/*-------------------------------------------------------------------------
*
* nodeModifyTable.c
* routines to handle ModifyTable nodes.
*
* Portions Copyright (c) 1996-2024, 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
* The ModifyTable node receives input from its outerPlan, which is
* the data to insert for INSERT cases, the changed columns' new
* values plus row-locating info for UPDATE and MERGE cases, or just the
* row-locating info for DELETE cases.
*
* The relation to modify can be an ordinary table, a foreign table, or a
* view. If it's a view, either it has sufficient INSTEAD OF triggers or
* this node executes only MERGE ... DO NOTHING. If the original MERGE
* targeted a view not in one of those two categories, earlier processing
* already pointed the ModifyTable result relation to an underlying
* relation of that other view. This node does process
* ri_WithCheckOptions, which may have expressions from those other,
* automatically updatable views.
*
* MERGE runs a join between the source relation and the target table.
* If any WHEN NOT MATCHED [BY TARGET] clauses are present, then the join
* is an outer join that might output tuples without a matching target
* tuple. In this case, any unmatched target tuples will have NULL
* row-locating info, and only INSERT can be run. But for matched target
* tuples, the row-locating info is used to determine the tuple to UPDATE
* or DELETE. When all clauses are WHEN MATCHED or WHEN NOT MATCHED BY
* SOURCE, all tuples produced by the join will include a matching target
* tuple, so all tuples contain row-locating info.
*
* 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/tableam.h"
#include "access/xact.h"
#include "commands/trigger.h"
#include "executor/execPartition.h"
#include "executor/executor.h"
#include "executor/nodeModifyTable.h"
#include "foreign/fdwapi.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/optimizer.h"
#include "rewrite/rewriteHandler.h"
#include "rewrite/rewriteManip.h"
#include "storage/lmgr.h"
#include "utils/builtins.h"
#include "utils/datum.h"
#include "utils/rel.h"
#include "utils/snapmgr.h"
typedef struct MTTargetRelLookup
{
Oid relationOid; /* hash key, must be first */
int relationIndex; /* rel's index in resultRelInfo[] array */
} MTTargetRelLookup;
/*
* Context struct for a ModifyTable operation, containing basic execution
* state and some output variables populated by ExecUpdateAct() and
* ExecDeleteAct() to report the result of their actions to callers.
*/
typedef struct ModifyTableContext
{
/* Operation state */
ModifyTableState *mtstate;
EPQState *epqstate;
EState *estate;
/*
* Slot containing tuple obtained from ModifyTable's subplan. Used to
* access "junk" columns that are not going to be stored.
*/
TupleTableSlot *planSlot;
/*
* Information about the changes that were made concurrently to a tuple
* being updated or deleted
*/
TM_FailureData tmfd;
/*
* The tuple projected by the INSERT's RETURNING clause, when doing a
* cross-partition UPDATE
*/
TupleTableSlot *cpUpdateReturningSlot;
} ModifyTableContext;
/*
* Context struct containing output data specific to UPDATE operations.
*/
typedef struct UpdateContext
{
bool crossPartUpdate; /* was it a cross-partition update? */
TU_UpdateIndexes updateIndexes; /* Which index updates are required? */
/*
* Lock mode to acquire on the latest tuple version before performing
* EvalPlanQual on it
*/
LockTupleMode lockmode;
} UpdateContext;
static void ExecBatchInsert(ModifyTableState *mtstate,
ResultRelInfo *resultRelInfo,
TupleTableSlot **slots,
TupleTableSlot **planSlots,
int numSlots,
EState *estate,
bool canSetTag);
static void ExecPendingInserts(EState *estate);
static void ExecCrossPartitionUpdateForeignKey(ModifyTableContext *context,
ResultRelInfo *sourcePartInfo,
ResultRelInfo *destPartInfo,
ItemPointer tupleid,
TupleTableSlot *oldslot,
TupleTableSlot *newslot);
static bool ExecOnConflictUpdate(ModifyTableContext *context,
ResultRelInfo *resultRelInfo,
ItemPointer conflictTid,
TupleTableSlot *excludedSlot,
bool canSetTag,
TupleTableSlot **returning);
static TupleTableSlot *ExecPrepareTupleRouting(ModifyTableState *mtstate,
EState *estate,
PartitionTupleRouting *proute,
ResultRelInfo *targetRelInfo,
TupleTableSlot *slot,
ResultRelInfo **partRelInfo);
static TupleTableSlot *ExecMerge(ModifyTableContext *context,
ResultRelInfo *resultRelInfo,
ItemPointer tupleid,
HeapTuple oldtuple,
bool canSetTag);
static void ExecInitMerge(ModifyTableState *mtstate, EState *estate);
static TupleTableSlot *ExecMergeMatched(ModifyTableContext *context,
ResultRelInfo *resultRelInfo,
ItemPointer tupleid,
HeapTuple oldtuple,
bool canSetTag,
bool *matched);
static TupleTableSlot *ExecMergeNotMatched(ModifyTableContext *context,
ResultRelInfo *resultRelInfo,
bool canSetTag);
/*
* Verify that the tuples to be produced by INSERT 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.
*
* We used to use this for UPDATE as well, but now the equivalent checks
* are done in ExecBuildUpdateProjection.
*/
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;
Assert(!tle->resjunk); /* caller removed junk items already */
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 = TupleDescAttr(resultDesc, attno);
attno++;
/*
* Special cases here should match planner's expand_insert_targetlist.
*/
if (attr->attisdropped)
{
/*
* 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)));
}
else if (attr->attgenerated)
{
/*
* For a generated column, the planner will have inserted a null
* of the column's base type (to avoid possibly failing on domain
* not-null constraints). It doesn't seem worth insisting on that
* exact type though, since a null value is type-independent. As
* above, just insist on *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 generated column at ordinal position %d.",
attno)));
}
else
{
/* 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)))));
}
}
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
*
* resultRelInfo: current result rel
* tupleSlot: slot holding tuple actually inserted/updated/deleted
* planSlot: slot holding tuple returned by top subplan node
*
* Note: If tupleSlot is NULL, the FDW should have already provided econtext's
* scan tuple.
