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9f2ee8f287
postgresql/src/include/commands/trigger.h
Tom Lane 9f2ee8f287 Re-implement EvalPlanQual processing to improve its performance and eliminate 
a lot of strange behaviors that occurred in join cases.  We now identify the
"current" row for every joined relation in UPDATE, DELETE, and SELECT FOR
UPDATE/SHARE queries.  If an EvalPlanQual recheck is necessary, we jam the
appropriate row into each scan node in the rechecking plan, forcing it to emit
only that one row.  The former behavior could rescan the whole of each joined
relation for each recheck, which was terrible for performance, and what's much
worse could result in duplicated output tuples.

Also, the original implementation of EvalPlanQual could not re-use the recheck
execution tree --- it had to go through a full executor init and shutdown for
every row to be tested.  To avoid this overhead, I've associated a special
runtime Param with each LockRows or ModifyTable plan node, and arranged to
make every scan node below such a node depend on that Param.  Thus, by
signaling a change in that Param, the EPQ machinery can just rescan the
already-built test plan.

This patch also adds a prohibition on set-returning functions in the
targetlist of SELECT FOR UPDATE/SHARE.  This is needed to avoid the
duplicate-output-tuple problem.  It seems fairly reasonable since the
other restrictions on SELECT FOR UPDATE are meant to ensure that there
is a unique correspondence between source tuples and result tuples,
which an output SRF destroys as much as anything else does.
2009-10-26 02:26:45 +00:00

