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postgresql/src/backend/commands/trigger.c

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/*-------------------------------------------------------------------------
*
* trigger.c
* PostgreSQL TRIGGERs support code.
*
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/trigger.c,v 1.120 2002/06/20 20:29:27 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "catalog/catalog.h"
#include "catalog/catname.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/pg_language.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_trigger.h"
#include "commands/comment.h"
#include "commands/trigger.h"
#include "executor/executor.h"
#include "miscadmin.h"
#include "parser/parse_func.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
static void InsertTrigger(TriggerDesc *trigdesc, Trigger *trigger, int indx);
static HeapTuple GetTupleForTrigger(EState *estate,
ResultRelInfo *relinfo,
ItemPointer tid,
TupleTableSlot **newSlot);
static HeapTuple ExecCallTriggerFunc(TriggerData *trigdata,
FmgrInfo *finfo,
MemoryContext per_tuple_context);
static void DeferredTriggerSaveEvent(ResultRelInfo *relinfo, int event,
HeapTuple oldtup, HeapTuple newtup);
static void DeferredTriggerExecute(DeferredTriggerEvent event, int itemno,
Relation rel, FmgrInfo *finfo,
MemoryContext per_tuple_context);
void
CreateTrigger(CreateTrigStmt *stmt)
{
int16 tgtype;
int16 tgattr[FUNC_MAX_ARGS];
Datum values[Natts_pg_trigger];
char nulls[Natts_pg_trigger];
Relation rel;
AclResult aclresult;
Relation tgrel;
SysScanDesc tgscan;
ScanKeyData key;
Relation pgrel;
HeapTuple tuple;
Relation idescs[Num_pg_trigger_indices];
Relation ridescs[Num_pg_class_indices];
Oid fargtypes[FUNC_MAX_ARGS];
Oid funcoid;
Oid funclang;
int found = 0;
int i;
char constrtrigname[NAMEDATALEN];
char *constrname = "";
Oid constrrelid = InvalidOid;
rel = heap_openrv(stmt->relation, AccessExclusiveLock);
if (rel->rd_rel->relkind != RELKIND_RELATION)
elog(ERROR, "CreateTrigger: relation \"%s\" is not a table",
stmt->relation->relname);
if (!allowSystemTableMods && IsSystemRelation(rel))
elog(ERROR, "CreateTrigger: can't create trigger for system relation %s",
stmt->relation->relname);
aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
stmt->isconstraint ? ACL_REFERENCES : ACL_TRIGGER);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, RelationGetRelationName(rel));
/*
* 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;
if (stmt->constrrel != NULL)
constrrelid = RangeVarGetRelid(stmt->constrrel, false);
else
constrrelid = InvalidOid;
}
TRIGGER_CLEAR_TYPE(tgtype);
if (stmt->before)
TRIGGER_SETT_BEFORE(tgtype);
if (stmt->row)
TRIGGER_SETT_ROW(tgtype);
else
elog(ERROR, "CreateTrigger: STATEMENT triggers are unimplemented, yet");
for (i = 0; i < 3 && stmt->actions[i]; i++)
{
switch (stmt->actions[i])
{
case 'i':
if (TRIGGER_FOR_INSERT(tgtype))
elog(ERROR, "CreateTrigger: double INSERT event specified");
TRIGGER_SETT_INSERT(tgtype);
break;
case 'd':
if (TRIGGER_FOR_DELETE(tgtype))
elog(ERROR, "CreateTrigger: double DELETE event specified");
TRIGGER_SETT_DELETE(tgtype);
break;
case 'u':
if (TRIGGER_FOR_UPDATE(tgtype))
elog(ERROR, "CreateTrigger: double UPDATE event specified");
TRIGGER_SETT_UPDATE(tgtype);
break;
default:
elog(ERROR, "CreateTrigger: unknown event specified");
break;
}
}
/*
* 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,
F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
tgscan = systable_beginscan(tgrel, TriggerRelidNameIndex, true,
SnapshotNow, 1, &key);
while (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
{
Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
if (namestrcmp(&(pg_trigger->tgname), stmt->trigname) == 0)
elog(ERROR, "CreateTrigger: trigger %s already defined on relation %s",
stmt->trigname, stmt->relation->relname);
found++;
}
systable_endscan(tgscan);
/*
* Find and validate the trigger function.
*/
MemSet(fargtypes, 0, FUNC_MAX_ARGS * sizeof(Oid));
funcoid = LookupFuncName(stmt->funcname, 0, fargtypes);
if (!OidIsValid(funcoid))
elog(ERROR, "CreateTrigger: function %s() does not exist",
NameListToString(stmt->funcname));
tuple = SearchSysCache(PROCOID,
ObjectIdGetDatum(funcoid),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "CreateTrigger: function %s() does not exist",
NameListToString(stmt->funcname));
if (((Form_pg_proc) GETSTRUCT(tuple))->prorettype != 0)
elog(ERROR, "CreateTrigger: function %s() must return OPAQUE",
NameListToString(stmt->funcname));
funclang = ((Form_pg_proc) GETSTRUCT(tuple))->prolang;
ReleaseSysCache(tuple);
if (funclang != ClanguageId && funclang != INTERNALlanguageId)
{
HeapTuple langTup;
langTup = SearchSysCache(LANGOID,
ObjectIdGetDatum(funclang),
0, 0, 0);
if (!HeapTupleIsValid(langTup))
elog(ERROR, "CreateTrigger: cache lookup for language %u failed",
funclang);
if (((Form_pg_language) GETSTRUCT(langTup))->lanispl == false)
elog(ERROR, "CreateTrigger: only internal, C and PL functions are supported");
ReleaseSysCache(langTup);
}
/*
* Build the new pg_trigger tuple.
*/
MemSet(nulls, ' ', Natts_pg_trigger * sizeof(char));
values[Anum_pg_trigger_tgrelid - 1] = ObjectIdGetDatum(RelationGetRelid(rel));
values[Anum_pg_trigger_tgname - 1] = DirectFunctionCall1(namein,
CStringGetDatum(stmt->trigname));
values[Anum_pg_trigger_tgfoid - 1] = ObjectIdGetDatum(funcoid);
values[Anum_pg_trigger_tgtype - 1] = Int16GetDatum(tgtype);
values[Anum_pg_trigger_tgenabled - 1] = BoolGetDatum(true);
values[Anum_pg_trigger_tgisconstraint - 1] = BoolGetDatum(stmt->isconstraint);
values[Anum_pg_trigger_tgconstrname - 1] = PointerGetDatum(constrname);
values[Anum_pg_trigger_tgconstrrelid - 1] = ObjectIdGetDatum(constrrelid);
values[Anum_pg_trigger_tgdeferrable - 1] = BoolGetDatum(stmt->deferrable);
values[Anum_pg_trigger_tginitdeferred - 1] = BoolGetDatum(stmt->initdeferred);
if (stmt->args)
{
List *le;
char *args;
int16 nargs = length(stmt->args);
int len = 0;
foreach(le, stmt->args)
{
char *ar = ((Value *) lfirst(le))->val.str;
len += strlen(ar) + 4;
for (; *ar; ar++)
{
if (*ar == '\\')
len++;
}
}
args = (char *) palloc(len + 1);
args[0] = '\0';
foreach(le, stmt->args)
{
char *s = ((Value *) lfirst(le))->val.str;
char *d = args + strlen(args);
while (*s)
{
if (*s == '\\')
*d++ = '\\';
*d++ = *s++;
}
strcpy(d, "\\000");
}
values[Anum_pg_trigger_tgnargs - 1] = Int16GetDatum(nargs);
values[Anum_pg_trigger_tgargs - 1] = DirectFunctionCall1(byteain,
CStringGetDatum(args));
}
else
{
values[Anum_pg_trigger_tgnargs - 1] = Int16GetDatum(0);
values[Anum_pg_trigger_tgargs - 1] = DirectFunctionCall1(byteain,
CStringGetDatum(""));
}
MemSet(tgattr, 0, FUNC_MAX_ARGS * sizeof(int16));
values[Anum_pg_trigger_tgattr - 1] = PointerGetDatum(tgattr);
tuple = heap_formtuple(tgrel->rd_att, values, nulls);
/*
* Insert tuple into pg_trigger.