*
* Returns a slot holding the result tuple
*/
static TupleTableSlot *
ExecProcessReturning(ResultRelInfo *resultRelInfo,
TupleTableSlot *tupleSlot,
TupleTableSlot *planSlot)
{
ProjectionInfo *projectReturning = resultRelInfo->ri_projectReturning;
ExprContext *econtext = projectReturning->pi_exprContext;
/* Make tuple and any needed join variables available to ExecProject */
if (tupleSlot)
econtext->ecxt_scantuple = tupleSlot;
econtext->ecxt_outertuple = planSlot;
/*
* RETURNING expressions might reference the tableoid column, so
* reinitialize tts_tableOid before evaluating them.
*/
econtext->ecxt_scantuple->tts_tableOid =
RelationGetRelid(resultRelInfo->ri_RelationDesc);
/* Compute the RETURNING expressions */
return ExecProject(projectReturning);
}
/*
* ExecCheckTupleVisible -- verify 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
ExecCheckTupleVisible(EState *estate,
Relation rel,
TupleTableSlot *slot)
{
if (!IsolationUsesXactSnapshot())
return;
if (!table_tuple_satisfies_snapshot(rel, slot, estate->es_snapshot))
{
Datum xminDatum;
TransactionId xmin;
bool isnull;
xminDatum = slot_getsysattr(slot, MinTransactionIdAttributeNumber, &isnull);
Assert(!isnull);
xmin = DatumGetTransactionId(xminDatum);
/*
* We should not raise a serialization failure if the conflict is
* against a tuple inserted by our own transaction, even if it's not
* visible to our snapshot. (This would happen, for example, if
* conflicting keys are proposed for insertion in a single command.)
*/
if (!TransactionIdIsCurrentTransactionId(xmin))
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent update")));
}
}
/*
* ExecCheckTIDVisible -- convenience variant of ExecCheckTupleVisible()
*/
static void
ExecCheckTIDVisible(EState *estate,
ResultRelInfo *relinfo,
ItemPointer tid,
TupleTableSlot *tempSlot)
{
Relation rel = relinfo->ri_RelationDesc;
/* Redundantly check isolation level */
if (!IsolationUsesXactSnapshot())
return;
if (!table_tuple_fetch_row_version(rel, tid, SnapshotAny, tempSlot))
elog(ERROR, "failed to fetch conflicting tuple for ON CONFLICT");
ExecCheckTupleVisible(estate, rel, tempSlot);
ExecClearTuple(tempSlot);
}
/*
* Initialize to compute stored generated columns for a tuple
*
* This fills the resultRelInfo's ri_GeneratedExprsI/ri_NumGeneratedNeededI
* or ri_GeneratedExprsU/ri_NumGeneratedNeededU fields, depending on cmdtype.
* If cmdType == CMD_UPDATE, the ri_extraUpdatedCols field is filled too.
*
* Note: usually, a given query would need only one of ri_GeneratedExprsI and
* ri_GeneratedExprsU per result rel; but MERGE can need both, and so can
* cross-partition UPDATEs, since a partition might be the target of both
* UPDATE and INSERT actions.
*/
void
ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
EState *estate,
CmdType cmdtype)
{
Relation rel = resultRelInfo->ri_RelationDesc;
TupleDesc tupdesc = RelationGetDescr(rel);
int natts = tupdesc->natts;
ExprState **ri_GeneratedExprs;
int ri_NumGeneratedNeeded;
Bitmapset *updatedCols;
MemoryContext oldContext;
/* Nothing to do if no generated columns */
if (!(tupdesc->constr && tupdesc->constr->has_generated_stored))
return;
/*
* In an UPDATE, we can skip computing any generated columns that do not
* depend on any UPDATE target column. But if there is a BEFORE ROW
* UPDATE trigger, we cannot skip because the trigger might change more
* columns.
*/
if (cmdtype == CMD_UPDATE &&
!(rel->trigdesc && rel->trigdesc->trig_update_before_row))
updatedCols = ExecGetUpdatedCols(resultRelInfo, estate);
else
updatedCols = NULL;
/*
* Make sure these data structures are built in the per-query memory
* context so they'll survive throughout the query.
*/
oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
ri_GeneratedExprs = (ExprState **) palloc0(natts * sizeof(ExprState *));
ri_NumGeneratedNeeded = 0;
for (int i = 0; i < natts; i++)
{
if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_STORED)
{
Expr *expr;
/* Fetch the GENERATED AS expression tree */
expr = (Expr *) build_column_default(rel, i + 1);
if (expr == NULL)
elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
i + 1, RelationGetRelationName(rel));
/*
* If it's an update with a known set of update target columns,
* see if we can skip the computation.
