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postgresql/src/backend/executor/nodeModifyTable.c

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/*-------------------------------------------------------------------------
*
* nodeModifyTable.c
* routines to handle ModifyTable nodes.
*
* Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/executor/nodeModifyTable.c
*
*-------------------------------------------------------------------------
*/
/* INTERFACE ROUTINES
* ExecInitModifyTable - initialize the ModifyTable node
* ExecModifyTable - retrieve the next tuple from the node
* ExecEndModifyTable - shut down the ModifyTable node
* ExecReScanModifyTable - rescan the ModifyTable node
*
* NOTES
* Each ModifyTable node contains a list of one or more subplans,
* much like an Append node. There is one subplan per result relation.
* The key reason for this is that in an inherited UPDATE command, each
* result relation could have a different schema (more or different
* columns) requiring a different plan tree to produce it. In an
* inherited DELETE, all the subplans should produce the same output
* rowtype, but we might still find that different plans are appropriate
* for different child relations.
*
* If the query specifies RETURNING, then the ModifyTable returns a
* RETURNING tuple after completing each row insert, update, or delete.
* It must be called again to continue the operation. Without RETURNING,
* we just loop within the node until all the work is done, then
* return NULL. This avoids useless call/return overhead.
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "access/xact.h"
#include "commands/trigger.h"
#include "executor/executor.h"
#include "executor/nodeModifyTable.h"
#include "foreign/fdwapi.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "storage/bufmgr.h"
#include "storage/lmgr.h"
#include "utils/builtins.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/tqual.h"
static bool ExecOnConflictUpdate(ModifyTableState *mtstate,
ResultRelInfo *resultRelInfo,
ItemPointer conflictTid,
TupleTableSlot *planSlot,
TupleTableSlot *excludedSlot,
EState *estate,
bool canSetTag,
TupleTableSlot **returning);
/*
* Verify that the tuples to be produced by INSERT or UPDATE match the
* target relation's rowtype
*
* We do this to guard against stale plans. If plan invalidation is
* functioning properly then we should never get a failure here, but better
* safe than sorry. Note that this is called after we have obtained lock
* on the target rel, so the rowtype can't change underneath us.
*
* The plan output is represented by its targetlist, because that makes
* handling the dropped-column case easier.
*/
static void
ExecCheckPlanOutput(Relation resultRel, List *targetList)
{
TupleDesc resultDesc = RelationGetDescr(resultRel);
int attno = 0;
ListCell *lc;
foreach(lc, targetList)
{
TargetEntry *tle = (TargetEntry *) lfirst(lc);
Form_pg_attribute attr;
if (tle->resjunk)
continue; /* ignore junk tlist items */
if (attno >= resultDesc->natts)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("table row type and query-specified row type do not match"),
errdetail("Query has too many columns.")));
attr = resultDesc->attrs[attno++];
if (!attr->attisdropped)
{
/* Normal case: demand type match */
if (exprType((Node *) tle->expr) != attr->atttypid)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("table row type and query-specified row type do not match"),
errdetail("Table has type %s at ordinal position %d, but query expects %s.",
format_type_be(attr->atttypid),
attno,
format_type_be(exprType((Node *) tle->expr)))));
}
else
{
/*
* For a dropped column, we can't check atttypid (it's likely 0).
* In any case the planner has most likely inserted an INT4 null.
* What we insist on is just *some* NULL constant.
*/
if (!IsA(tle->expr, Const) ||
!((Const *) tle->expr)->constisnull)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("table row type and query-specified row type do not match"),
errdetail("Query provides a value for a dropped column at ordinal position %d.",
attno)));
}
}
if (attno != resultDesc->natts)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("table row type and query-specified row type do not match"),
errdetail("Query has too few columns.")));
}
/*
* ExecProcessReturning --- evaluate a RETURNING list
*
* projectReturning: RETURNING projection info for current result rel
* tupleSlot: slot holding tuple actually inserted/updated/deleted
* planSlot: slot holding tuple returned by top subplan node
*
* Returns a slot holding the result tuple
*/
static TupleTableSlot *
ExecProcessReturning(ProjectionInfo *projectReturning,
TupleTableSlot *tupleSlot,
TupleTableSlot *planSlot)
{
ExprContext *econtext = projectReturning->pi_exprContext;
/*
* Reset per-tuple memory context to free any expression evaluation
* storage allocated in the previous cycle.
*/
ResetExprContext(econtext);
/* Make tuple and any needed join variables available to ExecProject */
econtext->ecxt_scantuple = tupleSlot;
econtext->ecxt_outertuple = planSlot;
/* Compute the RETURNING expressions */
return ExecProject(projectReturning, NULL);
}
/*
* ExecCheckHeapTupleVisible -- verify heap tuple is visible
*
* It would not be consistent with guarantees of the higher isolation levels to
* proceed with avoiding insertion (taking speculative insertion's alternative
* path) on the basis of another tuple that is not visible to MVCC snapshot.
* Check for the need to raise a serialization failure, and do so as necessary.
*/
static void
ExecCheckHeapTupleVisible(EState *estate,
HeapTuple tuple,
Buffer buffer)
{
if (!IsolationUsesXactSnapshot())
return;
if (!HeapTupleSatisfiesVisibility(tuple, estate->es_snapshot, buffer))
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent update")));
}
/*
* ExecCheckTIDVisible -- convenience variant of ExecCheckHeapTupleVisible()
*/
static void
ExecCheckTIDVisible(EState *estate,
ResultRelInfo *relinfo,
ItemPointer tid)
{
Relation rel = relinfo->ri_RelationDesc;
Buffer buffer;
HeapTupleData tuple;
/* Redundantly check isolation level */
if (!IsolationUsesXactSnapshot())
return;
tuple.t_self = *tid;
if (!heap_fetch(rel, SnapshotAny, &tuple, &buffer, false, NULL))
elog(ERROR, "failed to fetch conflicting tuple for ON CONFLICT");
ExecCheckHeapTupleVisible(estate, &tuple, buffer);
ReleaseBuffer(buffer);
}
/* ----------------------------------------------------------------
* ExecInsert
*
* For INSERT, we have to insert the tuple into the target relation
* and insert appropriate tuples into the index relations.
*
* Returns RETURNING result if any, otherwise NULL.
* ----------------------------------------------------------------
*/
static TupleTableSlot *
ExecInsert(ModifyTableState *mtstate,
TupleTableSlot *slot,
TupleTableSlot *planSlot,
List *arbiterIndexes,
OnConflictAction onconflict,
EState *estate,
bool canSetTag)
{
HeapTuple tuple;
ResultRelInfo *resultRelInfo;
Relation resultRelationDesc;
Oid newId;
List *recheckIndexes = NIL;
/*
* get the heap tuple out of the tuple table slot, making sure we have a
* writable copy
*/
tuple = ExecMaterializeSlot(slot);
/*
* get information on the (current) result relation
*/
resultRelInfo = estate->es_result_relation_info;
resultRelationDesc = resultRelInfo->ri_RelationDesc;
/*
* If the result relation has OIDs, force the tuple's OID to zero so that
* heap_insert will assign a fresh OID. Usually the OID already will be
* zero at this point, but there are corner cases where the plan tree can
* return a tuple extracted literally from some table with the same
* rowtype.
*
* XXX if we ever wanted to allow users to assign their own OIDs to new
* rows, this'd be the place to do it. For the moment, we make a point of
* doing this before calling triggers, so that a user-supplied trigger
* could hack the OID if desired.
