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pg_trigger's index on tgrelid is replaced by a unique index on

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(tgrelid, tgname).  This provides an additional check on trigger name
uniqueness per-table (which was already enforced by the code anyway).
With this change, RelationBuildTriggers will read the triggers in
order by tgname, since it's scanning using this index.  Since a
predictable trigger ordering has been requested for some time, document
this behavior as a feature.  Also document that rules fire in name
order, since yesterday's changes to pg_rewrite indexing cause that too.
This commit is contained in:
Tom Lane
2002-04-19 16:36:08 +00:00
parent 87d00363cb
commit 201737168c
11 changed files with 230 additions and 172 deletions
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4
src/backend/catalog/indexing.c
View File

@@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/catalog/indexing.c,v 1.91 2002/04/18 20:01:09 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/catalog/indexing.c,v 1.92 2002/04/19 16:36:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -74,7 +74,7 @@ char *Name_pg_shadow_indices[Num_pg_shadow_indices] =
char *Name_pg_statistic_indices[Num_pg_statistic_indices] =
{StatisticRelidAttnumIndex};
char *Name_pg_trigger_indices[Num_pg_trigger_indices] =
{TriggerRelidIndex, TriggerConstrNameIndex, TriggerConstrRelidIndex, TriggerOidIndex};
{TriggerRelidNameIndex, TriggerConstrNameIndex, TriggerConstrRelidIndex, TriggerOidIndex};
char *Name_pg_type_indices[Num_pg_type_indices] =
{TypeNameNspIndex, TypeOidIndex};
char *Name_pg_description_indices[Num_pg_description_indices] =

23
src/backend/commands/comment.c
View File

@@ -7,7 +7,7 @@
* Copyright (c) 1999-2001, PostgreSQL Global Development Group
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/comment.c,v 1.42 2002/04/18 20:01:09 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/comment.c,v 1.43 2002/04/19 16:36:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -753,7 +753,7 @@ CommentTrigger(List *qualname, char *comment)
Relation pg_trigger,
relation;
HeapTuple triggertuple;
HeapScanDesc scan;
SysScanDesc scan;
ScanKeyData entry[2];
Oid oid;
@@ -774,17 +774,22 @@ CommentTrigger(List *qualname, char *comment)
elog(ERROR, "you are not permitted to comment on trigger '%s' for relation '%s'",
trigname, RelationGetRelationName(relation));
/* Fetch the trigger oid from pg_trigger */
/*
* Fetch the trigger tuple from pg_trigger. There can be only one
* because of the unique index.
*/
pg_trigger = heap_openr(TriggerRelationName, AccessShareLock);
ScanKeyEntryInitialize(&entry[0], 0x0, Anum_pg_trigger_tgrelid,
ScanKeyEntryInitialize(&entry[0], 0x0,
Anum_pg_trigger_tgrelid,
F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
ScanKeyEntryInitialize(&entry[1], 0x0, Anum_pg_trigger_tgname,
ScanKeyEntryInitialize(&entry[1], 0x0,
Anum_pg_trigger_tgname,
F_NAMEEQ,
CStringGetDatum(trigname));
scan = heap_beginscan(pg_trigger, 0, SnapshotNow, 2, entry);
triggertuple = heap_getnext(scan, 0);
scan = systable_beginscan(pg_trigger, TriggerRelidNameIndex, true,
SnapshotNow, 2, entry);
triggertuple = systable_getnext(scan);
/* If no trigger exists for the relation specified, notify user */
@@ -794,7 +799,7 @@ CommentTrigger(List *qualname, char *comment)
oid = triggertuple->t_data->t_oid;
heap_endscan(scan);
systable_endscan(scan);
/* Create the comments with the pg_trigger oid */

6
src/backend/commands/tablecmds.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.3 2002/04/18 20:01:09 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.4 2002/04/19 16:36:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -2909,10 +2909,10 @@ update_ri_trigger_args(Oid relid,
if (fk_scan)
irel = index_openr(TriggerConstrRelidIndex);
else
irel = index_openr(TriggerRelidIndex);
irel = index_openr(TriggerRelidNameIndex);
ScanKeyEntryInitialize(&skey[0], 0x0,
1, /* always column 1 of index */
1, /* column 1 of index in either case */
F_OIDEQ,
ObjectIdGetDatum(relid));
idxtgscan = index_beginscan(irel, false, 1, skey);

86
src/backend/commands/trigger.c
View File

@@ -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, TriggerRelidNameIndex, 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, TriggerRelidNameIndex, 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, TriggerRelidNameIndex, 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, TriggerRelidNameIndex, 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;