*/
if (updatedCols)
{
Bitmapset *attrs_used = NULL;
pull_varattnos((Node *) expr, 1, &attrs_used);
if (!bms_overlap(updatedCols, attrs_used))
continue; /* need not update this column */
}
/* No luck, so prepare the expression for execution */
ri_GeneratedExprs[i] = ExecPrepareExpr(expr, estate);
ri_NumGeneratedNeeded++;
/* If UPDATE, mark column in resultRelInfo->ri_extraUpdatedCols */
if (cmdtype == CMD_UPDATE)
resultRelInfo->ri_extraUpdatedCols =
bms_add_member(resultRelInfo->ri_extraUpdatedCols,
i + 1 - FirstLowInvalidHeapAttributeNumber);
}
}
/* Save in appropriate set of fields */
if (cmdtype == CMD_UPDATE)
{
/* Don't call twice */
Assert(resultRelInfo->ri_GeneratedExprsU == NULL);
resultRelInfo->ri_GeneratedExprsU = ri_GeneratedExprs;
resultRelInfo->ri_NumGeneratedNeededU = ri_NumGeneratedNeeded;
}
else
{
/* Don't call twice */
Assert(resultRelInfo->ri_GeneratedExprsI == NULL);
resultRelInfo->ri_GeneratedExprsI = ri_GeneratedExprs;
resultRelInfo->ri_NumGeneratedNeededI = ri_NumGeneratedNeeded;
}
MemoryContextSwitchTo(oldContext);
}
/*
* Compute stored generated columns for a tuple
*/
void
ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
EState *estate, TupleTableSlot *slot,
CmdType cmdtype)
{
Relation rel = resultRelInfo->ri_RelationDesc;
TupleDesc tupdesc = RelationGetDescr(rel);
int natts = tupdesc->natts;
ExprContext *econtext = GetPerTupleExprContext(estate);
ExprState **ri_GeneratedExprs;
MemoryContext oldContext;
Datum *values;
bool *nulls;
/* We should not be called unless this is true */
Assert(tupdesc->constr && tupdesc->constr->has_generated_stored);
/*
* Initialize the expressions if we didn't already, and check whether we
* can exit early because nothing needs to be computed.
*/
if (cmdtype == CMD_UPDATE)
{
if (resultRelInfo->ri_GeneratedExprsU == NULL)
ExecInitStoredGenerated(resultRelInfo, estate, cmdtype);
if (resultRelInfo->ri_NumGeneratedNeededU == 0)
return;
ri_GeneratedExprs = resultRelInfo->ri_GeneratedExprsU;
}
else
{
if (resultRelInfo->ri_GeneratedExprsI == NULL)
ExecInitStoredGenerated(resultRelInfo, estate, cmdtype);
/* Early exit is impossible given the prior Assert */
Assert(resultRelInfo->ri_NumGeneratedNeededI > 0);
ri_GeneratedExprs = resultRelInfo->ri_GeneratedExprsI;
}
oldContext = MemoryContextSwitchTo(GetPerTupleMemoryContext(estate));
values = palloc(sizeof(*values) * natts);
nulls = palloc(sizeof(*nulls) * natts);
slot_getallattrs(slot);
memcpy(nulls, slot->tts_isnull, sizeof(*nulls) * natts);
for (int i = 0; i < natts; i++)
{
Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
if (ri_GeneratedExprs[i])
{
Datum val;
bool isnull;
Assert(attr->attgenerated == ATTRIBUTE_GENERATED_STORED);
econtext->ecxt_scantuple = slot;
val = ExecEvalExpr(ri_GeneratedExprs[i], econtext, &isnull);
/*
* We must make a copy of val as we have no guarantees about where
* memory for a pass-by-reference Datum is located.
*/
if (!isnull)
val = datumCopy(val, attr->attbyval, attr->attlen);
values[i] = val;
nulls[i] = isnull;
}
else
{
if (!nulls[i])
values[i] = datumCopy(slot->tts_values[i], attr->attbyval, attr->attlen);
}
}
ExecClearTuple(slot);
memcpy(slot->tts_values, values, sizeof(*values) * natts);
memcpy(slot->tts_isnull, nulls, sizeof(*nulls) * natts);
ExecStoreVirtualTuple(slot);
ExecMaterializeSlot(slot);
MemoryContextSwitchTo(oldContext);
}
/*
* ExecInitInsertProjection
* Do one-time initialization of projection data for INSERT tuples.
*
* INSERT queries may need a projection to filter out junk attrs in the tlist.
*
* This is also a convenient place to verify that the
* output of an INSERT matches the target table.
*/
static void
ExecInitInsertProjection(ModifyTableState *mtstate,
ResultRelInfo *resultRelInfo)
{
ModifyTable *node = (ModifyTable *) mtstate->ps.plan;
Plan *subplan = outerPlan(node);
EState *estate = mtstate->ps.state;
List *insertTargetList = NIL;
bool need_projection = false;
ListCell *l;
/* Extract non-junk columns of the subplan's result tlist. */
foreach(l, subplan->targetlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(l);
if (!tle->resjunk)
insertTargetList = lappend(insertTargetList, tle);
else
need_projection = true;
}
/*
* The junk-free list must produce a tuple suitable for the result
* relation.
*/
ExecCheckPlanOutput(resultRelInfo->ri_RelationDesc, insertTargetList);
/* We'll need a slot matching the table's format. */
resultRelInfo->ri_newTupleSlot =
table_slot_create(resultRelInfo->ri_RelationDesc,
&estate->es_tupleTable);
/* Build ProjectionInfo if needed (it probably isn't). */
if (need_projection)
{
TupleDesc relDesc = RelationGetDescr(resultRelInfo->ri_RelationDesc);
/* need an expression context to do the projection */
if (mtstate->ps.ps_ExprContext == NULL)
ExecAssignExprContext(estate, &mtstate->ps);
resultRelInfo->ri_projectNew =
ExecBuildProjectionInfo(insertTargetList,
mtstate->ps.ps_ExprContext,
resultRelInfo->ri_newTupleSlot,
&mtstate->ps,
relDesc);
}
resultRelInfo->ri_projectNewInfoValid = true;
}
/*
* ExecInitUpdateProjection
* Do one-time initialization of projection data for UPDATE tuples.
*
* UPDATE always needs a projection, because (1) there's always some junk
* attrs, and (2) we may need to merge values of not-updated columns from
* the old tuple into the final tuple. In UPDATE, the tuple arriving from
* the subplan contains only new values for the changed columns, plus row
* identity info in the junk attrs.
*
* This is "one-time" for any given result rel, but we might touch more than
* one result rel in the course of an inherited UPDATE, and each one needs
* its own projection due to possible column order variation.