*/
if (resultRelationDesc->rd_rel->relhasoids)
HeapTupleSetOid(tuple, InvalidOid);
/*
* BEFORE ROW INSERT Triggers.
*
* Note: We fire BEFORE ROW TRIGGERS for every attempted insertion in an
* INSERT ... ON CONFLICT statement. We cannot check for constraint
* violations before firing these triggers, because they can change the
* values to insert. Also, they can run arbitrary user-defined code with
* side-effects that we can't cancel by just not inserting the tuple.
*/
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->trig_insert_before_row)
{
slot = ExecBRInsertTriggers(estate, resultRelInfo, slot);
if (slot == NULL) /* "do nothing" */
return NULL;
/* trigger might have changed tuple */
tuple = ExecMaterializeSlot(slot);
}
/* INSTEAD OF ROW INSERT Triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->trig_insert_instead_row)
{
slot = ExecIRInsertTriggers(estate, resultRelInfo, slot);
if (slot == NULL) /* "do nothing" */
return NULL;
/* trigger might have changed tuple */
tuple = ExecMaterializeSlot(slot);
newId = InvalidOid;
}
else if (resultRelInfo->ri_FdwRoutine)
{
/*
* insert into foreign table: let the FDW do it
*/
slot = resultRelInfo->ri_FdwRoutine->ExecForeignInsert(estate,
resultRelInfo,
slot,
planSlot);
if (slot == NULL) /* "do nothing" */
return NULL;
/* FDW might have changed tuple */
tuple = ExecMaterializeSlot(slot);
newId = InvalidOid;
}
else
{
/*
* Constraints might reference the tableoid column, so initialize
* t_tableOid before evaluating them.
*/
tuple->t_tableOid = RelationGetRelid(resultRelationDesc);
/*
* Check any RLS INSERT WITH CHECK policies
*
* ExecWithCheckOptions() will skip any WCOs which are not of the kind
* we are looking for at this point.
*/
if (resultRelInfo->ri_WithCheckOptions != NIL)
ExecWithCheckOptions(WCO_RLS_INSERT_CHECK,
resultRelInfo, slot, estate);
/*
* Check the constraints of the tuple
*/
if (resultRelationDesc->rd_att->constr)
ExecConstraints(resultRelInfo, slot, estate);
if (onconflict != ONCONFLICT_NONE && resultRelInfo->ri_NumIndices > 0)
{
/* Perform a speculative insertion. */
uint32 specToken;
ItemPointerData conflictTid;
bool specConflict;
/*
* Do a non-conclusive check for conflicts first.
*
* We're not holding any locks yet, so this doesn't guarantee that
* the later insert won't conflict. But it avoids leaving behind
* a lot of canceled speculative insertions, if you run a lot of
* INSERT ON CONFLICT statements that do conflict.
*
* We loop back here if we find a conflict below, either during
* the pre-check, or when we re-check after inserting the tuple
* speculatively.
*/
vlock:
specConflict = false;
if (!ExecCheckIndexConstraints(slot, estate, &conflictTid,
arbiterIndexes))
{
/* committed conflict tuple found */
if (onconflict == ONCONFLICT_UPDATE)
{
/*
* In case of ON CONFLICT DO UPDATE, execute the UPDATE
* part. Be prepared to retry if the UPDATE fails because
* of another concurrent UPDATE/DELETE to the conflict
* tuple.
*/
TupleTableSlot *returning = NULL;
if (ExecOnConflictUpdate(mtstate, resultRelInfo,
&conflictTid, planSlot, slot,
estate, canSetTag, &returning))
{
InstrCountFiltered2(&mtstate->ps, 1);
return returning;
}
else
goto vlock;
}
else
{
/*
* In case of ON CONFLICT DO NOTHING, do nothing. However,
* verify that the tuple is visible to the executor's MVCC
* snapshot at higher isolation levels.
*/
Assert(onconflict == ONCONFLICT_NOTHING);
ExecCheckTIDVisible(estate, resultRelInfo, &conflictTid);
InstrCountFiltered2(&mtstate->ps, 1);
return NULL;
}
}
/*
* Before we start insertion proper, acquire our "speculative
* insertion lock". Others can use that to wait for us to decide
* if we're going to go ahead with the insertion, instead of
* waiting for the whole transaction to complete.
*/
specToken = SpeculativeInsertionLockAcquire(GetCurrentTransactionId());
HeapTupleHeaderSetSpeculativeToken(tuple->t_data, specToken);
/* insert the tuple, with the speculative token */
newId = heap_insert(resultRelationDesc, tuple,
estate->es_output_cid,
HEAP_INSERT_SPECULATIVE,
NULL);
/* insert index entries for tuple */
recheckIndexes = ExecInsertIndexTuples(slot, &(tuple->t_self),
estate, true, &specConflict,
arbiterIndexes);
/* adjust the tuple's state accordingly */
if (!specConflict)
heap_finish_speculative(resultRelationDesc, tuple);
else
heap_abort_speculative(resultRelationDesc, tuple);
/*
* Wake up anyone waiting for our decision. They will re-check
* the tuple, see that it's no longer speculative, and wait on our
* XID as if this was a regularly inserted tuple all along. Or if
* we killed the tuple, they will see it's dead, and proceed as if
* the tuple never existed.
*/
SpeculativeInsertionLockRelease(GetCurrentTransactionId());
/*
* If there was a conflict, start from the beginning. We'll do
* the pre-check again, which will now find the conflicting tuple
* (unless it aborts before we get there).
*/
if (specConflict)
{
list_free(recheckIndexes);
goto vlock;
}
/* Since there was no insertion conflict, we're done */
}
else
{
/*
* insert the tuple normally.
*
* Note: heap_insert returns the tid (location) of the new tuple
* in the t_self field.
*/
newId = heap_insert(resultRelationDesc, tuple,
estate->es_output_cid,
0, NULL);
/* insert index entries for tuple */
if (resultRelInfo->ri_NumIndices > 0)
recheckIndexes = ExecInsertIndexTuples(slot, &(tuple->t_self),
estate, false, NULL,
arbiterIndexes);
}
}
if (canSetTag)
{
(estate->es_processed)++;
estate->es_lastoid = newId;
setLastTid(&(tuple->t_self));
}
/* AFTER ROW INSERT Triggers */
ExecARInsertTriggers(estate, resultRelInfo, tuple, recheckIndexes);
list_free(recheckIndexes);
/*
* Check any WITH CHECK OPTION constraints from parent views. We are
* required to do this after testing all constraints and uniqueness
* violations per the SQL spec, so we do it after actually inserting the
* record into the heap and all indexes.
*
* ExecWithCheckOptions will elog(ERROR) if a violation is found, so the
* tuple will never be seen, if it violates the WITH CHECK OPTION.
*
* ExecWithCheckOptions() will skip any WCOs which are not of the kind we
* are looking for at this point.
*/
if (resultRelInfo->ri_WithCheckOptions != NIL)
ExecWithCheckOptions(WCO_VIEW_CHECK, resultRelInfo, slot, estate);
/* Process RETURNING if present */
if (resultRelInfo->ri_projectReturning)
return ExecProcessReturning(resultRelInfo->ri_projectReturning,
slot, planSlot);
return NULL;
}
/* ----------------------------------------------------------------
* ExecDelete
*
* DELETE is like UPDATE, except that we delete the tuple and no
* index modifications are needed.