*/
simple_heap_insert(tgrel, tuple);
CatalogOpenIndices(Num_pg_trigger_indices, Name_pg_trigger_indices, idescs);
CatalogIndexInsert(idescs, Num_pg_trigger_indices, tgrel, tuple);
CatalogCloseIndices(Num_pg_trigger_indices, idescs);
heap_freetuple(tuple);
heap_close(tgrel, RowExclusiveLock);
pfree(DatumGetPointer(values[Anum_pg_trigger_tgname - 1]));
pfree(DatumGetPointer(values[Anum_pg_trigger_tgargs - 1]));
/*
* Update relation's pg_class entry. Crucial side-effect: other
* backends (and this one too!) are sent SI message to make them
* rebuild relcache entries.
*/
pgrel = heap_openr(RelationRelationName, RowExclusiveLock);
tuple = SearchSysCacheCopy(RELOID,
ObjectIdGetDatum(RelationGetRelid(rel)),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "CreateTrigger: relation %s not found in pg_class",
stmt->relation->relname);
((Form_pg_class) GETSTRUCT(tuple))->reltriggers = found + 1;
simple_heap_update(pgrel, &tuple->t_self, tuple);
CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, ridescs);
CatalogIndexInsert(ridescs, Num_pg_class_indices, pgrel, tuple);
CatalogCloseIndices(Num_pg_class_indices, ridescs);
heap_freetuple(tuple);
heap_close(pgrel, RowExclusiveLock);
/*
* We used to try to update the rel's relcache entry here, but that's
* fairly pointless since it will happen as a byproduct of the
* upcoming CommandCounterIncrement...
*/
/* Keep lock on target rel until end of xact */
heap_close(rel, NoLock);
}
/*
* DropTrigger - drop an individual trigger by name
*/
void
DropTrigger(Oid relid, const char *trigname)
{
Relation rel;
Relation tgrel;
SysScanDesc tgscan;
ScanKeyData key;
Relation pgrel;
HeapTuple tuple;
Relation ridescs[Num_pg_class_indices];
int remaining = 0;
int found = 0;
rel = heap_open(relid, AccessExclusiveLock);
if (rel->rd_rel->relkind != RELKIND_RELATION)
elog(ERROR, "DropTrigger: relation \"%s\" is not a table",
RelationGetRelationName(rel));
if (!allowSystemTableMods && IsSystemRelation(rel))
elog(ERROR, "DropTrigger: can't drop trigger for system relation %s",
RelationGetRelationName(rel));
if (!pg_class_ownercheck(relid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
/*
* Search pg_trigger, delete target trigger, count remaining triggers
* 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,
F_OIDEQ,
ObjectIdGetDatum(relid));
tgscan = systable_beginscan(tgrel, TriggerRelidNameIndex, true,
SnapshotNow, 1, &key);
while (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
{
Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
if (namestrcmp(&(pg_trigger->tgname), trigname) == 0)
{
/* Delete any comments associated with this trigger */
DeleteComments(tuple->t_data->t_oid, RelationGetRelid(tgrel));
simple_heap_delete(tgrel, &tuple->t_self);
found++;
}
else
remaining++;
}
systable_endscan(tgscan);
heap_close(tgrel, RowExclusiveLock);
if (found == 0)
elog(ERROR, "DropTrigger: there is no trigger %s on relation %s",
trigname, RelationGetRelationName(rel));
if (found > 1) /* shouldn't happen */
elog(NOTICE, "DropTrigger: found (and deleted) %d triggers %s on relation %s",
found, trigname, RelationGetRelationName(rel));
/*
* Update relation's pg_class entry. Crucial side-effect: other
* backends (and this one too!) are sent SI message to make them
* rebuild relcache entries.
*/
pgrel = heap_openr(RelationRelationName, RowExclusiveLock);
tuple = SearchSysCacheCopy(RELOID,
ObjectIdGetDatum(relid),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "DropTrigger: relation %s not found in pg_class",
RelationGetRelationName(rel));
((Form_pg_class) GETSTRUCT(tuple))->reltriggers = remaining;
simple_heap_update(pgrel, &tuple->t_self, tuple);
CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, ridescs);
CatalogIndexInsert(ridescs, Num_pg_class_indices, pgrel, tuple);
CatalogCloseIndices(Num_pg_class_indices, ridescs);
heap_freetuple(tuple);
heap_close(pgrel, RowExclusiveLock);
/* Keep lock on target rel until end of xact */
heap_close(rel, NoLock);
}
/*
* Remove all triggers for a relation that's being deleted.
*/
void
RelationRemoveTriggers(Relation rel)
{
Relation tgrel;
SysScanDesc tgscan;
ScanKeyData key;
HeapTuple tup;
bool found = false;
tgrel = heap_openr(TriggerRelationName, RowExclusiveLock);
ScanKeyEntryInitialize(&key, 0,
Anum_pg_trigger_tgrelid,
F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
tgscan = systable_beginscan(tgrel, TriggerRelidNameIndex, true,
SnapshotNow, 1, &key);
while (HeapTupleIsValid(tup = systable_getnext(tgscan)))
{
/* Delete any comments associated with this trigger */
DeleteComments(tup->t_data->t_oid, RelationGetRelid(tgrel));
simple_heap_delete(tgrel, &tup->t_self);
found = true;
}
systable_endscan(tgscan);
/*
* If we deleted any triggers, must update pg_class entry and advance
* command counter to make the updated entry visible. This is fairly
* annoying, since we'e just going to drop the durn thing later, but
* it's necessary to have a consistent state in case we do
* CommandCounterIncrement() below --- if RelationBuildTriggers()
* runs, it will complain otherwise. Perhaps RelationBuildTriggers()
* shouldn't be so picky...
*/
if (found)
{
Relation pgrel;
Relation ridescs[Num_pg_class_indices];
pgrel = heap_openr(RelationRelationName, RowExclusiveLock);
tup = SearchSysCacheCopy(RELOID,
ObjectIdGetDatum(RelationGetRelid(rel)),
0, 0, 0);
if (!HeapTupleIsValid(tup))
elog(ERROR, "RelationRemoveTriggers: relation %u not found in pg_class",
RelationGetRelid(rel));
((Form_pg_class) GETSTRUCT(tup))->reltriggers = 0;
simple_heap_update(pgrel, &tup->t_self, tup);
CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, ridescs);
CatalogIndexInsert(ridescs, Num_pg_class_indices, pgrel, tup);
CatalogCloseIndices(Num_pg_class_indices, ridescs);
heap_freetuple(tup);
heap_close(pgrel, RowExclusiveLock);
CommandCounterIncrement();
}
/*
* Also drop all constraint triggers referencing this relation
*/
ScanKeyEntryInitialize(&key, 0,
Anum_pg_trigger_tgconstrrelid,
F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
tgscan = systable_beginscan(tgrel, TriggerConstrRelidIndex, true,
SnapshotNow, 1, &key);
while (HeapTupleIsValid(tup = systable_getnext(tgscan)))
{
Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tup);
elog(NOTICE, "DROP TABLE implicitly drops referential integrity trigger from table \"%s\"",
get_rel_name(pg_trigger->tgrelid));
DropTrigger(pg_trigger->tgrelid, NameStr(pg_trigger->tgname));
/*
* Need to do a command counter increment here to show up new
* pg_class.reltriggers in the next loop iteration (in case there
* are multiple referential integrity action triggers for the same
* FK table defined on the PK table).
*/
CommandCounterIncrement();
}
systable_endscan(tgscan);
heap_close(tgrel, RowExclusiveLock);
}
/*
* renametrig - changes the name of a trigger on a relation
*
* trigger name is changed in trigger catalog.