*
* This is also a convenient place to verify that the output of an UPDATE
* matches the target table (ExecBuildUpdateProjection does that).
*/
static void
ExecInitUpdateProjection(ModifyTableState *mtstate,
ResultRelInfo *resultRelInfo)
{
ModifyTable *node = (ModifyTable *) mtstate->ps.plan;
Plan *subplan = outerPlan(node);
EState *estate = mtstate->ps.state;
TupleDesc relDesc = RelationGetDescr(resultRelInfo->ri_RelationDesc);
int whichrel;
List *updateColnos;
/*
* Usually, mt_lastResultIndex matches the target rel. If it happens not
* to, we can get the index the hard way with an integer division.
*/
whichrel = mtstate->mt_lastResultIndex;
if (resultRelInfo != mtstate->resultRelInfo + whichrel)
{
whichrel = resultRelInfo - mtstate->resultRelInfo;
Assert(whichrel >= 0 && whichrel < mtstate->mt_nrels);
}
updateColnos = (List *) list_nth(node->updateColnosLists, whichrel);
/*
* For UPDATE, we use the old tuple to fill up missing values in the tuple
* produced by the subplan to get the new tuple. We need two slots, both
* matching the table's desired format.
*/
resultRelInfo->ri_oldTupleSlot =
table_slot_create(resultRelInfo->ri_RelationDesc,
&estate->es_tupleTable);
resultRelInfo->ri_newTupleSlot =
table_slot_create(resultRelInfo->ri_RelationDesc,
&estate->es_tupleTable);
/* need an expression context to do the projection */
if (mtstate->ps.ps_ExprContext == NULL)
ExecAssignExprContext(estate, &mtstate->ps);
resultRelInfo->ri_projectNew =
ExecBuildUpdateProjection(subplan->targetlist,
false, /* subplan did the evaluation */
updateColnos,
relDesc,
mtstate->ps.ps_ExprContext,
resultRelInfo->ri_newTupleSlot,
&mtstate->ps);
resultRelInfo->ri_projectNewInfoValid = true;
}
/*
* ExecGetInsertNewTuple
* This prepares a "new" tuple ready to be inserted into given result
* relation, by removing any junk columns of the plan's output tuple
* and (if necessary) coercing the tuple to the right tuple format.
*/
static TupleTableSlot *
ExecGetInsertNewTuple(ResultRelInfo *relinfo,
TupleTableSlot *planSlot)
{
ProjectionInfo *newProj = relinfo->ri_projectNew;
ExprContext *econtext;
/*
* If there's no projection to be done, just make sure the slot is of the
* right type for the target rel. If the planSlot is the right type we
* can use it as-is, else copy the data into ri_newTupleSlot.
*/
if (newProj == NULL)
{
if (relinfo->ri_newTupleSlot->tts_ops != planSlot->tts_ops)
{
ExecCopySlot(relinfo->ri_newTupleSlot, planSlot);
return relinfo->ri_newTupleSlot;
}
else
return planSlot;
}
/*
* Else project; since the projection output slot is ri_newTupleSlot, this
* will also fix any slot-type problem.
*
* Note: currently, this is dead code, because INSERT cases don't receive
* any junk columns so there's never a projection to be done.
*/
econtext = newProj->pi_exprContext;
econtext->ecxt_outertuple = planSlot;
return ExecProject(newProj);
}
/*
* ExecGetUpdateNewTuple
* This prepares a "new" tuple by combining an UPDATE subplan's output
* tuple (which contains values of changed columns) with unchanged
* columns taken from the old tuple.
*
* The subplan tuple might also contain junk columns, which are ignored.
* Note that the projection also ensures we have a slot of the right type.
*/
TupleTableSlot *
ExecGetUpdateNewTuple(ResultRelInfo *relinfo,
TupleTableSlot *planSlot,
TupleTableSlot *oldSlot)
{
ProjectionInfo *newProj = relinfo->ri_projectNew;
ExprContext *econtext;
/* Use a few extra Asserts to protect against outside callers */
Assert(relinfo->ri_projectNewInfoValid);
Assert(planSlot != NULL && !TTS_EMPTY(planSlot));
Assert(oldSlot != NULL && !TTS_EMPTY(oldSlot));
econtext = newProj->pi_exprContext;
econtext->ecxt_outertuple = planSlot;
econtext->ecxt_scantuple = oldSlot;
return ExecProject(newProj);
}
/* ----------------------------------------------------------------
* ExecInsert
*
* For INSERT, we have to insert the tuple into the target relation
* (or partition thereof) and insert appropriate tuples into the index
* relations.
*
* slot contains the new tuple value to be stored.
*
* Returns RETURNING result if any, otherwise NULL.
* *inserted_tuple is the tuple that's effectively inserted;
* *insert_destrel is the relation where it was inserted.
* These are only set on success.
*
* This may change the currently active tuple conversion map in
* mtstate->mt_transition_capture, so the callers must take care to
* save the previous value to avoid losing track of it.
* ----------------------------------------------------------------
*/
static TupleTableSlot *
ExecInsert(ModifyTableContext *context,
ResultRelInfo *resultRelInfo,
TupleTableSlot *slot,
bool canSetTag,
TupleTableSlot **inserted_tuple,
ResultRelInfo **insert_destrel)
{
ModifyTableState *mtstate = context->mtstate;
EState *estate = context->estate;
Relation resultRelationDesc;
List *recheckIndexes = NIL;
TupleTableSlot *planSlot = context->planSlot;
TupleTableSlot *result = NULL;
TransitionCaptureState *ar_insert_trig_tcs;
ModifyTable *node = (ModifyTable *) mtstate->ps.plan;
OnConflictAction onconflict = node->onConflictAction;
PartitionTupleRouting *proute = mtstate->mt_partition_tuple_routing;
MemoryContext oldContext;
/*
* If the input result relation is a partitioned table, find the leaf
* partition to insert the tuple into.