*
* When deleting from a table, tupleid identifies the tuple to
* delete and oldtuple is NULL. When deleting from a view,
* oldtuple is passed to the INSTEAD OF triggers and identifies
* what to delete, and tupleid is invalid. When deleting from a
* foreign table, tupleid is invalid; the FDW has to figure out
* which row to delete using data from the planSlot. oldtuple is
* passed to foreign table triggers; it is NULL when the foreign
* table has no relevant triggers.
*
* Returns RETURNING result if any, otherwise NULL.
* ----------------------------------------------------------------
*/
static TupleTableSlot *
ExecDelete(ItemPointer tupleid,
HeapTuple oldtuple,
TupleTableSlot *planSlot,
EPQState *epqstate,
EState *estate,
bool canSetTag)
{
ResultRelInfo *resultRelInfo;
Relation resultRelationDesc;
HTSU_Result result;
HeapUpdateFailureData hufd;
TupleTableSlot *slot = NULL;
/*
* get information on the (current) result relation
*/
resultRelInfo = estate->es_result_relation_info;
resultRelationDesc = resultRelInfo->ri_RelationDesc;
/* BEFORE ROW DELETE Triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->trig_delete_before_row)
{
bool dodelete;
dodelete = ExecBRDeleteTriggers(estate, epqstate, resultRelInfo,
tupleid, oldtuple);
if (!dodelete) /* "do nothing" */
return NULL;
}
/* INSTEAD OF ROW DELETE Triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->trig_delete_instead_row)
{
bool dodelete;
Assert(oldtuple != NULL);
dodelete = ExecIRDeleteTriggers(estate, resultRelInfo, oldtuple);
if (!dodelete) /* "do nothing" */
return NULL;
}
else if (resultRelInfo->ri_FdwRoutine)
{
/*
* delete from foreign table: let the FDW do it
*
* We offer the trigger tuple slot as a place to store RETURNING data,
* although the FDW can return some other slot if it wants. Set up
* the slot's tupdesc so the FDW doesn't need to do that for itself.
*/
slot = estate->es_trig_tuple_slot;
if (slot->tts_tupleDescriptor != RelationGetDescr(resultRelationDesc))
ExecSetSlotDescriptor(slot, RelationGetDescr(resultRelationDesc));
slot = resultRelInfo->ri_FdwRoutine->ExecForeignDelete(estate,
resultRelInfo,
slot,
planSlot);
if (slot == NULL) /* "do nothing" */
return NULL;
}
else
{
/*
* delete the tuple
*
* Note: if es_crosscheck_snapshot isn't InvalidSnapshot, we check
* that the row to be deleted is visible to that snapshot, and throw a
* can't-serialize error if not. This is a special-case behavior
* needed for referential integrity updates in transaction-snapshot
* mode transactions.
*/
ldelete:;
result = heap_delete(resultRelationDesc, tupleid,
estate->es_output_cid,
estate->es_crosscheck_snapshot,
true /* wait for commit */ ,
&hufd);
switch (result)
{
case HeapTupleSelfUpdated:
/*
* The target tuple was already updated or deleted by the
* current command, or by a later command in the current
* transaction. The former case is possible in a join DELETE
* where multiple tuples join to the same target tuple. This
* is somewhat questionable, but Postgres has always allowed
* it: we just ignore additional deletion attempts.
*
* The latter case arises if the tuple is modified by a
* command in a BEFORE trigger, or perhaps by a command in a
* volatile function used in the query. In such situations we
* should not ignore the deletion, but it is equally unsafe to
* proceed. We don't want to discard the original DELETE
* while keeping the triggered actions based on its deletion;
* and it would be no better to allow the original DELETE
* while discarding updates that it triggered. The row update
* carries some information that might be important according
* to business rules; so throwing an error is the only safe
* course.
*
* If a trigger actually intends this type of interaction, it
* can re-execute the DELETE and then return NULL to cancel
* the outer delete.
*/
if (hufd.cmax != estate->es_output_cid)
ereport(ERROR,
(errcode(ERRCODE_TRIGGERED_DATA_CHANGE_VIOLATION),
errmsg("tuple to be updated was already modified by an operation triggered by the current command"),
errhint("Consider using an AFTER trigger instead of a BEFORE trigger to propagate changes to other rows.")));
/* Else, already deleted by self; nothing to do */
return NULL;
case HeapTupleMayBeUpdated:
break;
case HeapTupleUpdated:
if (IsolationUsesXactSnapshot())
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent update")));
if (!ItemPointerEquals(tupleid, &hufd.ctid))
{
TupleTableSlot *epqslot;
epqslot = EvalPlanQual(estate,
epqstate,
resultRelationDesc,
resultRelInfo->ri_RangeTableIndex,
LockTupleExclusive,
&hufd.ctid,
hufd.xmax);
if (!TupIsNull(epqslot))
{
*tupleid = hufd.ctid;
goto ldelete;
}
}
/* tuple already deleted; nothing to do */
return NULL;
default:
elog(ERROR, "unrecognized heap_delete status: %u", result);
return NULL;
}
/*
* Note: Normally one would think that we have to delete index tuples
* associated with the heap tuple now...
*
* ... but in POSTGRES, we have no need to do this because VACUUM will
* take care of it later. We can't delete index tuples immediately
* anyway, since the tuple is still visible to other transactions.
*/
}
if (canSetTag)
(estate->es_processed)++;
/* AFTER ROW DELETE Triggers */
ExecARDeleteTriggers(estate, resultRelInfo, tupleid, oldtuple);
/* Process RETURNING if present */
if (resultRelInfo->ri_projectReturning)
{
/*
* We have to put the target tuple into a slot, which means first we
* gotta fetch it. We can use the trigger tuple slot.
*/
TupleTableSlot *rslot;
HeapTupleData deltuple;
Buffer delbuffer;
if (resultRelInfo->ri_FdwRoutine)
{
/* FDW must have provided a slot containing the deleted row */
Assert(!TupIsNull(slot));
delbuffer = InvalidBuffer;
}
else
{
slot = estate->es_trig_tuple_slot;
if (oldtuple != NULL)
{
deltuple = *oldtuple;
delbuffer = InvalidBuffer;
}
else
{
deltuple.t_self = *tupleid;
if (!heap_fetch(resultRelationDesc, SnapshotAny,
&deltuple, &delbuffer, false, NULL))
elog(ERROR, "failed to fetch deleted tuple for DELETE RETURNING");
}
if (slot->tts_tupleDescriptor != RelationGetDescr(resultRelationDesc))
ExecSetSlotDescriptor(slot, RelationGetDescr(resultRelationDesc));
ExecStoreTuple(&deltuple, slot, InvalidBuffer, false);
}
rslot = ExecProcessReturning(resultRelInfo->ri_projectReturning,
slot, planSlot);
/*
* Before releasing the target tuple again, make sure rslot has a
* local copy of any pass-by-reference values.
*/
ExecMaterializeSlot(rslot);
ExecClearTuple(slot);
if (BufferIsValid(delbuffer))
ReleaseBuffer(delbuffer);
return rslot;
}
return NULL;
}
/* ----------------------------------------------------------------
* ExecUpdate
*
* note: we can't run UPDATE queries with transactions
* off because UPDATEs are actually INSERTs and our
* scan will mistakenly loop forever, updating the tuple
* it just inserted.. This should be fixed but until it
* is, we don't want to get stuck in an infinite loop
* which corrupts your database..