* No record of the previous name is kept.
*
* get proper relrelation from relation catalog (if not arg)
* scan trigger catalog
* for name conflict (within rel)
* for original trigger (if not arg)
* modify tgname in trigger tuple
* update row in catalog
*/
void
renametrig(Oid relid,
const char *oldname,
const char *newname)
{
Relation targetrel;
Relation tgrel;
HeapTuple tuple;
SysScanDesc tgscan;
ScanKeyData key[2];
Relation idescs[Num_pg_trigger_indices];
/*
* Grab an exclusive lock on the target table, which we will NOT
* release until end of transaction.
*/
targetrel = heap_open(relid, AccessExclusiveLock);
/*
* Scan pg_trigger twice for existing triggers on relation. We do this in
* order to ensure a trigger does not exist with newname (The unique index
* on tgrelid/tgname would complain anyway) and to ensure a trigger does
* exist with oldname.
*
* 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);
/*
* First pass -- look for name conflict
*/
ScanKeyEntryInitialize(&key[0], 0,
Anum_pg_trigger_tgrelid,
F_OIDEQ,
ObjectIdGetDatum(relid));
ScanKeyEntryInitialize(&key[1], 0,
Anum_pg_trigger_tgname,
F_NAMEEQ,
PointerGetDatum(newname));
tgscan = systable_beginscan(tgrel, TriggerRelidNameIndex, true,
SnapshotNow, 2, key);
if (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
elog(ERROR, "renametrig: trigger %s already defined on relation %s",
newname, RelationGetRelationName(targetrel));
systable_endscan(tgscan);
/*
* Second pass -- look for trigger existing with oldname and update
*/
ScanKeyEntryInitialize(&key[0], 0,
Anum_pg_trigger_tgrelid,
F_OIDEQ,
ObjectIdGetDatum(relid));
ScanKeyEntryInitialize(&key[1], 0,
Anum_pg_trigger_tgname,
F_NAMEEQ,
PointerGetDatum(oldname));
tgscan = systable_beginscan(tgrel, TriggerRelidNameIndex, true,
SnapshotNow, 2, key);
if (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
{
/*
* Update pg_trigger tuple with new tgname.
*/
tuple = heap_copytuple(tuple); /* need a modifiable copy */
namestrcpy(&((Form_pg_trigger) GETSTRUCT(tuple))->tgname, newname);
simple_heap_update(tgrel, &tuple->t_self, tuple);
/*
* keep system catalog indices current
*/
CatalogOpenIndices(Num_pg_trigger_indices, Name_pg_trigger_indices, idescs);
CatalogIndexInsert(idescs, Num_pg_trigger_indices, tgrel, tuple);
CatalogCloseIndices(Num_pg_trigger_indices, idescs);
/*
* Invalidate relation's relcache entry so that other backends (and
* this one too!) are sent SI message to make them rebuild relcache
* entries. (Ideally this should happen automatically...)
*/
CacheInvalidateRelcache(relid);
}
else
{
elog(ERROR, "renametrig: trigger %s not defined on relation %s",
oldname, RelationGetRelationName(targetrel));
}
systable_endscan(tgscan);
heap_close(tgrel, RowExclusiveLock);
/*
* Close rel, but keep exclusive lock!
*/
heap_close(targetrel, NoLock);
}
/*
* Build trigger data to attach to the given relcache entry.
*
* Note that trigger data must be allocated in CacheMemoryContext
* to ensure it survives as long as the relcache entry. But we
* are probably running in a less long-lived working context.
*/
void
RelationBuildTriggers(Relation relation)
{
TriggerDesc *trigdesc;
int ntrigs = relation->rd_rel->reltriggers;
Trigger *triggers;
int found = 0;
Relation tgrel;
ScanKeyData skey;
SysScanDesc tgscan;
HeapTuple htup;
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,
(RegProcedure) F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(relation)));
tgrel = heap_openr(TriggerRelationName, AccessShareLock);
tgscan = systable_beginscan(tgrel, TriggerRelidNameIndex, true,
SnapshotNow, 1, &skey);
while (HeapTupleIsValid(htup = systable_getnext(tgscan)))
{
Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(htup);
Trigger *build;
if (found >= ntrigs)
elog(ERROR, "RelationBuildTriggers: unexpected record found for rel %s",
RelationGetRelationName(relation));
build = &(triggers[found]);
build->tgoid = htup->t_data->t_oid;
build->tgname = MemoryContextStrdup(CacheMemoryContext,
DatumGetCString(DirectFunctionCall1(nameout,
NameGetDatum(&pg_trigger->tgname))));
build->tgfoid = pg_trigger->tgfoid;
build->tgtype = pg_trigger->tgtype;
build->tgenabled = pg_trigger->tgenabled;
build->tgisconstraint = pg_trigger->tgisconstraint;
build->tgconstrrelid = pg_trigger->tgconstrrelid;
build->tgdeferrable = pg_trigger->tgdeferrable;
build->tginitdeferred = pg_trigger->tginitdeferred;
build->tgnargs = pg_trigger->tgnargs;
memcpy(build->tgattr, &(pg_trigger->tgattr),
FUNC_MAX_ARGS * sizeof(int16));
if (build->tgnargs > 0)
{
char *p;
int i;
val = (struct varlena *) fastgetattr(htup,
Anum_pg_trigger_tgargs,
tgrel->rd_att, &isnull);
if (isnull)
elog(ERROR, "RelationBuildTriggers: tgargs IS NULL for rel %s",
RelationGetRelationName(relation));
p = (char *) VARDATA(val);
build->tgargs = (char **)
MemoryContextAlloc(CacheMemoryContext,
build->tgnargs * sizeof(char *));
for (i = 0; i < build->tgnargs; i++)
{
build->tgargs[i] = MemoryContextStrdup(CacheMemoryContext,
p);
p += strlen(p) + 1;
}
}
else
build->tgargs = NULL;
found++;
}
systable_endscan(tgscan);
heap_close(tgrel, AccessShareLock);
if (found != ntrigs)
elog(ERROR, "RelationBuildTriggers: %d record(s) not found for rel %s",
ntrigs - found,
RelationGetRelationName(relation));