74
src/backend/utils/cache/relcache.c vendored
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.161 2002/04/18 20:01:09 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.162 2002/04/19 16:36:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -635,10 +635,10 @@ RelationBuildRuleLock(Relation relation)
{
MemoryContext rulescxt;
MemoryContext oldcxt;
HeapTuple pg_rewrite_tuple;
Relation pg_rewrite_desc;
TupleDesc pg_rewrite_tupdesc;
SysScanDesc pg_rewrite_scan;
HeapTuple rewrite_tuple;
Relation rewrite_desc;
TupleDesc rewrite_tupdesc;
SysScanDesc rewrite_scan;
ScanKeyData key;
RuleLock *rulelock;
int numlocks;
@@ -657,7 +657,7 @@ RelationBuildRuleLock(Relation relation)
relation->rd_rulescxt = rulescxt;
/*
* form an array to hold the rewrite rules (the array is extended if
* allocate an array to hold the rewrite rules (the array is extended if
* necessary)
*/
maxlocks = 4;
@@ -675,18 +675,22 @@ RelationBuildRuleLock(Relation relation)
/*
* open pg_rewrite and begin a scan
*
* Note: since we scan the rules using RewriteRelRulenameIndex,
* we will be reading the rules in name order, except possibly
* during emergency-recovery operations (ie, IsIgnoringSystemIndexes).
* This in turn ensures that rules will be fired in name order.
*/
pg_rewrite_desc = heap_openr(RewriteRelationName, AccessShareLock);
pg_rewrite_tupdesc = RelationGetDescr(pg_rewrite_desc);
pg_rewrite_scan = systable_beginscan(pg_rewrite_desc,
RewriteRelRulenameIndex,
criticalRelcachesBuilt,
SnapshotNow,
1, &key);
rewrite_desc = heap_openr(RewriteRelationName, AccessShareLock);
rewrite_tupdesc = RelationGetDescr(rewrite_desc);
rewrite_scan = systable_beginscan(rewrite_desc,
RewriteRelRulenameIndex,
true, SnapshotNow,
1, &key);
while (HeapTupleIsValid(pg_rewrite_tuple = systable_getnext(pg_rewrite_scan)))
while (HeapTupleIsValid(rewrite_tuple = systable_getnext(rewrite_scan)))
{
Form_pg_rewrite rewrite_form = (Form_pg_rewrite) GETSTRUCT(pg_rewrite_tuple);
Form_pg_rewrite rewrite_form = (Form_pg_rewrite) GETSTRUCT(rewrite_tuple);
bool isnull;
Datum ruleaction;
Datum rule_evqual;
@@ -697,7 +701,7 @@ RelationBuildRuleLock(Relation relation)
rule = (RewriteRule *) MemoryContextAlloc(rulescxt,
sizeof(RewriteRule));
rule->ruleId = pg_rewrite_tuple->t_data->t_oid;
rule->ruleId = rewrite_tuple->t_data->t_oid;
rule->event = rewrite_form->ev_type - '0';
rule->attrno = rewrite_form->ev_attr;
@@ -705,9 +709,9 @@ RelationBuildRuleLock(Relation relation)
/* Must use heap_getattr to fetch ev_qual and ev_action */
ruleaction = heap_getattr(pg_rewrite_tuple,
ruleaction = heap_getattr(rewrite_tuple,
Anum_pg_rewrite_ev_action,
pg_rewrite_tupdesc,
rewrite_tupdesc,
&isnull);
Assert(!isnull);
ruleaction_str = DatumGetCString(DirectFunctionCall1(textout,
@@ -717,13 +721,13 @@ RelationBuildRuleLock(Relation relation)
MemoryContextSwitchTo(oldcxt);
pfree(ruleaction_str);
rule_evqual = heap_getattr(pg_rewrite_tuple,
rule_evqual = heap_getattr(rewrite_tuple,
Anum_pg_rewrite_ev_qual,
pg_rewrite_tupdesc,
rewrite_tupdesc,
&isnull);
Assert(!isnull);
rule_evqual_str = DatumGetCString(DirectFunctionCall1(textout,
rule_evqual));
rule_evqual));
oldcxt = MemoryContextSwitchTo(rulescxt);
rule->qual = (Node *) stringToNode(rule_evqual_str);
MemoryContextSwitchTo(oldcxt);
@@ -741,8 +745,8 @@ RelationBuildRuleLock(Relation relation)
/*
* end the scan and close the attribute relation
*/
systable_endscan(pg_rewrite_scan);
heap_close(pg_rewrite_desc, AccessShareLock);
systable_endscan(rewrite_scan);
heap_close(rewrite_desc, AccessShareLock);
/*
* form a RuleLock and insert into relation
@@ -764,9 +768,13 @@ RelationBuildRuleLock(Relation relation)
static bool
equalRuleLocks(RuleLock *rlock1, RuleLock *rlock2)
{
int i,
j;
int i;
/*
* As of 7.3 we assume the rule ordering is repeatable,
* because RelationBuildRuleLock should read 'em in a
* consistent order. So just compare corresponding slots.
*/
if (rlock1 != NULL)
{
if (rlock2 == NULL)
@@ -776,21 +784,9 @@ equalRuleLocks(RuleLock *rlock1, RuleLock *rlock2)
for (i = 0; i < rlock1->numLocks; i++)
{
RewriteRule *rule1 = rlock1->rules[i];
RewriteRule *rule2 = NULL;
RewriteRule *rule2 = rlock2->rules[i];
/*
* We can't assume that the rules are always read from
* pg_rewrite in the same order; so use the rule OIDs to
* identify the rules to compare. (We assume here that the
* same OID won't appear twice in either ruleset.)
*/
for (j = 0; j < rlock2->numLocks; j++)
{
rule2 = rlock2->rules[j];
if (rule1->ruleId == rule2->ruleId)
break;
}
if (j >= rlock2->numLocks)
if (rule1->ruleId != rule2->ruleId)
return false;
if (rule1->event != rule2->event)
return false;