*
* When updating a table, tupleid identifies the tuple to
* update and oldtuple is NULL. When updating a view, oldtuple
* is passed to the INSTEAD OF triggers and identifies what to
* update, and tupleid is invalid. When updating a foreign table,
* tupleid is invalid; the FDW has to figure out which row to
* update using data from the planSlot. oldtuple is passed to
* foreign table triggers; it is NULL when the foreign table has
* no relevant triggers.
*
* Returns RETURNING result if any, otherwise NULL.
* ----------------------------------------------------------------
*/
static TupleTableSlot *
ExecUpdate(ItemPointer tupleid,
HeapTuple oldtuple,
TupleTableSlot *slot,
TupleTableSlot *planSlot,
EPQState *epqstate,
EState *estate,
bool canSetTag)
{
HeapTuple tuple;
ResultRelInfo *resultRelInfo;
Relation resultRelationDesc;
HTSU_Result result;
HeapUpdateFailureData hufd;
List *recheckIndexes = NIL;
/*
* abort the operation if not running transactions
*/
if (IsBootstrapProcessingMode())
elog(ERROR, "cannot UPDATE during bootstrap");
/*
* get the heap tuple out of the tuple table slot, making sure we have a
* writable copy
*/
tuple = ExecMaterializeSlot(slot);
/*
* get information on the (current) result relation
*/
resultRelInfo = estate->es_result_relation_info;
resultRelationDesc = resultRelInfo->ri_RelationDesc;
/* BEFORE ROW UPDATE Triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->trig_update_before_row)
{
slot = ExecBRUpdateTriggers(estate, epqstate, resultRelInfo,
tupleid, oldtuple, slot);
if (slot == NULL) /* "do nothing" */
return NULL;
/* trigger might have changed tuple */
tuple = ExecMaterializeSlot(slot);
}
/* INSTEAD OF ROW UPDATE Triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->trig_update_instead_row)
{
slot = ExecIRUpdateTriggers(estate, resultRelInfo,
oldtuple, slot);
if (slot == NULL) /* "do nothing" */
return NULL;
/* trigger might have changed tuple */
tuple = ExecMaterializeSlot(slot);
}
else if (resultRelInfo->ri_FdwRoutine)
{
/*
* update in foreign table: let the FDW do it
*/
slot = resultRelInfo->ri_FdwRoutine->ExecForeignUpdate(estate,
resultRelInfo,
slot,
planSlot);
if (slot == NULL) /* "do nothing" */
return NULL;
/* FDW might have changed tuple */
tuple = ExecMaterializeSlot(slot);
}
else
{
LockTupleMode lockmode;
/*
* Constraints might reference the tableoid column, so initialize
* t_tableOid before evaluating them.
*/
tuple->t_tableOid = RelationGetRelid(resultRelationDesc);
/*
* Check any RLS UPDATE WITH CHECK policies
*
* If we generate a new candidate tuple after EvalPlanQual testing, we
* must loop back here and recheck any RLS policies and constraints.
* (We don't need to redo triggers, however. If there are any BEFORE
* triggers then trigger.c will have done heap_lock_tuple to lock the
* correct tuple, so there's no need to do them again.)
*
* ExecWithCheckOptions() will skip any WCOs which are not of the kind
* we are looking for at this point.
*/
lreplace:;
if (resultRelInfo->ri_WithCheckOptions != NIL)
ExecWithCheckOptions(WCO_RLS_UPDATE_CHECK,
resultRelInfo, slot, estate);
/*
* Check the constraints of the tuple
*/
if (resultRelationDesc->rd_att->constr)
ExecConstraints(resultRelInfo, slot, estate);
/*
* replace the heap tuple
*
* Note: if es_crosscheck_snapshot isn't InvalidSnapshot, we check
* that the row to be updated is visible to that snapshot, and throw a
* can't-serialize error if not. This is a special-case behavior
* needed for referential integrity updates in transaction-snapshot
* mode transactions.
*/
result = heap_update(resultRelationDesc, tupleid, tuple,
estate->es_output_cid,
estate->es_crosscheck_snapshot,
true /* wait for commit */ ,
&hufd, &lockmode);
switch (result)
{
case HeapTupleSelfUpdated:
/*
* The target tuple was already updated or deleted by the
* current command, or by a later command in the current
* transaction. The former case is possible in a join UPDATE
* where multiple tuples join to the same target tuple. This
* is pretty questionable, but Postgres has always allowed it:
* we just execute the first update action and ignore
* additional update attempts.
*
* The latter case arises if the tuple is modified by a
* command in a BEFORE trigger, or perhaps by a command in a
* volatile function used in the query. In such situations we
* should not ignore the update, but it is equally unsafe to
* proceed. We don't want to discard the original UPDATE
* while keeping the triggered actions based on it; and we
* have no principled way to merge this update with the
* previous ones. So throwing an error is the only safe
* course.
*
* If a trigger actually intends this type of interaction, it
* can re-execute the UPDATE (assuming it can figure out how)
* and then return NULL to cancel the outer update.
*/
if (hufd.cmax != estate->es_output_cid)
ereport(ERROR,
(errcode(ERRCODE_TRIGGERED_DATA_CHANGE_VIOLATION),
errmsg("tuple to be updated was already modified by an operation triggered by the current command"),
errhint("Consider using an AFTER trigger instead of a BEFORE trigger to propagate changes to other rows.")));
/* Else, already updated by self; nothing to do */
return NULL;
case HeapTupleMayBeUpdated:
break;
case HeapTupleUpdated:
if (IsolationUsesXactSnapshot())
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent update")));
if (!ItemPointerEquals(tupleid, &hufd.ctid))
{
TupleTableSlot *epqslot;
epqslot = EvalPlanQual(estate,
epqstate,
resultRelationDesc,
resultRelInfo->ri_RangeTableIndex,
lockmode,
&hufd.ctid,
hufd.xmax);
if (!TupIsNull(epqslot))
{
*tupleid = hufd.ctid;
slot = ExecFilterJunk(resultRelInfo->ri_junkFilter, epqslot);
tuple = ExecMaterializeSlot(slot);
goto lreplace;
}
}
/* tuple already deleted; nothing to do */
return NULL;
default:
elog(ERROR, "unrecognized heap_update status: %u", result);
return NULL;
}
/*
* Note: instead of having to update the old index tuples associated
* with the heap tuple, all we do is form and insert new index tuples.
* This is because UPDATEs are actually DELETEs and INSERTs, and index
* tuple deletion is done later by VACUUM (see notes in ExecDelete).
* All we do here is insert new index tuples. -cim 9/27/89
*/
/*
* insert index entries for tuple
*
* Note: heap_update returns the tid (location) of the new tuple in
* the t_self field.
*
* If it's a HOT update, we mustn't insert new index entries.
*/
if (resultRelInfo->ri_NumIndices > 0 && !HeapTupleIsHeapOnly(tuple))
recheckIndexes = ExecInsertIndexTuples(slot, &(tuple->t_self),
estate, false, NULL, NIL);
}
if (canSetTag)
(estate->es_processed)++;
/* AFTER ROW UPDATE Triggers */
ExecARUpdateTriggers(estate, resultRelInfo, tupleid, oldtuple, tuple,
recheckIndexes);
list_free(recheckIndexes);
/*
* Check any WITH CHECK OPTION constraints from parent views. We are
* required to do this after testing all constraints and uniqueness
* violations per the SQL spec, so we do it after actually updating the
* record in the heap and all indexes.
