@ RelationBuildTriggers(Relation relation)
Form_pg_trigger pg_trigger = ( Form_pg_trigger ) GETSTRUCT ( htup ) ;
Trigger * build ;
if ( found = = ntrigs )
if ( found > = ntrigs )
elog ( ERROR , " RelationBuildTriggers: unexpected record found for rel %s " ,
RelationGetRelationName ( relation ) ) ;
if ( triggers = = NULL )
triggers = ( Trigger * ) MemoryContextAlloc ( CacheMemoryContext ,
sizeof ( Trigger ) ) ;
else
triggers = ( Trigger * ) repalloc ( triggers ,
( found + 1 ) * sizeof ( Trigger ) ) ;
build = & ( triggers [ found ] ) ;
build - > tgoid = htup - > t_data - > t_oid ;
@ -730,6 +745,9 @@ equalTriggerDescs(TriggerDesc *trigdesc1, TriggerDesc *trigdesc2)
* We need not examine the " index " data , just the trigger array
* itself ; if we have the same triggers with the same types , the
* derived index data should match .
*
* As of 7.3 we assume trigger set ordering is significant in the
* comparison ; so we just compare corresponding slots of the two sets .
*/
if ( trigdesc1 ! = NULL )
{
@ -740,21 +758,9 @@ equalTriggerDescs(TriggerDesc *trigdesc1, TriggerDesc *trigdesc2)
for ( i = 0 ; i < trigdesc1 - > numtriggers ; i + + )
{
Trigger * trig1 = trigdesc1 - > triggers + i ;
Trigger * trig2 = NULL ;
Trigger * trig2 = trigdesc2 - > triggers + i ;
/*
* We can ' t assume that the triggers are always read from
* pg_trigger in the same order ; so use the trigger OIDs to
* identify the triggers to compare . ( We assume here that the
* same OID won ' t appear twice in either trigger set . )
*/
for ( j = 0 ; j < trigdesc2 - > numtriggers ; j + + )
{
trig2 = trigdesc2 - > triggers + j ;
if ( trig1 - > tgoid = = trig2 - > tgoid )
break ;
}
if ( j > = trigdesc2 - > numtriggers )
if ( trig1 - > tgoid ! = trig2 - > tgoid )
return false ;
if ( strcmp ( trig1 - > tgname , trig2 - > tgname ) ! = 0 )
return false ;
Tom Lane
24 years ago