*/
if (proute)
{
ResultRelInfo *partRelInfo;
slot = ExecPrepareTupleRouting(mtstate, estate, proute,
resultRelInfo, slot,
&partRelInfo);
resultRelInfo = partRelInfo;
}
ExecMaterializeSlot(slot);
resultRelationDesc = resultRelInfo->ri_RelationDesc;
/*
* Open the table's indexes, if we have not done so already, so that we
* can add new index entries for the inserted tuple.
*/
if (resultRelationDesc->rd_rel->relhasindex &&
resultRelInfo->ri_IndexRelationDescs == NULL)
ExecOpenIndices(resultRelInfo, onconflict != ONCONFLICT_NONE);
/*
* 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)
{
/* Flush any pending inserts, so rows are visible to the triggers */
if (estate->es_insert_pending_result_relations != NIL)
ExecPendingInserts(estate);
if (!ExecBRInsertTriggers(estate, resultRelInfo, slot))
return NULL; /* "do nothing" */
}
/* INSTEAD OF ROW INSERT Triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->trig_insert_instead_row)
{
if (!ExecIRInsertTriggers(estate, resultRelInfo, slot))
return NULL; /* "do nothing" */
}
else if (resultRelInfo->ri_FdwRoutine)
{
/*
* GENERATED expressions might reference the tableoid column, so
* (re-)initialize tts_tableOid before evaluating them.
*/
slot->tts_tableOid = RelationGetRelid(resultRelInfo->ri_RelationDesc);
/*
* Compute stored generated columns
*/
if (resultRelationDesc->rd_att->constr &&
resultRelationDesc->rd_att->constr->has_generated_stored)
ExecComputeStoredGenerated(resultRelInfo, estate, slot,
CMD_INSERT);
/*
* If the FDW supports batching, and batching is requested, accumulate
* rows and insert them in batches. Otherwise use the per-row inserts.
*/
if (resultRelInfo->ri_BatchSize > 1)
{
bool flushed = false;
/*
* When we've reached the desired batch size, perform the
* insertion.
*/
if (resultRelInfo->ri_NumSlots == resultRelInfo->ri_BatchSize)
{
ExecBatchInsert(mtstate, resultRelInfo,
resultRelInfo->ri_Slots,
resultRelInfo->ri_PlanSlots,
resultRelInfo->ri_NumSlots,
estate, canSetTag);
flushed = true;
}
oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
if (resultRelInfo->ri_Slots == NULL)
{
resultRelInfo->ri_Slots = palloc(sizeof(TupleTableSlot *) *
resultRelInfo->ri_BatchSize);
resultRelInfo->ri_PlanSlots = palloc(sizeof(TupleTableSlot *) *
resultRelInfo->ri_BatchSize);
}
/*
* Initialize the batch slots. We don't know how many slots will
* be needed, so we initialize them as the batch grows, and we
* keep them across batches. To mitigate an inefficiency in how
* resource owner handles objects with many references (as with
* many slots all referencing the same tuple descriptor) we copy
* the appropriate tuple descriptor for each slot.
*/
if (resultRelInfo->ri_NumSlots >= resultRelInfo->ri_NumSlotsInitialized)
{
TupleDesc tdesc = CreateTupleDescCopy(slot->tts_tupleDescriptor);
TupleDesc plan_tdesc =
CreateTupleDescCopy(planSlot->tts_tupleDescriptor);
resultRelInfo->ri_Slots[resultRelInfo->ri_NumSlots] =
MakeSingleTupleTableSlot(tdesc, slot->tts_ops);
resultRelInfo->ri_PlanSlots[resultRelInfo->ri_NumSlots] =
MakeSingleTupleTableSlot(plan_tdesc, planSlot->tts_ops);
/* remember how many batch slots we initialized */
resultRelInfo->ri_NumSlotsInitialized++;
}
ExecCopySlot(resultRelInfo->ri_Slots[resultRelInfo->ri_NumSlots],
slot);
ExecCopySlot(resultRelInfo->ri_PlanSlots[resultRelInfo->ri_NumSlots],
planSlot);
/*
* If these are the first tuples stored in the buffers, add the
* target rel and the mtstate to the
* es_insert_pending_result_relations and
* es_insert_pending_modifytables lists respectively, except in
* the case where flushing was done above, in which case they
* would already have been added to the lists, so no need to do
* this.
*/
if (resultRelInfo->ri_NumSlots == 0 && !flushed)
{
Assert(!list_member_ptr(estate->es_insert_pending_result_relations,
resultRelInfo));
estate->es_insert_pending_result_relations =
lappend(estate->es_insert_pending_result_relations,
resultRelInfo);
estate->es_insert_pending_modifytables =
lappend(estate->es_insert_pending_modifytables, mtstate);
}
Assert(list_member_ptr(estate->es_insert_pending_result_relations,
resultRelInfo));
resultRelInfo->ri_NumSlots++;
MemoryContextSwitchTo(oldContext);
return NULL;
}
/*
* 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;
/*
* AFTER ROW Triggers or RETURNING expressions might reference the
* tableoid column, so (re-)initialize tts_tableOid before evaluating
* them. (This covers the case where the FDW replaced the slot.)
*/
slot->tts_tableOid = RelationGetRelid(resultRelInfo->ri_RelationDesc);
}
else
{
WCOKind wco_kind;
/*
* Constraints and GENERATED expressions might reference the tableoid
* column, so (re-)initialize tts_tableOid before evaluating them.
*/
slot->tts_tableOid = RelationGetRelid(resultRelationDesc);
/*
* Compute stored generated columns
*/
if (resultRelationDesc->rd_att->constr &&
resultRelationDesc->rd_att->constr->has_generated_stored)
ExecComputeStoredGenerated(resultRelInfo, estate, slot,
CMD_INSERT);
/*
* Check any RLS WITH CHECK policies.