/* Build trigdesc */
trigdesc = (TriggerDesc *) MemoryContextAlloc(CacheMemoryContext,
sizeof(TriggerDesc));
MemSet(trigdesc, 0, sizeof(TriggerDesc));
trigdesc->triggers = triggers;
trigdesc->numtriggers = ntrigs;
for (found = 0; found < ntrigs; found++)
InsertTrigger(trigdesc, &(triggers[found]), found);
relation->trigdesc = trigdesc;
}
/* Insert the given trigger into the appropriate index list(s) for it */
static void
InsertTrigger(TriggerDesc *trigdesc, Trigger *trigger, int indx)
{
uint16 *n;
int **t,
**tp;
if (TRIGGER_FOR_ROW(trigger->tgtype))
{
/* ROW trigger */
if (TRIGGER_FOR_BEFORE(trigger->tgtype))
{
n = trigdesc->n_before_row;
t = trigdesc->tg_before_row;
}
else
{
n = trigdesc->n_after_row;
t = trigdesc->tg_after_row;
}
}
else
{
/* STATEMENT trigger */
if (TRIGGER_FOR_BEFORE(trigger->tgtype))
{
n = trigdesc->n_before_statement;
t = trigdesc->tg_before_statement;
}
else
{
n = trigdesc->n_after_statement;
t = trigdesc->tg_after_statement;
}
}
if (TRIGGER_FOR_INSERT(trigger->tgtype))
{
tp = &(t[TRIGGER_EVENT_INSERT]);
if (*tp == NULL)
*tp = (int *) MemoryContextAlloc(CacheMemoryContext,
sizeof(int));
else
*tp = (int *) repalloc(*tp, (n[TRIGGER_EVENT_INSERT] + 1) *
sizeof(int));
(*tp)[n[TRIGGER_EVENT_INSERT]] = indx;
(n[TRIGGER_EVENT_INSERT])++;
}
if (TRIGGER_FOR_DELETE(trigger->tgtype))
{
tp = &(t[TRIGGER_EVENT_DELETE]);
if (*tp == NULL)
*tp = (int *) MemoryContextAlloc(CacheMemoryContext,
sizeof(int));
else
*tp = (int *) repalloc(*tp, (n[TRIGGER_EVENT_DELETE] + 1) *
sizeof(int));
(*tp)[n[TRIGGER_EVENT_DELETE]] = indx;
(n[TRIGGER_EVENT_DELETE])++;
}
if (TRIGGER_FOR_UPDATE(trigger->tgtype))
{
tp = &(t[TRIGGER_EVENT_UPDATE]);
if (*tp == NULL)
*tp = (int *) MemoryContextAlloc(CacheMemoryContext,
sizeof(int));
else
*tp = (int *) repalloc(*tp, (n[TRIGGER_EVENT_UPDATE] + 1) *
sizeof(int));
(*tp)[n[TRIGGER_EVENT_UPDATE]] = indx;
(n[TRIGGER_EVENT_UPDATE])++;
}
}
void
FreeTriggerDesc(TriggerDesc *trigdesc)
{
int **t;
Trigger *trigger;
int i;
if (trigdesc == NULL)
return;
t = trigdesc->tg_before_statement;
for (i = 0; i < TRIGGER_NUM_EVENT_CLASSES; i++)
if (t[i] != NULL)
pfree(t[i]);
t = trigdesc->tg_before_row;
for (i = 0; i < TRIGGER_NUM_EVENT_CLASSES; i++)
if (t[i] != NULL)
pfree(t[i]);
t = trigdesc->tg_after_row;
for (i = 0; i < TRIGGER_NUM_EVENT_CLASSES; i++)
if (t[i] != NULL)
pfree(t[i]);
t = trigdesc->tg_after_statement;
for (i = 0; i < TRIGGER_NUM_EVENT_CLASSES; i++)
if (t[i] != NULL)
pfree(t[i]);
trigger = trigdesc->triggers;
for (i = 0; i < trigdesc->numtriggers; i++)
{
pfree(trigger->tgname);
if (trigger->tgnargs > 0)
{
while (--(trigger->tgnargs) >= 0)
pfree(trigger->tgargs[trigger->tgnargs]);
pfree(trigger->tgargs);
}
trigger++;
}
pfree(trigdesc->triggers);
pfree(trigdesc);
}
bool
equalTriggerDescs(TriggerDesc *trigdesc1, TriggerDesc *trigdesc2)
{
int i,
j;
/*
* 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)
{
if (trigdesc2 == NULL)
return false;
if (trigdesc1->numtriggers != trigdesc2->numtriggers)
return false;
for (i = 0; i < trigdesc1->numtriggers; i++)
{
Trigger *trig1 = trigdesc1->triggers + i;
Trigger *trig2 = trigdesc2->triggers + i;
if (trig1->tgoid != trig2->tgoid)
return false;
if (strcmp(trig1->tgname, trig2->tgname) != 0)
return false;
if (trig1->tgfoid != trig2->tgfoid)
return false;
if (trig1->tgtype != trig2->tgtype)
return false;
if (trig1->tgenabled != trig2->tgenabled)
return false;
if (trig1->tgisconstraint != trig2->tgisconstraint)
return false;
if (trig1->tgconstrrelid != trig2->tgconstrrelid)
return false;
if (trig1->tgdeferrable != trig2->tgdeferrable)
return false;
if (trig1->tginitdeferred != trig2->tginitdeferred)
return false;
if (trig1->tgnargs != trig2->tgnargs)
return false;
if (memcmp(trig1->tgattr, trig2->tgattr,
sizeof(trig1->tgattr)) != 0)
return false;
for (j = 0; j < trig1->tgnargs; j++)
if (strcmp(trig1->tgargs[j], trig2->tgargs[j]) != 0)
return false;
}
}
else if (trigdesc2 != NULL)
return false;
return true;
}
/*
* Call a trigger function.
*
* trigdata: trigger descriptor.
* finfo: possibly-cached call info for the function.
* per_tuple_context: memory context to execute the function in.
*
* Returns the tuple (or NULL) as returned by the function.
*/
static HeapTuple
ExecCallTriggerFunc(TriggerData *trigdata,
FmgrInfo *finfo,
MemoryContext per_tuple_context)
{
FunctionCallInfoData fcinfo;
Datum result;
MemoryContext oldContext;
/*
* We cache fmgr lookup info, to avoid making the lookup again on each
* call.
*/
if (finfo->fn_oid == InvalidOid)
fmgr_info(trigdata->tg_trigger->tgfoid, finfo);
Assert(finfo->fn_oid == trigdata->tg_trigger->tgfoid);
/*
* Do the function evaluation in the per-tuple memory context, so that
* leaked memory will be reclaimed once per tuple. Note in particular
* that any new tuple created by the trigger function will live till
* the end of the tuple cycle.
*/
oldContext = MemoryContextSwitchTo(per_tuple_context);
/*
* Call the function, passing no arguments but setting a context.
*/
MemSet(&fcinfo, 0, sizeof(fcinfo));
fcinfo.flinfo = finfo;
fcinfo.context = (Node *) trigdata;
result = FunctionCallInvoke(&fcinfo);
MemoryContextSwitchTo(oldContext);
/*
* Trigger protocol allows function to return a null pointer, but NOT
* to set the isnull result flag.