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/*-------------------------------------------------------------------------
*
* trigger.h
* Declarations for trigger handling.
*
* Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/commands/trigger.h,v 1.77 2009/10/26 02:26:41 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef TRIGGER_H
#define TRIGGER_H
#include "nodes/execnodes.h"
#include "nodes/parsenodes.h"
/*
* TriggerData is the node type that is passed as fmgr "context" info
* when a function is called by the trigger manager.
*/
#define CALLED_AS_TRIGGER(fcinfo) \
((fcinfo)->context != NULL && IsA((fcinfo)->context, TriggerData))
typedef uint32 TriggerEvent;
typedef struct TriggerData
{
NodeTag type;
TriggerEvent tg_event;
Relation tg_relation;
HeapTuple tg_trigtuple;
HeapTuple tg_newtuple;
Trigger *tg_trigger;
Buffer tg_trigtuplebuf;
Buffer tg_newtuplebuf;
} TriggerData;
/*
* TriggerEvent bit flags
*
* Note that we assume different event types (INSERT/DELETE/UPDATE/TRUNCATE)
* can't be OR'd together in a single TriggerEvent. This is unlike the
* situation for pg_trigger rows, so pg_trigger.tgtype uses a different
* representation!
*/
#define TRIGGER_EVENT_INSERT 0x00000000
#define TRIGGER_EVENT_DELETE 0x00000001
#define TRIGGER_EVENT_UPDATE 0x00000002
#define TRIGGER_EVENT_TRUNCATE 0x00000003
#define TRIGGER_EVENT_OPMASK 0x00000003
#define TRIGGER_EVENT_ROW 0x00000004
#define TRIGGER_EVENT_BEFORE 0x00000008
/* More TriggerEvent flags, used only within trigger.c */
#define AFTER_TRIGGER_DEFERRABLE 0x00000010
#define AFTER_TRIGGER_INITDEFERRED 0x00000020
#define TRIGGER_FIRED_BY_INSERT(event) \
(((TriggerEvent) (event) & TRIGGER_EVENT_OPMASK) == \
TRIGGER_EVENT_INSERT)
#define TRIGGER_FIRED_BY_DELETE(event) \
(((TriggerEvent) (event) & TRIGGER_EVENT_OPMASK) == \
TRIGGER_EVENT_DELETE)
#define TRIGGER_FIRED_BY_UPDATE(event) \
(((TriggerEvent) (event) & TRIGGER_EVENT_OPMASK) == \
TRIGGER_EVENT_UPDATE)
#define TRIGGER_FIRED_BY_TRUNCATE(event) \
(((TriggerEvent) (event) & TRIGGER_EVENT_OPMASK) == \
TRIGGER_EVENT_TRUNCATE)
#define TRIGGER_FIRED_FOR_ROW(event) \
((TriggerEvent) (event) & TRIGGER_EVENT_ROW)
#define TRIGGER_FIRED_FOR_STATEMENT(event) \
(!TRIGGER_FIRED_FOR_ROW (event))
#define TRIGGER_FIRED_BEFORE(event) \
((TriggerEvent) (event) & TRIGGER_EVENT_BEFORE)
#define TRIGGER_FIRED_AFTER(event) \
(!TRIGGER_FIRED_BEFORE (event))
/*
* Definitions for the replication role based firing.
*/
#define SESSION_REPLICATION_ROLE_ORIGIN 0
#define SESSION_REPLICATION_ROLE_REPLICA 1
#define SESSION_REPLICATION_ROLE_LOCAL 2
extern PGDLLIMPORT int SessionReplicationRole;
/*
* States at which a trigger can be fired. These are the
* possible values for pg_trigger.tgenabled.
*/
#define TRIGGER_FIRES_ON_ORIGIN 'O'
#define TRIGGER_FIRES_ALWAYS 'A'
#define TRIGGER_FIRES_ON_REPLICA 'R'
#define TRIGGER_DISABLED 'D'
extern Oid CreateTrigger(CreateTrigStmt *stmt,
Oid constraintOid, Oid indexOid, const char *prefix,
bool checkPermissions);
extern void DropTrigger(Oid relid, const char *trigname,
DropBehavior behavior, bool missing_ok);
extern void RemoveTriggerById(Oid trigOid);
extern void renametrig(Oid relid, const char *oldname, const char *newname);
extern void EnableDisableTrigger(Relation rel, const char *tgname,
char fires_when, bool skip_system);
extern void RelationBuildTriggers(Relation relation);
extern TriggerDesc *CopyTriggerDesc(TriggerDesc *trigdesc);
extern void FreeTriggerDesc(TriggerDesc *trigdesc);
extern void ExecBSInsertTriggers(EState *estate,
ResultRelInfo *relinfo);
extern void ExecASInsertTriggers(EState *estate,
ResultRelInfo *relinfo);
extern HeapTuple ExecBRInsertTriggers(EState *estate,
ResultRelInfo *relinfo,
HeapTuple trigtuple);
extern void ExecARInsertTriggers(EState *estate,
ResultRelInfo *relinfo,
HeapTuple trigtuple,
List *recheckIndexes);
extern void ExecBSDeleteTriggers(EState *estate,
ResultRelInfo *relinfo);
extern void ExecASDeleteTriggers(EState *estate,
ResultRelInfo *relinfo);
extern bool ExecBRDeleteTriggers(EState *estate,
EPQState *epqstate,
ResultRelInfo *relinfo,
ItemPointer tupleid);
extern void ExecARDeleteTriggers(EState *estate,
ResultRelInfo *relinfo,
ItemPointer tupleid);
extern void ExecBSUpdateTriggers(EState *estate,
ResultRelInfo *relinfo);
extern void ExecASUpdateTriggers(EState *estate,
ResultRelInfo *relinfo);
extern HeapTuple ExecBRUpdateTriggers(EState *estate,
EPQState *epqstate,
ResultRelInfo *relinfo,
ItemPointer tupleid,
HeapTuple newtuple);
extern void ExecARUpdateTriggers(EState *estate,
ResultRelInfo *relinfo,
ItemPointer tupleid,
HeapTuple newtuple,
List *recheckIndexes);
extern void ExecBSTruncateTriggers(EState *estate,
ResultRelInfo *relinfo);
extern void ExecASTruncateTriggers(EState *estate,
ResultRelInfo *relinfo);
extern void AfterTriggerBeginXact(void);
extern void AfterTriggerBeginQuery(void);
extern void AfterTriggerEndQuery(EState *estate);
extern void AfterTriggerFireDeferred(void);
extern void AfterTriggerEndXact(bool isCommit);
extern void AfterTriggerBeginSubXact(void);
extern void AfterTriggerEndSubXact(bool isCommit);
extern void AfterTriggerSetState(ConstraintsSetStmt *stmt);
extern bool AfterTriggerPendingOnRel(Oid relid);
/*
* in utils/adt/ri_triggers.c
*/
extern bool RI_FKey_keyequal_upd_pk(Trigger *trigger, Relation pk_rel,
HeapTuple old_row, HeapTuple new_row);
extern bool RI_FKey_keyequal_upd_fk(Trigger *trigger, Relation fk_rel,
HeapTuple old_row, HeapTuple new_row);
extern bool RI_Initial_Check(Trigger *trigger,
Relation fk_rel, Relation pk_rel);
/* result values for RI_FKey_trigger_type: */
#define RI_TRIGGER_PK 1 /* is a trigger on the PK relation */
#define RI_TRIGGER_FK 2 /* is a trigger on the FK relation */
#define RI_TRIGGER_NONE 0 /* is not an RI trigger function */
extern int RI_FKey_trigger_type(Oid tgfoid);
#endif /* TRIGGER_H */
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