*
* ExecWithCheckOptions() will skip any WCOs which are not of the kind we
* are looking for at this point.
*/
if (resultRelInfo->ri_WithCheckOptions != NIL)
ExecWithCheckOptions(WCO_VIEW_CHECK, resultRelInfo, slot, estate);
/* Process RETURNING if present */
if (resultRelInfo->ri_projectReturning)
return ExecProcessReturning(resultRelInfo->ri_projectReturning,
slot, planSlot);
return NULL;
}
/*
* ExecOnConflictUpdate --- execute UPDATE of INSERT ON CONFLICT DO UPDATE
*
* Try to lock tuple for update as part of speculative insertion. If
* a qual originating from ON CONFLICT DO UPDATE is satisfied, update
* (but still lock row, even though it may not satisfy estate's
* snapshot).
*
* Returns true if if we're done (with or without an update), or false if
* the caller must retry the INSERT from scratch.
*/
static bool
ExecOnConflictUpdate(ModifyTableState *mtstate,
ResultRelInfo *resultRelInfo,
ItemPointer conflictTid,
TupleTableSlot *planSlot,
TupleTableSlot *excludedSlot,
EState *estate,
bool canSetTag,
TupleTableSlot **returning)
{
ExprContext *econtext = mtstate->ps.ps_ExprContext;
Relation relation = resultRelInfo->ri_RelationDesc;
List *onConflictSetWhere = resultRelInfo->ri_onConflictSetWhere;
HeapTupleData tuple;
HeapUpdateFailureData hufd;
LockTupleMode lockmode;
HTSU_Result test;
Buffer buffer;
/* Determine lock mode to use */
lockmode = ExecUpdateLockMode(estate, resultRelInfo);
/*
* Lock tuple for update. Don't follow updates when tuple cannot be
* locked without doing so. A row locking conflict here means our
* previous conclusion that the tuple is conclusively committed is not
* true anymore.
*/
tuple.t_self = *conflictTid;
test = heap_lock_tuple(relation, &tuple, estate->es_output_cid,
lockmode, LockWaitBlock, false, &buffer,
&hufd);
switch (test)
{
case HeapTupleMayBeUpdated:
/* success! */
break;
case HeapTupleInvisible:
/*
* This can occur when a just inserted tuple is updated again in
* the same command. E.g. because multiple rows with the same
* conflicting key values are inserted.
*
* This is somewhat similar to the ExecUpdate()
* HeapTupleSelfUpdated case. We do not want to proceed because
* it would lead to the same row being updated a second time in
* some unspecified order, and in contrast to plain UPDATEs
* there's no historical behavior to break.
*
* It is the user's responsibility to prevent this situation from
* occurring. These problems are why SQL-2003 similarly specifies
* that for SQL MERGE, an exception must be raised in the event of
* an attempt to update the same row twice.
*/
if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tuple.t_data)))
ereport(ERROR,
(errcode(ERRCODE_CARDINALITY_VIOLATION),
errmsg("ON CONFLICT DO UPDATE command cannot affect row a second time"),
errhint("Ensure that no rows proposed for insertion within the same command have duplicate constrained values.")));
/* This shouldn't happen */
elog(ERROR, "attempted to lock invisible tuple");
case HeapTupleSelfUpdated:
/*
* This state should never be reached. As a dirty snapshot is used
* to find conflicting tuples, speculative insertion wouldn't have
* seen this row to conflict with.
*/
elog(ERROR, "unexpected self-updated tuple");
case HeapTupleUpdated:
if (IsolationUsesXactSnapshot())
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent update")));
/*
* Tell caller to try again from the very start.
*
* It does not make sense to use the usual EvalPlanQual() style
* loop here, as the new version of the row might not conflict
* anymore, or the conflicting tuple has actually been deleted.
*/
ReleaseBuffer(buffer);
return false;
default:
elog(ERROR, "unrecognized heap_lock_tuple status: %u", test);
}
/*
* Success, the tuple is locked.
*
* Reset per-tuple memory context to free any expression evaluation
* storage allocated in the previous cycle.
*/
ResetExprContext(econtext);
/*
* Verify that the tuple is visible to our MVCC snapshot if the current
* isolation level mandates that.
*
* It's not sufficient to rely on the check within ExecUpdate() as e.g.
* CONFLICT ... WHERE clause may prevent us from reaching that.
*
* This means we only ever continue when a new command in the current
* transaction could see the row, even though in READ COMMITTED mode the
* tuple will not be visible according to the current statement's
* snapshot. This is in line with the way UPDATE deals with newer tuple
* versions.
*/
ExecCheckHeapTupleVisible(estate, &tuple, buffer);
/* Store target's existing tuple in the state's dedicated slot */
ExecStoreTuple(&tuple, mtstate->mt_existing, buffer, false);
/*
* Make tuple and any needed join variables available to ExecQual and
* ExecProject. The EXCLUDED tuple is installed in ecxt_innertuple, while
* the target's existing tuple is installed in the scantuple. EXCLUDED
* has been made to reference INNER_VAR in setrefs.c, but there is no
* other redirection.
*/
econtext->ecxt_scantuple = mtstate->mt_existing;
econtext->ecxt_innertuple = excludedSlot;
econtext->ecxt_outertuple = NULL;
if (!ExecQual(onConflictSetWhere, econtext, false))
{
ReleaseBuffer(buffer);
InstrCountFiltered1(&mtstate->ps, 1);
return true; /* done with the tuple */
}
if (resultRelInfo->ri_WithCheckOptions != NIL)
{
/*
* Check target's existing tuple against UPDATE-applicable USING
* security barrier quals (if any), enforced here as RLS checks/WCOs.
*
* The rewriter creates UPDATE RLS checks/WCOs for UPDATE security
* quals, and stores them as WCOs of "kind" WCO_RLS_CONFLICT_CHECK,
* but that's almost the extent of its special handling for ON
* CONFLICT DO UPDATE.
*
* The rewriter will also have associated UPDATE applicable straight
* RLS checks/WCOs for the benefit of the ExecUpdate() call that
* follows. INSERTs and UPDATEs naturally have mutually exclusive WCO
* kinds, so there is no danger of spurious over-enforcement in the
* INSERT or UPDATE path.
*/
ExecWithCheckOptions(WCO_RLS_CONFLICT_CHECK, resultRelInfo,
mtstate->mt_existing,
mtstate->ps.state);
}
/* Project the new tuple version */
ExecProject(resultRelInfo->ri_onConflictSetProj, NULL);
/*
* Note that it is possible that the target tuple has been modified in
* this session, after the above heap_lock_tuple. We choose to not error
* out in that case, in line with ExecUpdate's treatment of similar
* cases. This can happen if an UPDATE is triggered from within
* ExecQual(), ExecWithCheckOptions() or ExecProject() above, e.g. by
* selecting from a wCTE in the ON CONFLICT's SET.