*/
if (fcinfo.isnull)
elog(ERROR, "ExecCallTriggerFunc: function %u returned NULL",
fcinfo.flinfo->fn_oid);
return (HeapTuple) DatumGetPointer(result);
}
HeapTuple
ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
HeapTuple trigtuple)
{
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
int ntrigs = trigdesc->n_before_row[TRIGGER_EVENT_INSERT];
int *tgindx = trigdesc->tg_before_row[TRIGGER_EVENT_INSERT];
HeapTuple newtuple = trigtuple;
HeapTuple oldtuple;
TriggerData LocTriggerData;
int i;
/* Allocate cache space for fmgr lookup info, if not done yet */
if (relinfo->ri_TrigFunctions == NULL)
{
relinfo->ri_TrigFunctions = (FmgrInfo *)
palloc(trigdesc->numtriggers * sizeof(FmgrInfo));
MemSet(relinfo->ri_TrigFunctions, 0,
trigdesc->numtriggers * sizeof(FmgrInfo));
}
LocTriggerData.type = T_TriggerData;
LocTriggerData.tg_event = TRIGGER_EVENT_INSERT | TRIGGER_EVENT_ROW | TRIGGER_EVENT_BEFORE;
LocTriggerData.tg_relation = relinfo->ri_RelationDesc;
LocTriggerData.tg_newtuple = NULL;
for (i = 0; i < ntrigs; i++)
{
Trigger *trigger = &trigdesc->triggers[tgindx[i]];
if (!trigger->tgenabled)
continue;
LocTriggerData.tg_trigtuple = oldtuple = newtuple;
LocTriggerData.tg_trigger = trigger;
newtuple = ExecCallTriggerFunc(&LocTriggerData,
relinfo->ri_TrigFunctions + tgindx[i],
GetPerTupleMemoryContext(estate));
if (oldtuple != newtuple && oldtuple != trigtuple)
heap_freetuple(oldtuple);
if (newtuple == NULL)
break;
}
return newtuple;
}
void
ExecARInsertTriggers(EState *estate, ResultRelInfo *relinfo,
HeapTuple trigtuple)
{
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
if (trigdesc->n_after_row[TRIGGER_EVENT_INSERT] > 0)
DeferredTriggerSaveEvent(relinfo, TRIGGER_EVENT_INSERT,
NULL, trigtuple);
}
bool
ExecBRDeleteTriggers(EState *estate, ResultRelInfo *relinfo,
ItemPointer tupleid)
{
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
int ntrigs = trigdesc->n_before_row[TRIGGER_EVENT_DELETE];
int *tgindx = trigdesc->tg_before_row[TRIGGER_EVENT_DELETE];
TriggerData LocTriggerData;
HeapTuple trigtuple;
HeapTuple newtuple = NULL;
TupleTableSlot *newSlot;
int i;
trigtuple = GetTupleForTrigger(estate, relinfo, tupleid, &newSlot);
if (trigtuple == NULL)
return false;
/* Allocate cache space for fmgr lookup info, if not done yet */
if (relinfo->ri_TrigFunctions == NULL)
{
relinfo->ri_TrigFunctions = (FmgrInfo *)
palloc(trigdesc->numtriggers * sizeof(FmgrInfo));
MemSet(relinfo->ri_TrigFunctions, 0,
trigdesc->numtriggers * sizeof(FmgrInfo));
}
LocTriggerData.type = T_TriggerData;
LocTriggerData.tg_event = TRIGGER_EVENT_DELETE | TRIGGER_EVENT_ROW | TRIGGER_EVENT_BEFORE;
LocTriggerData.tg_relation = relinfo->ri_RelationDesc;
LocTriggerData.tg_newtuple = NULL;
for (i = 0; i < ntrigs; i++)
{
Trigger *trigger = &trigdesc->triggers[tgindx[i]];
if (!trigger->tgenabled)
continue;
LocTriggerData.tg_trigtuple = trigtuple;
LocTriggerData.tg_trigger = trigger;
newtuple = ExecCallTriggerFunc(&LocTriggerData,
relinfo->ri_TrigFunctions + tgindx[i],
GetPerTupleMemoryContext(estate));
if (newtuple == NULL)
break;
if (newtuple != trigtuple)
heap_freetuple(newtuple);
}
heap_freetuple(trigtuple);
return (newtuple == NULL) ? false : true;
}
void
ExecARDeleteTriggers(EState *estate, ResultRelInfo *relinfo,
ItemPointer tupleid)
{
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
if (trigdesc->n_after_row[TRIGGER_EVENT_DELETE] > 0)
{
HeapTuple trigtuple = GetTupleForTrigger(estate, relinfo,
tupleid, NULL);
DeferredTriggerSaveEvent(relinfo, TRIGGER_EVENT_DELETE,
trigtuple, NULL);
heap_freetuple(trigtuple);
}
}
HeapTuple
ExecBRUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
ItemPointer tupleid, HeapTuple newtuple)
{
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
int ntrigs = trigdesc->n_before_row[TRIGGER_EVENT_UPDATE];
int *tgindx = trigdesc->tg_before_row[TRIGGER_EVENT_UPDATE];
TriggerData LocTriggerData;
HeapTuple trigtuple;
HeapTuple oldtuple;
HeapTuple intuple = newtuple;
TupleTableSlot *newSlot;
int i;
trigtuple = GetTupleForTrigger(estate, relinfo, tupleid, &newSlot);
if (trigtuple == NULL)
return NULL;
/*
* In READ COMMITTED isolevel it's possible that newtuple was changed
* due to concurrent update.
*/
if (newSlot != NULL)
intuple = newtuple = ExecRemoveJunk(estate->es_junkFilter, newSlot);
/* Allocate cache space for fmgr lookup info, if not done yet */
if (relinfo->ri_TrigFunctions == NULL)
{
relinfo->ri_TrigFunctions = (FmgrInfo *)
palloc(trigdesc->numtriggers * sizeof(FmgrInfo));
MemSet(relinfo->ri_TrigFunctions, 0,
trigdesc->numtriggers * sizeof(FmgrInfo));
}
LocTriggerData.type = T_TriggerData;
LocTriggerData.tg_event = TRIGGER_EVENT_UPDATE | TRIGGER_EVENT_ROW | TRIGGER_EVENT_BEFORE;
LocTriggerData.tg_relation = relinfo->ri_RelationDesc;
for (i = 0; i < ntrigs; i++)
{
Trigger *trigger = &trigdesc->triggers[tgindx[i]];
if (!trigger->tgenabled)
continue;
LocTriggerData.tg_trigtuple = trigtuple;
LocTriggerData.tg_newtuple = oldtuple = newtuple;
LocTriggerData.tg_trigger = trigger;
newtuple = ExecCallTriggerFunc(&LocTriggerData,
relinfo->ri_TrigFunctions + tgindx[i],
GetPerTupleMemoryContext(estate));
if (oldtuple != newtuple && oldtuple != intuple)
heap_freetuple(oldtuple);
if (newtuple == NULL)
break;
}
heap_freetuple(trigtuple);
return newtuple;
}
void
ExecARUpdateTriggers(EState *estate, ResultRelInfo *relinfo,
ItemPointer tupleid, HeapTuple newtuple)
{
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
if (trigdesc->n_after_row[TRIGGER_EVENT_UPDATE] > 0)
{
HeapTuple trigtuple = GetTupleForTrigger(estate, relinfo,
tupleid, NULL);
DeferredTriggerSaveEvent(relinfo, TRIGGER_EVENT_UPDATE,
trigtuple, newtuple);
heap_freetuple(trigtuple);
}
}
static HeapTuple
GetTupleForTrigger(EState *estate, ResultRelInfo *relinfo,
ItemPointer tid, TupleTableSlot **newSlot)
{
Relation relation = relinfo->ri_RelationDesc;
HeapTupleData tuple;
HeapTuple result;
Buffer buffer;
if (newSlot != NULL)
{
int test;
/*
* mark tuple for update
*/
*newSlot = NULL;
tuple.t_self = *tid;
ltrmark:;
test = heap_mark4update(relation, &tuple, &buffer,
GetCurrentCommandId());
switch (test)
{
case HeapTupleSelfUpdated:
ReleaseBuffer(buffer);
return (NULL);
case HeapTupleMayBeUpdated:
break;
case HeapTupleUpdated:
ReleaseBuffer(buffer);
if (XactIsoLevel == XACT_SERIALIZABLE)
elog(ERROR, "Can't serialize access due to concurrent update");
else if (!(ItemPointerEquals(&(tuple.t_self), tid)))
{
TupleTableSlot *epqslot = EvalPlanQual(estate,
relinfo->ri_RangeTableIndex,
&(tuple.t_self));
if (!(TupIsNull(epqslot)))
{
*tid = tuple.t_self;
*newSlot = epqslot;
goto ltrmark;
}
}
/*
* if tuple was deleted or PlanQual failed for updated
* tuple - we have not process this tuple!
*/
return (NULL);
default:
ReleaseBuffer(buffer);
elog(ERROR, "Unknown status %u from heap_mark4update", test);
return (NULL);
}
}
else
{
PageHeader dp;
ItemId lp;
buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(tid));
if (!BufferIsValid(buffer))
elog(ERROR, "GetTupleForTrigger: failed ReadBuffer");
dp = (PageHeader) BufferGetPage(buffer);
lp = PageGetItemId(dp, ItemPointerGetOffsetNumber(tid));
Assert(ItemIdIsUsed(lp));
tuple.t_datamcxt = NULL;
tuple.t_data = (HeapTupleHeader) PageGetItem((Page) dp, lp);
tuple.t_len = ItemIdGetLength(lp);
tuple.t_self = *tid;
}
result = heap_copytuple(&tuple);
ReleaseBuffer(buffer);
return result;
}
/* ----------
* Deferred trigger stuff
* ----------
*/
/* ----------
* Internal data to the deferred trigger mechanism is held
* during entire session in a global context created at startup and
* over statements/commands in a separate context which
* is created at transaction start and destroyed at transaction end.
* ----------
*/
static MemoryContext deftrig_gcxt = NULL;
static MemoryContext deftrig_cxt = NULL;
/* ----------
* Global data that tells which triggers are actually in
* state IMMEDIATE or DEFERRED.