*
* Normally we should check INSERT policies. But if the insert is the
* result of a partition key update that moved the tuple to a new
* partition, we should instead check UPDATE policies, because we are
* executing policies defined on the target table, and not those
* defined on the child partitions.
*
* If we're running MERGE, we refer to the action that we're executing
* to know if we're doing an INSERT or UPDATE to a partition table.
*/
if (mtstate->operation == CMD_UPDATE)
wco_kind = WCO_RLS_UPDATE_CHECK;
else if (mtstate->operation == CMD_MERGE)
wco_kind = (mtstate->mt_merge_action->mas_action->commandType == CMD_UPDATE) ?
WCO_RLS_UPDATE_CHECK : WCO_RLS_INSERT_CHECK;
else
wco_kind = WCO_RLS_INSERT_CHECK;
/*
* 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_kind, resultRelInfo, slot, estate);
/*
* Check the constraints of the tuple.
*/
if (resultRelationDesc->rd_att->constr)
ExecConstraints(resultRelInfo, slot, estate);
/*
* Also check the tuple against the partition constraint, if there is
* one; except that if we got here via tuple-routing, we don't need to
* if there's no BR trigger defined on the partition.
*/
if (resultRelationDesc->rd_rel->relispartition &&
(resultRelInfo->ri_RootResultRelInfo == NULL ||
(resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->trig_insert_before_row)))
ExecPartitionCheck(resultRelInfo, slot, estate, true);
if (onconflict != ONCONFLICT_NONE && resultRelInfo->ri_NumIndices > 0)
{
/* Perform a speculative insertion. */
uint32 specToken;
ItemPointerData conflictTid;
bool specConflict;
List *arbiterIndexes;
arbiterIndexes = resultRelInfo->ri_onConflictArbiterIndexes;
/*
* 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. Better allow interrupts in case some bug makes
* this an infinite loop.
*/
vlock:
CHECK_FOR_INTERRUPTS();
specConflict = false;
if (!ExecCheckIndexConstraints(resultRelInfo, 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(context, resultRelInfo,
&conflictTid, slot, canSetTag,
&returning))
{
InstrCountTuples2(&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.
*
* Using ExecGetReturningSlot() to store the tuple for the
* recheck isn't that pretty, but we can't trivially use
* the input slot, because it might not be of a compatible
* type. As there's no conflicting usage of
* ExecGetReturningSlot() in the DO NOTHING case...
*/
Assert(onconflict == ONCONFLICT_NOTHING);
ExecCheckTIDVisible(estate, resultRelInfo, &conflictTid,
ExecGetReturningSlot(estate, resultRelInfo));
InstrCountTuples2(&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());
/* insert the tuple, with the speculative token */
table_tuple_insert_speculative(resultRelationDesc, slot,
estate->es_output_cid,
0,
NULL,
specToken);
/* insert index entries for tuple */
recheckIndexes = ExecInsertIndexTuples(resultRelInfo,
slot, estate, false, true,
&specConflict,
arbiterIndexes,
false);
/* adjust the tuple's state accordingly */
table_tuple_complete_speculative(resultRelationDesc, slot,
specToken, !specConflict);
/*
* 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 */
table_tuple_insert(resultRelationDesc, slot,
estate->es_output_cid,
0, NULL);
/* insert index entries for tuple */
if (resultRelInfo->ri_NumIndices > 0)
recheckIndexes = ExecInsertIndexTuples(resultRelInfo,
slot, estate, false,
false, NULL, NIL,
false);
}
}
if (canSetTag)
(estate->es_processed)++;
/*
* If this insert is the result of a partition key update that moved the
* tuple to a new partition, put this row into the transition NEW TABLE,
* if there is one. We need to do this separately for DELETE and INSERT
* because they happen on different tables.
*/
ar_insert_trig_tcs = mtstate->mt_transition_capture;
if (mtstate->operation == CMD_UPDATE && mtstate->mt_transition_capture
&& mtstate->mt_transition_capture->tcs_update_new_table)
{
ExecARUpdateTriggers(estate, resultRelInfo,
NULL, NULL,
NULL,
NULL,
slot,
NULL,
mtstate->mt_transition_capture,
false);
/*
* We've already captured the NEW TABLE row, so make sure any AR
* INSERT trigger fired below doesn't capture it again.
*/
ar_insert_trig_tcs = NULL;
}
/* AFTER ROW INSERT Triggers */
ExecARInsertTriggers(estate, resultRelInfo, slot, recheckIndexes,
ar_insert_trig_tcs);
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)
result = ExecProcessReturning(resultRelInfo, slot, planSlot);
if (inserted_tuple)
*inserted_tuple = slot;
if (insert_destrel)
*insert_destrel = resultRelInfo;
return result;
}
/* ----------------------------------------------------------------
* ExecBatchInsert
*
* Insert multiple tuples in an efficient way.
* Currently, this handles inserting into a foreign table without
* RETURNING clause.
* ----------------------------------------------------------------
*/
static void
ExecBatchInsert(ModifyTableState *mtstate,
ResultRelInfo *resultRelInfo,
TupleTableSlot **slots,
TupleTableSlot **planSlots,
int numSlots,
EState *estate,
bool canSetTag)
{
int i;
int numInserted = numSlots;
TupleTableSlot *slot = NULL;
TupleTableSlot **rslots;
/*
* insert into foreign table: let the FDW do it
*/
rslots = resultRelInfo->ri_FdwRoutine->ExecForeignBatchInsert(estate,
resultRelInfo,
slots,
planSlots,
&numInserted);
for (i = 0; i < numInserted; i++)
{
slot = rslots[i];
/*
* AFTER ROW Triggers might reference the tableoid column, so
* (re-)initialize tts_tableOid before evaluating them.