*/
/* Execute UPDATE with projection */
*returning = ExecUpdate(&tuple.t_self, NULL,
mtstate->mt_conflproj, planSlot,
&mtstate->mt_epqstate, mtstate->ps.state,
canSetTag);
ReleaseBuffer(buffer);
return true;
}
/*
* Process BEFORE EACH STATEMENT triggers
*/
static void
fireBSTriggers(ModifyTableState *node)
{
switch (node->operation)
{
case CMD_INSERT:
ExecBSInsertTriggers(node->ps.state, node->resultRelInfo);
if (node->mt_onconflict == ONCONFLICT_UPDATE)
ExecBSUpdateTriggers(node->ps.state,
node->resultRelInfo);
break;
case CMD_UPDATE:
ExecBSUpdateTriggers(node->ps.state, node->resultRelInfo);
break;
case CMD_DELETE:
ExecBSDeleteTriggers(node->ps.state, node->resultRelInfo);
break;
default:
elog(ERROR, "unknown operation");
break;
}
}
/*
* Process AFTER EACH STATEMENT triggers
*/
static void
fireASTriggers(ModifyTableState *node)
{
switch (node->operation)
{
case CMD_INSERT:
if (node->mt_onconflict == ONCONFLICT_UPDATE)
ExecASUpdateTriggers(node->ps.state,
node->resultRelInfo);
ExecASInsertTriggers(node->ps.state, node->resultRelInfo);
break;
case CMD_UPDATE:
ExecASUpdateTriggers(node->ps.state, node->resultRelInfo);
break;
case CMD_DELETE:
ExecASDeleteTriggers(node->ps.state, node->resultRelInfo);
break;
default:
elog(ERROR, "unknown operation");
break;
}
}
/* ----------------------------------------------------------------
* ExecModifyTable
*
* Perform table modifications as required, and return RETURNING results
* if needed.
* ----------------------------------------------------------------
*/
TupleTableSlot *
ExecModifyTable(ModifyTableState *node)
{
EState *estate = node->ps.state;
CmdType operation = node->operation;
ResultRelInfo *saved_resultRelInfo;
ResultRelInfo *resultRelInfo;
PlanState *subplanstate;
JunkFilter *junkfilter;
TupleTableSlot *slot;
TupleTableSlot *planSlot;
ItemPointer tupleid = NULL;
ItemPointerData tuple_ctid;
HeapTupleData oldtupdata;
HeapTuple oldtuple;
/*
* This should NOT get called during EvalPlanQual; we should have passed a
* subplan tree to EvalPlanQual, instead. Use a runtime test not just
* Assert because this condition is easy to miss in testing. (Note:
* although ModifyTable should not get executed within an EvalPlanQual
* operation, we do have to allow it to be initialized and shut down in
* case it is within a CTE subplan. Hence this test must be here, not in
* ExecInitModifyTable.)
*/
if (estate->es_epqTuple != NULL)
elog(ERROR, "ModifyTable should not be called during EvalPlanQual");
/*
* If we've already completed processing, don't try to do more. We need
* this test because ExecPostprocessPlan might call us an extra time, and
* our subplan's nodes aren't necessarily robust against being called
* extra times.
*/
if (node->mt_done)
return NULL;
/*
* On first call, fire BEFORE STATEMENT triggers before proceeding.
*/
if (node->fireBSTriggers)
{
fireBSTriggers(node);
node->fireBSTriggers = false;
}
/* Preload local variables */
resultRelInfo = node->resultRelInfo + node->mt_whichplan;
subplanstate = node->mt_plans[node->mt_whichplan];
junkfilter = resultRelInfo->ri_junkFilter;
/*
* es_result_relation_info must point to the currently active result
* relation while we are within this ModifyTable node. Even though
* ModifyTable nodes can't be nested statically, they can be nested
* dynamically (since our subplan could include a reference to a modifying
* CTE). So we have to save and restore the caller's value.
*/
saved_resultRelInfo = estate->es_result_relation_info;
estate->es_result_relation_info = resultRelInfo;
/*
* Fetch rows from subplan(s), and execute the required table modification
* for each row.
*/
for (;;)
{
/*
* Reset the per-output-tuple exprcontext. This is needed because
* triggers expect to use that context as workspace. It's a bit ugly
* to do this below the top level of the plan, however. We might need
* to rethink this later.
*/
ResetPerTupleExprContext(estate);
planSlot = ExecProcNode(subplanstate);
if (TupIsNull(planSlot))
{
/* advance to next subplan if any */
node->mt_whichplan++;
if (node->mt_whichplan < node->mt_nplans)
{
resultRelInfo++;
subplanstate = node->mt_plans[node->mt_whichplan];
junkfilter = resultRelInfo->ri_junkFilter;
estate->es_result_relation_info = resultRelInfo;
EvalPlanQualSetPlan(&node->mt_epqstate, subplanstate->plan,
node->mt_arowmarks[node->mt_whichplan]);
continue;
}
else
break;
}
EvalPlanQualSetSlot(&node->mt_epqstate, planSlot);
slot = planSlot;
oldtuple = NULL;
if (junkfilter != NULL)
{
/*
* extract the 'ctid' or 'wholerow' junk attribute.
*/
if (operation == CMD_UPDATE || operation == CMD_DELETE)
{
char relkind;
Datum datum;
bool isNull;
relkind = resultRelInfo->ri_RelationDesc->rd_rel->relkind;
if (relkind == RELKIND_RELATION || relkind == RELKIND_MATVIEW)
{
datum = ExecGetJunkAttribute(slot,
junkfilter->jf_junkAttNo,
&isNull);
/* shouldn't ever get a null result... */
if (isNull)
elog(ERROR, "ctid is NULL");
tupleid = (ItemPointer) DatumGetPointer(datum);
tuple_ctid = *tupleid; /* be sure we don't free
* ctid!! */
tupleid = &tuple_ctid;
}
/*
* Use the wholerow attribute, when available, to reconstruct
* the old relation tuple.
*
* Foreign table updates have a wholerow attribute when the
* relation has an AFTER ROW trigger. Note that the wholerow
* attribute does not carry system columns. Foreign table
* triggers miss seeing those, except that we know enough here
* to set t_tableOid. Quite separately from this, the FDW may
* fetch its own junk attrs to identify the row.
*
* Other relevant relkinds, currently limited to views, always
* have a wholerow attribute.
*/
else if (AttributeNumberIsValid(junkfilter->jf_junkAttNo))
{
datum = ExecGetJunkAttribute(slot,
junkfilter->jf_junkAttNo,
&isNull);
/* shouldn't ever get a null result... */
if (isNull)
elog(ERROR, "wholerow is NULL");
oldtupdata.t_data = DatumGetHeapTupleHeader(datum);
oldtupdata.t_len =
HeapTupleHeaderGetDatumLength(oldtupdata.t_data);
ItemPointerSetInvalid(&(oldtupdata.t_self));
/* Historically, view triggers see invalid t_tableOid. */
oldtupdata.t_tableOid =
(relkind == RELKIND_VIEW) ? InvalidOid :
RelationGetRelid(resultRelInfo->ri_RelationDesc);
oldtuple = &oldtupdata;
}
else
Assert(relkind == RELKIND_FOREIGN_TABLE);
}
/*
* apply the junkfilter if needed.
*/
if (operation != CMD_DELETE)
slot = ExecFilterJunk(junkfilter, slot);
}
switch (operation)
{
case CMD_INSERT:
slot = ExecInsert(node, slot, planSlot,
node->mt_arbiterindexes, node->mt_onconflict,
estate, node->canSetTag);
break;
case CMD_UPDATE:
slot = ExecUpdate(tupleid, oldtuple, slot, planSlot,
&node->mt_epqstate, estate, node->canSetTag);
break;
case CMD_DELETE:
slot = ExecDelete(tupleid, oldtuple, planSlot,
&node->mt_epqstate, estate, node->canSetTag);
break;
default:
elog(ERROR, "unknown operation");
break;
}
/*
* If we got a RETURNING result, return it to caller. We'll continue
* the work on next call.