* ----------
*/
static bool deftrig_dfl_all_isset = false;
static bool deftrig_dfl_all_isdeferred = false;
static List *deftrig_dfl_trigstates = NIL;
static bool deftrig_all_isset;
static bool deftrig_all_isdeferred;
static List *deftrig_trigstates;
/* ----------
* The list of pending deferred trigger events during the current transaction.
*
* deftrig_events is the head, deftrig_event_tail is the last entry.
* Because this can grow pretty large, we don't use separate List nodes,
* but instead thread the list through the dte_next fields of the member
* nodes. Saves just a few bytes per entry, but that adds up.
*
* XXX Need to be able to shove this data out to a file if it grows too
* large...
* ----------
*/
static DeferredTriggerEvent deftrig_events;
static DeferredTriggerEvent deftrig_event_tail;
/* ----------
* deferredTriggerCheckState()
*
* Returns true if the trigger identified by tgoid is actually
* in state DEFERRED.
* ----------
*/
static bool
deferredTriggerCheckState(Oid tgoid, int32 itemstate)
{
MemoryContext oldcxt;
List *sl;
DeferredTriggerStatus trigstate;
/*
* Not deferrable triggers (i.e. normal AFTER ROW triggers and
* constraints declared NOT DEFERRABLE, the state is allways false.
*/
if ((itemstate & TRIGGER_DEFERRED_DEFERRABLE) == 0)
return false;
/*
* Lookup if we know an individual state for this trigger
*/
foreach(sl, deftrig_trigstates)
{
trigstate = (DeferredTriggerStatus) lfirst(sl);
if (trigstate->dts_tgoid == tgoid)
return trigstate->dts_tgisdeferred;
}
/*
* No individual state known - so if the user issued a SET CONSTRAINT
* ALL ..., we return that instead of the triggers default state.
*/
if (deftrig_all_isset)
return deftrig_all_isdeferred;
/*
* No ALL state known either, remember the default state as the
* current and return that.
*/
oldcxt = MemoryContextSwitchTo(deftrig_cxt);
trigstate = (DeferredTriggerStatus)
palloc(sizeof(DeferredTriggerStatusData));
trigstate->dts_tgoid = tgoid;
trigstate->dts_tgisdeferred =
((itemstate & TRIGGER_DEFERRED_INITDEFERRED) != 0);
deftrig_trigstates = lappend(deftrig_trigstates, trigstate);
MemoryContextSwitchTo(oldcxt);
return trigstate->dts_tgisdeferred;
}
/* ----------
* deferredTriggerAddEvent()
*
* Add a new trigger event to the queue.
* ----------
*/
static void
deferredTriggerAddEvent(DeferredTriggerEvent event)
{
/*
* Since the event list could grow quite long, we keep track of the
* list tail and append there, rather than just doing a stupid
* "lappend". This avoids O(N^2) behavior for large numbers of events.
*/
event->dte_next = NULL;
if (deftrig_event_tail == NULL)
{
/* first list entry */
deftrig_events = event;
deftrig_event_tail = event;
}
else
{
deftrig_event_tail->dte_next = event;
deftrig_event_tail = event;
}
}
/* ----------
* DeferredTriggerExecute()
*
* Fetch the required tuples back from the heap and fire one
* single trigger function.
*
* Frequently, this will be fired many times in a row for triggers of
* a single relation. Therefore, we cache the open relation and provide
* fmgr lookup cache space at the caller level.
*
* event: event currently being fired.
* itemno: item within event currently being fired.
* rel: open relation for event.
* finfo: array of fmgr lookup cache entries (one per trigger of relation).
* per_tuple_context: memory context to call trigger function in.
* ----------
*/
static void
DeferredTriggerExecute(DeferredTriggerEvent event, int itemno,
Relation rel, FmgrInfo *finfo,
MemoryContext per_tuple_context)
{
Oid tgoid = event->dte_item[itemno].dti_tgoid;
TriggerDesc *trigdesc = rel->trigdesc;
TriggerData LocTriggerData;
HeapTupleData oldtuple;
HeapTupleData newtuple;
HeapTuple rettuple;
Buffer oldbuffer;
Buffer newbuffer;
int tgindx;
/*
* Fetch the required OLD and NEW tuples.
*/
if (ItemPointerIsValid(&(event->dte_oldctid)))
{
ItemPointerCopy(&(event->dte_oldctid), &(oldtuple.t_self));
if (!heap_fetch(rel, SnapshotAny, &oldtuple, &oldbuffer, false, NULL))
elog(ERROR, "DeferredTriggerExecute: failed to fetch old tuple");
}
if (ItemPointerIsValid(&(event->dte_newctid)))
{
ItemPointerCopy(&(event->dte_newctid), &(newtuple.t_self));
if (!heap_fetch(rel, SnapshotAny, &newtuple, &newbuffer, false, NULL))
elog(ERROR, "DeferredTriggerExecute: failed to fetch new tuple");
}
/*
* Setup the trigger information
*/
LocTriggerData.type = T_TriggerData;
LocTriggerData.tg_event = (event->dte_event & TRIGGER_EVENT_OPMASK) |
TRIGGER_EVENT_ROW;
LocTriggerData.tg_relation = rel;
LocTriggerData.tg_trigger = NULL;
for (tgindx = 0; tgindx < trigdesc->numtriggers; tgindx++)
{
if (trigdesc->triggers[tgindx].tgoid == tgoid)
{
LocTriggerData.tg_trigger = &(trigdesc->triggers[tgindx]);
break;
}
}
if (LocTriggerData.tg_trigger == NULL)
elog(ERROR, "DeferredTriggerExecute: can't find trigger %u", tgoid);
switch (event->dte_event & TRIGGER_EVENT_OPMASK)
{
case TRIGGER_EVENT_INSERT:
LocTriggerData.tg_trigtuple = &newtuple;
LocTriggerData.tg_newtuple = NULL;
break;
case TRIGGER_EVENT_UPDATE:
LocTriggerData.tg_trigtuple = &oldtuple;
LocTriggerData.tg_newtuple = &newtuple;
break;
case TRIGGER_EVENT_DELETE:
LocTriggerData.tg_trigtuple = &oldtuple;
LocTriggerData.tg_newtuple = NULL;
break;
}
/*
* Call the trigger and throw away an eventually returned updated
* tuple.
*/
rettuple = ExecCallTriggerFunc(&LocTriggerData,
finfo + tgindx,
per_tuple_context);
if (rettuple != NULL && rettuple != &oldtuple && rettuple != &newtuple)
heap_freetuple(rettuple);
/*
* Might have been a referential integrity constraint trigger. Reset
* the snapshot overriding flag.
*/
ReferentialIntegritySnapshotOverride = false;
/*
* Release buffers
*/
if (ItemPointerIsValid(&(event->dte_oldctid)))
ReleaseBuffer(oldbuffer);
if (ItemPointerIsValid(&(event->dte_newctid)))
ReleaseBuffer(newbuffer);
}
/* ----------
* deferredTriggerInvokeEvents()
*
* Scan the event queue for not yet invoked triggers. Check if they
* should be invoked now and do so.
* ----------
*/
static void
deferredTriggerInvokeEvents(bool immediate_only)
{
DeferredTriggerEvent event,
prev_event = NULL;
MemoryContext per_tuple_context;
Relation rel = NULL;
FmgrInfo *finfo = NULL;
/*
* If immediate_only is true, we remove fully-processed events from
* the event queue to recycle space. If immediate_only is false,
* we are going to discard the whole event queue on return anyway,
* so no need to bother with "retail" pfree's.
*
* In a scenario with many commands in a transaction and many
* deferred-to-end-of-transaction triggers, it could get annoying
* to rescan all the deferred triggers at each command end.
* To speed this up, we could remember the actual end of the queue at
* EndQuery and examine only events that are newer. On state changes
* we simply reset the saved position to the beginning of the queue
* and process all events once with the new states.