*/
slot->tts_tableOid = RelationGetRelid(resultRelInfo->ri_RelationDesc);
/* AFTER ROW INSERT Triggers */
ExecARInsertTriggers(estate, resultRelInfo, slot, NIL,
mtstate->mt_transition_capture);
/*
* Check any WITH CHECK OPTION constraints from parent views. See the
* comment in ExecInsert.
*/
if (resultRelInfo->ri_WithCheckOptions != NIL)
ExecWithCheckOptions(WCO_VIEW_CHECK, resultRelInfo, slot, estate);
}
if (canSetTag && numInserted > 0)
estate->es_processed += numInserted;
/* Clean up all the slots, ready for the next batch */
for (i = 0; i < numSlots; i++)
{
ExecClearTuple(slots[i]);
ExecClearTuple(planSlots[i]);
}
resultRelInfo->ri_NumSlots = 0;
}
/*
* ExecPendingInserts -- flushes all pending inserts to the foreign tables
*/
static void
ExecPendingInserts(EState *estate)
{
ListCell *l1,
*l2;
forboth(l1, estate->es_insert_pending_result_relations,
l2, estate->es_insert_pending_modifytables)
{
ResultRelInfo *resultRelInfo = (ResultRelInfo *) lfirst(l1);
ModifyTableState *mtstate = (ModifyTableState *) lfirst(l2);
Assert(mtstate);
ExecBatchInsert(mtstate, resultRelInfo,
resultRelInfo->ri_Slots,
resultRelInfo->ri_PlanSlots,
resultRelInfo->ri_NumSlots,
estate, mtstate->canSetTag);
}
list_free(estate->es_insert_pending_result_relations);
list_free(estate->es_insert_pending_modifytables);
estate->es_insert_pending_result_relations = NIL;
estate->es_insert_pending_modifytables = NIL;
}
/*
* ExecDeletePrologue -- subroutine for ExecDelete
*
* Prepare executor state for DELETE. Actually, the only thing we have to do
* here is execute BEFORE ROW triggers. We return false if one of them makes
* the delete a no-op; otherwise, return true.
*/
static bool
ExecDeletePrologue(ModifyTableContext *context, ResultRelInfo *resultRelInfo,
ItemPointer tupleid, HeapTuple oldtuple,
TupleTableSlot **epqreturnslot, TM_Result *result)
{
if (result)
*result = TM_Ok;
/* BEFORE ROW DELETE triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->trig_delete_before_row)
{
/* Flush any pending inserts, so rows are visible to the triggers */
if (context->estate->es_insert_pending_result_relations != NIL)
ExecPendingInserts(context->estate);
return ExecBRDeleteTriggers(context->estate, context->epqstate,
resultRelInfo, tupleid, oldtuple,
epqreturnslot, result, &context->tmfd);
}
return true;
}
/*
* ExecDeleteAct -- subroutine for ExecDelete
*
* Actually delete the tuple from a plain table.
*
* Caller is in charge of doing EvalPlanQual as necessary
*/
static TM_Result
ExecDeleteAct(ModifyTableContext *context, ResultRelInfo *resultRelInfo,
ItemPointer tupleid, bool changingPart)
{
EState *estate = context->estate;
return table_tuple_delete(resultRelInfo->ri_RelationDesc, tupleid,
estate->es_output_cid,
estate->es_snapshot,
estate->es_crosscheck_snapshot,
true /* wait for commit */ ,
&context->tmfd,
changingPart);
}
/*
* ExecDeleteEpilogue -- subroutine for ExecDelete
*
* Closing steps of tuple deletion; this invokes AFTER FOR EACH ROW triggers,
* including the UPDATE triggers if the deletion is being done as part of a
* cross-partition tuple move.
*/
static void
ExecDeleteEpilogue(ModifyTableContext *context, ResultRelInfo *resultRelInfo,
ItemPointer tupleid, HeapTuple oldtuple, bool changingPart)
{
ModifyTableState *mtstate = context->mtstate;
EState *estate = context->estate;
TransitionCaptureState *ar_delete_trig_tcs;
/*
* If this delete is the result of a partition key update that moved the
* tuple to a new partition, put this row into the transition OLD TABLE,
* if there is one. We need to do this separately for DELETE and INSERT
* because they happen on different tables.
*/
ar_delete_trig_tcs = mtstate->mt_transition_capture;
if (mtstate->operation == CMD_UPDATE && mtstate->mt_transition_capture &&
mtstate->mt_transition_capture->tcs_update_old_table)
{
ExecARUpdateTriggers(estate, resultRelInfo,
NULL, NULL,
tupleid, oldtuple,
NULL, NULL, mtstate->mt_transition_capture,
false);
/*
* We've already captured the OLD TABLE row, so make sure any AR
* DELETE trigger fired below doesn't capture it again.
*/
ar_delete_trig_tcs = NULL;
}
/* AFTER ROW DELETE Triggers */
ExecARDeleteTriggers(estate, resultRelInfo, tupleid, oldtuple,
ar_delete_trig_tcs, changingPart);
}
/* ----------------------------------------------------------------
* 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 through a view INSTEAD OF trigger,
* oldtuple is passed to the 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. We use
* tupleDeleted to indicate whether the tuple is actually deleted,
* callers can use it to decide whether to continue the operation. When
* this DELETE is a part of an UPDATE of partition-key, then the slot
* returned by EvalPlanQual() is passed back using output parameter
* epqreturnslot.
*
* Returns RETURNING result if any, otherwise NULL.
* ----------------------------------------------------------------
*/
static TupleTableSlot *
ExecDelete(ModifyTableContext *context,
ResultRelInfo *resultRelInfo,
ItemPointer tupleid,
HeapTuple oldtuple,
bool processReturning,
bool changingPart,
bool canSetTag,
TM_Result *tmresult,
bool *tupleDeleted,
TupleTableSlot **epqreturnslot)
{
EState *estate = context->estate;
Relation resultRelationDesc = resultRelInfo->ri_RelationDesc;
TupleTableSlot *slot = NULL;
TM_Result result;
if (tupleDeleted)
*tupleDeleted = false;
/*
* Prepare for the delete. This includes BEFORE ROW triggers, so we're
* done if it says we are.