*/
if (slot)
{
estate->es_result_relation_info = saved_resultRelInfo;
return slot;
}
}
/* Restore es_result_relation_info before exiting */
estate->es_result_relation_info = saved_resultRelInfo;
/*
* We're done, but fire AFTER STATEMENT triggers before exiting.
*/
fireASTriggers(node);
node->mt_done = true;
return NULL;
}
/* ----------------------------------------------------------------
* ExecInitModifyTable
* ----------------------------------------------------------------
*/
ModifyTableState *
ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
{
ModifyTableState *mtstate;
CmdType operation = node->operation;
int nplans = list_length(node->plans);
ResultRelInfo *saved_resultRelInfo;
ResultRelInfo *resultRelInfo;
TupleDesc tupDesc;
Plan *subplan;
ListCell *l;
int i;
/* check for unsupported flags */
Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
/*
* create state structure
*/
mtstate = makeNode(ModifyTableState);
mtstate->ps.plan = (Plan *) node;
mtstate->ps.state = estate;
mtstate->ps.targetlist = NIL; /* not actually used */
mtstate->operation = operation;
mtstate->canSetTag = node->canSetTag;
mtstate->mt_done = false;
mtstate->mt_plans = (PlanState **) palloc0(sizeof(PlanState *) * nplans);
mtstate->resultRelInfo = estate->es_result_relations + node->resultRelIndex;
mtstate->mt_arowmarks = (List **) palloc0(sizeof(List *) * nplans);
mtstate->mt_nplans = nplans;
mtstate->mt_onconflict = node->onConflictAction;
mtstate->mt_arbiterindexes = node->arbiterIndexes;
/* set up epqstate with dummy subplan data for the moment */
EvalPlanQualInit(&mtstate->mt_epqstate, estate, NULL, NIL, node->epqParam);
mtstate->fireBSTriggers = true;
/*
* call ExecInitNode on each of the plans to be executed and save the
* results into the array "mt_plans". This is also a convenient place to
* verify that the proposed target relations are valid and open their
* indexes for insertion of new index entries. Note we *must* set
* estate->es_result_relation_info correctly while we initialize each
* sub-plan; ExecContextForcesOids depends on that!
*/
saved_resultRelInfo = estate->es_result_relation_info;
resultRelInfo = mtstate->resultRelInfo;
i = 0;
foreach(l, node->plans)
{
subplan = (Plan *) lfirst(l);
/*
* Verify result relation is a valid target for the current operation
*/
CheckValidResultRel(resultRelInfo->ri_RelationDesc, operation);
/*
* If there are indices on the result relation, open them and save
* descriptors in the result relation info, so that we can add new
* index entries for the tuples we add/update. We need not do this
* for a DELETE, however, since deletion doesn't affect indexes. Also,
* inside an EvalPlanQual operation, the indexes might be open
* already, since we share the resultrel state with the original
* query.
*/
if (resultRelInfo->ri_RelationDesc->rd_rel->relhasindex &&
operation != CMD_DELETE &&
resultRelInfo->ri_IndexRelationDescs == NULL)
ExecOpenIndices(resultRelInfo, mtstate->mt_onconflict != ONCONFLICT_NONE);
/* Now init the plan for this result rel */
estate->es_result_relation_info = resultRelInfo;
mtstate->mt_plans[i] = ExecInitNode(subplan, estate, eflags);
/* Also let FDWs init themselves for foreign-table result rels */
if (resultRelInfo->ri_FdwRoutine != NULL &&
resultRelInfo->ri_FdwRoutine->BeginForeignModify != NULL)
{
List *fdw_private = (List *) list_nth(node->fdwPrivLists, i);
resultRelInfo->ri_FdwRoutine->BeginForeignModify(mtstate,
resultRelInfo,
fdw_private,
i,
eflags);
}
resultRelInfo++;
i++;
}
estate->es_result_relation_info = saved_resultRelInfo;
/*
* Initialize any WITH CHECK OPTION constraints if needed.
*/
resultRelInfo = mtstate->resultRelInfo;
i = 0;
foreach(l, node->withCheckOptionLists)
{
List *wcoList = (List *) lfirst(l);
List *wcoExprs = NIL;
ListCell *ll;
foreach(ll, wcoList)
{
WithCheckOption *wco = (WithCheckOption *) lfirst(ll);
ExprState *wcoExpr = ExecInitExpr((Expr *) wco->qual,
mtstate->mt_plans[i]);
wcoExprs = lappend(wcoExprs, wcoExpr);
}
resultRelInfo->ri_WithCheckOptions = wcoList;
resultRelInfo->ri_WithCheckOptionExprs = wcoExprs;
resultRelInfo++;
i++;
}
/*
* Initialize RETURNING projections if needed.
*/
if (node->returningLists)
{
TupleTableSlot *slot;
ExprContext *econtext;
/*
* Initialize result tuple slot and assign its rowtype using the first
* RETURNING list. We assume the rest will look the same.
*/
tupDesc = ExecTypeFromTL((List *) linitial(node->returningLists),
false);
/* Set up a slot for the output of the RETURNING projection(s) */
ExecInitResultTupleSlot(estate, &mtstate->ps);
ExecAssignResultType(&mtstate->ps, tupDesc);
slot = mtstate->ps.ps_ResultTupleSlot;
/* Need an econtext too */
econtext = CreateExprContext(estate);
mtstate->ps.ps_ExprContext = econtext;
/*
* Build a projection for each result rel.
*/
resultRelInfo = mtstate->resultRelInfo;
foreach(l, node->returningLists)
{
List *rlist = (List *) lfirst(l);
List *rliststate;
rliststate = (List *) ExecInitExpr((Expr *) rlist, &mtstate->ps);
resultRelInfo->ri_projectReturning =
ExecBuildProjectionInfo(rliststate, econtext, slot,
resultRelInfo->ri_RelationDesc->rd_att);
resultRelInfo++;
}
}
else
{
/*
* We still must construct a dummy result tuple type, because InitPlan
* expects one (maybe should change that?).
*/
tupDesc = ExecTypeFromTL(NIL, false);
ExecInitResultTupleSlot(estate, &mtstate->ps);
ExecAssignResultType(&mtstate->ps, tupDesc);
mtstate->ps.ps_ExprContext = NULL;
}
/*
* If needed, Initialize target list, projection and qual for ON CONFLICT
* DO UPDATE.