*/
/* Make a per-tuple memory context for trigger function calls */
per_tuple_context =
AllocSetContextCreate(CurrentMemoryContext,
"DeferredTriggerTupleContext",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
event = deftrig_events;
while (event != NULL)
{
bool still_deferred_ones = false;
DeferredTriggerEvent next_event;
int i;
/*
* Check if event is already completely done.
*/
if (! (event->dte_event & (TRIGGER_DEFERRED_DONE |
TRIGGER_DEFERRED_CANCELED)))
{
MemoryContextReset(per_tuple_context);
/*
* Check each trigger item in the event.
*/
for (i = 0; i < event->dte_n_items; i++)
{
if (event->dte_item[i].dti_state & TRIGGER_DEFERRED_DONE)
continue;
/*
* This trigger item hasn't been called yet. Check if we
* should call it now.
*/
if (immediate_only &&
deferredTriggerCheckState(event->dte_item[i].dti_tgoid,
event->dte_item[i].dti_state))
{
still_deferred_ones = true;
continue;
}
/*
* So let's fire it... but first, open the correct relation
* if this is not the same relation as before.
*/
if (rel == NULL || rel->rd_id != event->dte_relid)
{
if (rel)
heap_close(rel, NoLock);
if (finfo)
pfree(finfo);
/*
* We assume that an appropriate lock is still held by the
* executor, so grab no new lock here.
*/
rel = heap_open(event->dte_relid, NoLock);
/*
* Allocate space to cache fmgr lookup info for triggers
* of this relation.
*/
finfo = (FmgrInfo *)
palloc(rel->trigdesc->numtriggers * sizeof(FmgrInfo));
MemSet(finfo, 0,
rel->trigdesc->numtriggers * sizeof(FmgrInfo));
}
DeferredTriggerExecute(event, i, rel, finfo,
per_tuple_context);
event->dte_item[i].dti_state |= TRIGGER_DEFERRED_DONE;
} /* end loop over items within event */
}
/*
* If it's now completely done, throw it away.
*
* NB: it's possible the trigger calls above added more events to the
* queue, or that calls we will do later will want to add more,
* so we have to be careful about maintaining list validity here.
*/
next_event = event->dte_next;
if (still_deferred_ones)
{
/* Not done, keep in list */
prev_event = event;
}
else
{
/* Done */
if (immediate_only)
{
/* delink it from list and free it */
if (prev_event)
prev_event->dte_next = next_event;
else
deftrig_events = next_event;
pfree(event);
}
else
{
/*
* We will clean up later, but just for paranoia's sake,
* mark the event done.
*/
event->dte_event |= TRIGGER_DEFERRED_DONE;
}
}
event = next_event;
}
/* Update list tail pointer in case we just deleted tail event */
deftrig_event_tail = prev_event;
/* Release working resources */
if (rel)
heap_close(rel, NoLock);
if (finfo)
pfree(finfo);
MemoryContextDelete(per_tuple_context);
}
/* ----------
* DeferredTriggerInit()
*
* Initialize the deferred trigger mechanism. This is called during
* backend startup and is guaranteed to be before the first of all
* transactions.
* ----------
*/
void
DeferredTriggerInit(void)
{
/*
* Since this context will never be reset, give it a minsize of 0.
* This avoids using any memory if the session never stores anything.
*/
deftrig_gcxt = AllocSetContextCreate(TopMemoryContext,
"DeferredTriggerSession",
0,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
}
/* ----------
* DeferredTriggerBeginXact()
*
* Called at transaction start (either BEGIN or implicit for single
* statement outside of transaction block).
* ----------
*/
void
DeferredTriggerBeginXact(void)
{
MemoryContext oldcxt;
List *l;
DeferredTriggerStatus dflstat;
DeferredTriggerStatus stat;
if (deftrig_cxt != NULL)
elog(ERROR,
"DeferredTriggerBeginXact() called while inside transaction");
/*
* Create the per transaction memory context and copy all states from
* the per session context to here. Set the minsize to 0 to avoid
* wasting memory if there is no deferred trigger data.
*/
deftrig_cxt = AllocSetContextCreate(TopTransactionContext,
"DeferredTriggerXact",
0,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
oldcxt = MemoryContextSwitchTo(deftrig_cxt);
deftrig_all_isset = deftrig_dfl_all_isset;
deftrig_all_isdeferred = deftrig_dfl_all_isdeferred;
deftrig_trigstates = NIL;
foreach(l, deftrig_dfl_trigstates)
{
dflstat = (DeferredTriggerStatus) lfirst(l);
stat = (DeferredTriggerStatus)
palloc(sizeof(DeferredTriggerStatusData));
stat->dts_tgoid = dflstat->dts_tgoid;
stat->dts_tgisdeferred = dflstat->dts_tgisdeferred;
deftrig_trigstates = lappend(deftrig_trigstates, stat);
}
MemoryContextSwitchTo(oldcxt);
deftrig_events = NULL;
deftrig_event_tail = NULL;
}
/* ----------
* DeferredTriggerEndQuery()
*
* Called after one query sent down by the user has completely been
* processed. At this time we invoke all outstanding IMMEDIATE triggers.
* ----------
*/
void
DeferredTriggerEndQuery(void)
{
/*
* Ignore call if we aren't in a transaction.
*/
if (deftrig_cxt == NULL)
return;
deferredTriggerInvokeEvents(true);
}
/* ----------
* DeferredTriggerEndXact()
*
* Called just before the current transaction is committed. At this
* time we invoke all DEFERRED triggers and tidy up.
* ----------
*/
void
DeferredTriggerEndXact(void)
{
/*
* Ignore call if we aren't in a transaction.
*/
if (deftrig_cxt == NULL)
return;
deferredTriggerInvokeEvents(false);
MemoryContextDelete(deftrig_cxt);
deftrig_cxt = NULL;
}
/* ----------
* DeferredTriggerAbortXact()
*
* The current transaction has entered the abort state.
* All outstanding triggers are canceled so we simply throw
* away anything we know.
* ----------
*/
void
DeferredTriggerAbortXact(void)
{
/*
* Ignore call if we aren't in a transaction.
*/
if (deftrig_cxt == NULL)
return;
MemoryContextDelete(deftrig_cxt);
deftrig_cxt = NULL;
}
/* ----------
* DeferredTriggerSetState()
*
* Called for the users SET CONSTRAINTS ... utility command.
* ----------
*/
void
DeferredTriggerSetState(ConstraintsSetStmt *stmt)
{
Relation tgrel;
List *l;
List *ls;
List *loid = NIL;
MemoryContext oldcxt;
bool found;
DeferredTriggerStatus state;
/*
* Handle SET CONSTRAINTS ALL ...
*/
if (stmt->constraints == NIL)
{
if (!IsTransactionBlock())
{
/*
* ... outside of a transaction block
*
* Drop all information about individual trigger states per
* session.
*/
l = deftrig_dfl_trigstates;
while (l != NIL)
{
List *next = lnext(l);
pfree(lfirst(l));
pfree(l);
l = next;
}
deftrig_dfl_trigstates = NIL;
/*
* Set the session ALL state to known.
*/
deftrig_dfl_all_isset = true;
deftrig_dfl_all_isdeferred = stmt->deferred;
return;
}
else
{
/*
* ... inside of a transaction block
*
* Drop all information about individual trigger states per
* transaction.
*/
l = deftrig_trigstates;
while (l != NIL)
{
List *next = lnext(l);
pfree(lfirst(l));
pfree(l);
l = next;
}
deftrig_trigstates = NIL;
/*
* Set the per transaction ALL state to known.
*/
deftrig_all_isset = true;
deftrig_all_isdeferred = stmt->deferred;
return;
}
}
/* ----------
* Handle SET CONSTRAINTS constraint-name [, ...]
* First lookup all trigger Oid's for the constraint names.