*/
resultRelInfo = mtstate->resultRelInfo;
if (node->onConflictAction == ONCONFLICT_UPDATE)
{
ExprContext *econtext;
ExprState *setexpr;
TupleDesc tupDesc;
/* insert may only have one plan, inheritance is not expanded */
Assert(nplans == 1);
/* already exists if created by RETURNING processing above */
if (mtstate->ps.ps_ExprContext == NULL)
ExecAssignExprContext(estate, &mtstate->ps);
econtext = mtstate->ps.ps_ExprContext;
/* initialize slot for the existing tuple */
mtstate->mt_existing = ExecInitExtraTupleSlot(mtstate->ps.state);
ExecSetSlotDescriptor(mtstate->mt_existing,
resultRelInfo->ri_RelationDesc->rd_att);
/* carried forward solely for the benefit of explain */
mtstate->mt_excludedtlist = node->exclRelTlist;
/* create target slot for UPDATE SET projection */
tupDesc = ExecTypeFromTL((List *) node->onConflictSet,
resultRelInfo->ri_RelationDesc->rd_rel->relhasoids);
mtstate->mt_conflproj = ExecInitExtraTupleSlot(mtstate->ps.state);
ExecSetSlotDescriptor(mtstate->mt_conflproj, tupDesc);
/* build UPDATE SET expression and projection state */
setexpr = ExecInitExpr((Expr *) node->onConflictSet, &mtstate->ps);
resultRelInfo->ri_onConflictSetProj =
ExecBuildProjectionInfo((List *) setexpr, econtext,
mtstate->mt_conflproj,
resultRelInfo->ri_RelationDesc->rd_att);
/* build DO UPDATE WHERE clause expression */
if (node->onConflictWhere)
{
ExprState *qualexpr;
qualexpr = ExecInitExpr((Expr *) node->onConflictWhere,
&mtstate->ps);
resultRelInfo->ri_onConflictSetWhere = (List *) qualexpr;
}
}
/*
* If we have any secondary relations in an UPDATE or DELETE, they need to
* be treated like non-locked relations in SELECT FOR UPDATE, ie, the
* EvalPlanQual mechanism needs to be told about them. Locate the
* relevant ExecRowMarks.
*/
foreach(l, node->rowMarks)
{
PlanRowMark *rc = (PlanRowMark *) lfirst(l);
ExecRowMark *erm;
Assert(IsA(rc, PlanRowMark));
/* ignore "parent" rowmarks; they are irrelevant at runtime */
if (rc->isParent)
continue;
/* find ExecRowMark (same for all subplans) */
erm = ExecFindRowMark(estate, rc->rti, false);
/* build ExecAuxRowMark for each subplan */
for (i = 0; i < nplans; i++)
{
ExecAuxRowMark *aerm;
subplan = mtstate->mt_plans[i]->plan;
aerm = ExecBuildAuxRowMark(erm, subplan->targetlist);
mtstate->mt_arowmarks[i] = lappend(mtstate->mt_arowmarks[i], aerm);
}
}
/* select first subplan */
mtstate->mt_whichplan = 0;
subplan = (Plan *) linitial(node->plans);
EvalPlanQualSetPlan(&mtstate->mt_epqstate, subplan,
mtstate->mt_arowmarks[0]);
/*
* Initialize the junk filter(s) if needed. INSERT queries need a filter
* if there are any junk attrs in the tlist. UPDATE and DELETE always
* need a filter, since there's always a junk 'ctid' or 'wholerow'
* attribute present --- no need to look first.
*
* If there are multiple result relations, each one needs its own junk
* filter. Note multiple rels are only possible for UPDATE/DELETE, so we
* can't be fooled by some needing a filter and some not.
*
* This section of code is also a convenient place to verify that the
* output of an INSERT or UPDATE matches the target table(s).
*/
{
bool junk_filter_needed = false;
switch (operation)
{
case CMD_INSERT:
foreach(l, subplan->targetlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(l);
if (tle->resjunk)
{
junk_filter_needed = true;
break;
}
}
break;
case CMD_UPDATE:
case CMD_DELETE:
junk_filter_needed = true;
break;
default:
elog(ERROR, "unknown operation");
break;
}
if (junk_filter_needed)
{
resultRelInfo = mtstate->resultRelInfo;
for (i = 0; i < nplans; i++)
{
JunkFilter *j;
subplan = mtstate->mt_plans[i]->plan;
if (operation == CMD_INSERT || operation == CMD_UPDATE)
ExecCheckPlanOutput(resultRelInfo->ri_RelationDesc,
subplan->targetlist);
j = ExecInitJunkFilter(subplan->targetlist,
resultRelInfo->ri_RelationDesc->rd_att->tdhasoid,
ExecInitExtraTupleSlot(estate));
if (operation == CMD_UPDATE || operation == CMD_DELETE)
{
/* For UPDATE/DELETE, find the appropriate junk attr now */
char relkind;
relkind = resultRelInfo->ri_RelationDesc->rd_rel->relkind;
if (relkind == RELKIND_RELATION ||
relkind == RELKIND_MATVIEW)
{
j->jf_junkAttNo = ExecFindJunkAttribute(j, "ctid");
if (!AttributeNumberIsValid(j->jf_junkAttNo))
elog(ERROR, "could not find junk ctid column");
}
else if (relkind == RELKIND_FOREIGN_TABLE)
{
/*
* When there is an AFTER trigger, there should be a
* wholerow attribute.
*/
j->jf_junkAttNo = ExecFindJunkAttribute(j, "wholerow");
}
else
{
j->jf_junkAttNo = ExecFindJunkAttribute(j, "wholerow");
if (!AttributeNumberIsValid(j->jf_junkAttNo))
elog(ERROR, "could not find junk wholerow column");
}
}
resultRelInfo->ri_junkFilter = j;
resultRelInfo++;
}
}
else
{
if (operation == CMD_INSERT)
ExecCheckPlanOutput(mtstate->resultRelInfo->ri_RelationDesc,
subplan->targetlist);
}
}
/*
* Set up a tuple table slot for use for trigger output tuples. In a plan
* containing multiple ModifyTable nodes, all can share one such slot, so
* we keep it in the estate.
*/
if (estate->es_trig_tuple_slot == NULL)
estate->es_trig_tuple_slot = ExecInitExtraTupleSlot(estate);
/*
* Lastly, if this is not the primary (canSetTag) ModifyTable node, add it
* to estate->es_auxmodifytables so that it will be run to completion by
* ExecPostprocessPlan. (It'd actually work fine to add the primary
* ModifyTable node too, but there's no need.) Note the use of lcons not
* lappend: we need later-initialized ModifyTable nodes to be shut down
* before earlier ones. This ensures that we don't throw away RETURNING
* rows that need to be seen by a later CTE subplan.
*/
if (!mtstate->canSetTag)
estate->es_auxmodifytables = lcons(mtstate,
estate->es_auxmodifytables);
return mtstate;
}
/* ----------------------------------------------------------------
* ExecEndModifyTable
*
* Shuts down the plan.
*
* Returns nothing of interest.
* ----------------------------------------------------------------
*/
void
ExecEndModifyTable(ModifyTableState *node)
{
int i;
/*
* Allow any FDWs to shut down
*/
for (i = 0; i < node->mt_nplans; i++)
{
ResultRelInfo *resultRelInfo = node->resultRelInfo + i;
if (resultRelInfo->ri_FdwRoutine != NULL &&
resultRelInfo->ri_FdwRoutine->EndForeignModify != NULL)
resultRelInfo->ri_FdwRoutine->EndForeignModify(node->ps.state,
resultRelInfo);
}
/*
* Free the exprcontext
*/
ExecFreeExprContext(&node->ps);
/*
* clean out the tuple table
*/
ExecClearTuple(node->ps.ps_ResultTupleSlot);
/*
* Terminate EPQ execution if active
*/
EvalPlanQualEnd(&node->mt_epqstate);
/*
* shut down subplans
*/
for (i = 0; i < node->mt_nplans; i++)
ExecEndNode(node->mt_plans[i]);
}
void
ExecReScanModifyTable(ModifyTableState *node)
{
/*
* Currently, we don't need to support rescan on ModifyTable nodes. The
* semantics of that would be a bit debatable anyway.
*/
elog(ERROR, "ExecReScanModifyTable is not implemented");
}
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