* ----------
*/
tgrel = heap_openr(TriggerRelationName, AccessShareLock);
foreach(l, stmt->constraints)
{
char *cname = strVal(lfirst(l));
ScanKeyData skey;
SysScanDesc tgscan;
HeapTuple htup;
/*
* Check that only named constraints are set explicitly
*/
if (strlen(cname) == 0)
elog(ERROR, "unnamed constraints cannot be set explicitly");
/*
* Setup to scan pg_trigger by tgconstrname ...
*/
ScanKeyEntryInitialize(&skey,
(bits16) 0x0,
(AttrNumber) Anum_pg_trigger_tgconstrname,
(RegProcedure) F_NAMEEQ,
PointerGetDatum(cname));
tgscan = systable_beginscan(tgrel, TriggerConstrNameIndex, true,
SnapshotNow, 1, &skey);
/*
* ... and search for the constraint trigger row
*/
found = false;
while (HeapTupleIsValid(htup = systable_getnext(tgscan)))
{
Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(htup);
Oid constr_oid;
/*
* If we found some, check that they fit the deferrability but
* skip ON <event> RESTRICT ones, since they are silently
* never deferrable.
*/
if (stmt->deferred && !pg_trigger->tgdeferrable &&
pg_trigger->tgfoid != F_RI_FKEY_RESTRICT_UPD &&
pg_trigger->tgfoid != F_RI_FKEY_RESTRICT_DEL)
elog(ERROR, "Constraint '%s' is not deferrable",
cname);
constr_oid = htup->t_data->t_oid;
loid = lappendi(loid, constr_oid);
found = true;
}
systable_endscan(tgscan);
/*
* Not found ?
*/
if (!found)
elog(ERROR, "Constraint '%s' does not exist", cname);
}
heap_close(tgrel, AccessShareLock);
if (!IsTransactionBlock())
{
/*
* Outside of a transaction block set the trigger states of
* individual triggers on session level.
*/
oldcxt = MemoryContextSwitchTo(deftrig_gcxt);
foreach(l, loid)
{
found = false;
foreach(ls, deftrig_dfl_trigstates)
{
state = (DeferredTriggerStatus) lfirst(ls);
if (state->dts_tgoid == (Oid) lfirsti(l))
{
state->dts_tgisdeferred = stmt->deferred;
found = true;
break;
}
}
if (!found)
{
state = (DeferredTriggerStatus)
palloc(sizeof(DeferredTriggerStatusData));
state->dts_tgoid = (Oid) lfirsti(l);
state->dts_tgisdeferred = stmt->deferred;
deftrig_dfl_trigstates =
lappend(deftrig_dfl_trigstates, state);
}
}
MemoryContextSwitchTo(oldcxt);
return;
}
else
{
/*
* Inside of a transaction block set the trigger states of
* individual triggers on transaction level.
*/
oldcxt = MemoryContextSwitchTo(deftrig_cxt);
foreach(l, loid)
{
found = false;
foreach(ls, deftrig_trigstates)
{
state = (DeferredTriggerStatus) lfirst(ls);
if (state->dts_tgoid == (Oid) lfirsti(l))
{
state->dts_tgisdeferred = stmt->deferred;
found = true;
break;
}
}
if (!found)
{
state = (DeferredTriggerStatus)
palloc(sizeof(DeferredTriggerStatusData));
state->dts_tgoid = (Oid) lfirsti(l);
state->dts_tgisdeferred = stmt->deferred;
deftrig_trigstates =
lappend(deftrig_trigstates, state);
}
}
MemoryContextSwitchTo(oldcxt);
return;
}
}
/* ----------
* DeferredTriggerSaveEvent()
*
* Called by ExecAR...Triggers() to add the event to the queue.
*
* NOTE: should be called only if we've determined that an event must
* be added to the queue.
* ----------
*/
static void
DeferredTriggerSaveEvent(ResultRelInfo *relinfo, int event,
HeapTuple oldtup, HeapTuple newtup)
{
Relation rel = relinfo->ri_RelationDesc;
TriggerDesc *trigdesc = relinfo->ri_TrigDesc;
MemoryContext oldcxt;
DeferredTriggerEvent new_event;
int new_size;
int i;
int ntriggers;
int *tgindx;
ItemPointerData oldctid;
ItemPointerData newctid;
TriggerData LocTriggerData;
if (deftrig_cxt == NULL)
elog(ERROR,
"DeferredTriggerSaveEvent() called outside of transaction");
/*
* Get the CTID's of OLD and NEW
*/
if (oldtup != NULL)
ItemPointerCopy(&(oldtup->t_self), &(oldctid));
else
ItemPointerSetInvalid(&(oldctid));
if (newtup != NULL)
ItemPointerCopy(&(newtup->t_self), &(newctid));
else
ItemPointerSetInvalid(&(newctid));
/*
* Create a new event
*/
oldcxt = MemoryContextSwitchTo(deftrig_cxt);
ntriggers = trigdesc->n_after_row[event];
tgindx = trigdesc->tg_after_row[event];
new_size = offsetof(DeferredTriggerEventData, dte_item[0]) +
ntriggers * sizeof(DeferredTriggerEventItem);
new_event = (DeferredTriggerEvent) palloc(new_size);
new_event->dte_next = NULL;
new_event->dte_event = event & TRIGGER_EVENT_OPMASK;
new_event->dte_relid = rel->rd_id;
ItemPointerCopy(&oldctid, &(new_event->dte_oldctid));
ItemPointerCopy(&newctid, &(new_event->dte_newctid));
new_event->dte_n_items = ntriggers;
for (i = 0; i < ntriggers; i++)
{
Trigger *trigger = &trigdesc->triggers[tgindx[i]];
new_event->dte_item[i].dti_tgoid = trigger->tgoid;
new_event->dte_item[i].dti_state =
((trigger->tgdeferrable) ?
TRIGGER_DEFERRED_DEFERRABLE : 0) |
((trigger->tginitdeferred) ?
TRIGGER_DEFERRED_INITDEFERRED : 0) |
((trigdesc->n_before_row[event] > 0) ?
TRIGGER_DEFERRED_HAS_BEFORE : 0);
}
MemoryContextSwitchTo(oldcxt);
switch (event & TRIGGER_EVENT_OPMASK)
{
case TRIGGER_EVENT_INSERT:
/* nothing to do */
break;
case TRIGGER_EVENT_UPDATE:
/*
* Check if one of the referenced keys is changed.
*/
for (i = 0; i < ntriggers; i++)
{
Trigger *trigger = &trigdesc->triggers[tgindx[i]];
bool is_ri_trigger;
bool key_unchanged;
/*
* We are interested in RI_FKEY triggers only.
*/
switch (trigger->tgfoid)
{
case F_RI_FKEY_NOACTION_UPD:
case F_RI_FKEY_CASCADE_UPD:
case F_RI_FKEY_RESTRICT_UPD:
case F_RI_FKEY_SETNULL_UPD:
case F_RI_FKEY_SETDEFAULT_UPD:
is_ri_trigger = true;
break;
default:
is_ri_trigger = false;
break;
}
if (!is_ri_trigger)
continue;
LocTriggerData.type = T_TriggerData;
LocTriggerData.tg_event = TRIGGER_EVENT_UPDATE;
LocTriggerData.tg_relation = rel;
LocTriggerData.tg_trigtuple = oldtup;
LocTriggerData.tg_newtuple = newtup;
LocTriggerData.tg_trigger = trigger;
key_unchanged = RI_FKey_keyequal_upd(&LocTriggerData);
if (key_unchanged)
{
/*
* The key hasn't changed, so no need later to invoke
* the trigger at all.
*/
new_event->dte_item[i].dti_state |= TRIGGER_DEFERRED_DONE;
}
}
break;
case TRIGGER_EVENT_DELETE:
/* nothing to do */
break;
}
/*
* Add the new event to the queue.
*/
deferredTriggerAddEvent(new_event);
}
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