*/
if (!ExecDeletePrologue(context, resultRelInfo, tupleid, oldtuple,
epqreturnslot, tmresult))
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 returning slot as a place to store RETURNING data,
* although the FDW can return some other slot if it wants.
*/
slot = ExecGetReturningSlot(estate, resultRelInfo);
slot = resultRelInfo->ri_FdwRoutine->ExecForeignDelete(estate,
resultRelInfo,
slot,
context->planSlot);
if (slot == NULL) /* "do nothing" */
return NULL;
/*
* RETURNING expressions might reference the tableoid column, so
* (re)initialize tts_tableOid before evaluating them.
*/
if (TTS_EMPTY(slot))
ExecStoreAllNullTuple(slot);
slot->tts_tableOid = RelationGetRelid(resultRelationDesc);
}
else
{
/*
* delete the tuple
*
* Note: if context->estate->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 = ExecDeleteAct(context, resultRelInfo, tupleid, changingPart);
if (tmresult)
*tmresult = result;
switch (result)
{
case TM_SelfModified:
/*
* 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 (context->tmfd.cmax != estate->es_output_cid)
ereport(ERROR,
(errcode(ERRCODE_TRIGGERED_DATA_CHANGE_VIOLATION),
errmsg("tuple to be deleted 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 TM_Ok:
break;
case TM_Updated:
{
TupleTableSlot *inputslot;
TupleTableSlot *epqslot;
if (IsolationUsesXactSnapshot())
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent update")));
/*
* Already know that we're going to need to do EPQ, so
* fetch tuple directly into the right slot.
*/
EvalPlanQualBegin(context->epqstate);
inputslot = EvalPlanQualSlot(context->epqstate, resultRelationDesc,
resultRelInfo->ri_RangeTableIndex);
result = table_tuple_lock(resultRelationDesc, tupleid,
estate->es_snapshot,
inputslot, estate->es_output_cid,
LockTupleExclusive, LockWaitBlock,
TUPLE_LOCK_FLAG_FIND_LAST_VERSION,
&context->tmfd);
switch (result)
{
case TM_Ok:
Assert(context->tmfd.traversed);
epqslot = EvalPlanQual(context->epqstate,
resultRelationDesc,
resultRelInfo->ri_RangeTableIndex,
inputslot);
if (TupIsNull(epqslot))
/* Tuple not passing quals anymore, exiting... */
return NULL;
/*
* If requested, skip delete and pass back the
* updated row.
*/
if (epqreturnslot)
{
*epqreturnslot = epqslot;
return NULL;
}
else
goto ldelete;
case TM_SelfModified:
/*
* This can be reached when following an update
* chain from a tuple updated by another session,
* reaching a tuple that was already updated in
* this transaction. If previously updated by this
* command, ignore the delete, otherwise error
* out.
*
* See also TM_SelfModified response to
* table_tuple_delete() above.
*/
if (context->tmfd.cmax != estate->es_output_cid)
ereport(ERROR,
(errcode(ERRCODE_TRIGGERED_DATA_CHANGE_VIOLATION),
errmsg("tuple to be deleted 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.")));
return NULL;
case TM_Deleted:
/* tuple already deleted; nothing to do */
return NULL;
default:
/*
* TM_Invisible should be impossible because we're
* waiting for updated row versions, and would
* already have errored out if the first version
* is invisible.
*
* TM_Updated should be impossible, because we're
* locking the latest version via
* TUPLE_LOCK_FLAG_FIND_LAST_VERSION.
*/
elog(ERROR, "unexpected table_tuple_lock status: %u",
result);
return NULL;
}
Assert(false);
break;
}
case TM_Deleted:
if (IsolationUsesXactSnapshot())
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent delete")));
/* tuple already deleted; nothing to do */
return NULL;
default:
elog(ERROR, "unrecognized table_tuple_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)++;
/* Tell caller that the delete actually happened. */
if (tupleDeleted)
*tupleDeleted = true;
ExecDeleteEpilogue(context, resultRelInfo, tupleid, oldtuple, changingPart);
/* Process RETURNING if present and if requested */
if (processReturning && 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;
if (resultRelInfo->ri_FdwRoutine)
{
/* FDW must have provided a slot containing the deleted row */
Assert(!TupIsNull(slot));
}
else
{
slot = ExecGetReturningSlot(estate, resultRelInfo);
if (oldtuple != NULL)
{
ExecForceStoreHeapTuple(oldtuple, slot, false);
}
else
{
if (!table_tuple_fetch_row_version(resultRelationDesc, tupleid,
SnapshotAny, slot))
elog(ERROR, "failed to fetch deleted tuple for DELETE RETURNING");
}
}
rslot = ExecProcessReturning(resultRelInfo, slot, context->planSlot);
/*
* Before releasing the target tuple again, make sure rslot has a
* local copy of any pass-by-reference values.
*/
ExecMaterializeSlot(rslot);
ExecClearTuple(slot);
return rslot;
}
return NULL;
}
/*
* ExecCrossPartitionUpdate --- Move an updated tuple to another partition.
*
* This works by first deleting the old tuple from the current partition,
* followed by inserting the new tuple into the root parent table, that is,
* mtstate->rootResultRelInfo. It will be re-routed from there to the
* correct partition.
*
* Returns true if the tuple has been successfully moved, or if it's found
* that the tuple was concurrently deleted so there's nothing more to do
* for the caller.
*
* False is returned if the tuple we're trying to move is found to have been
* concurrently updated. In that case, the caller must check if the updated
* tuple that's returned in *retry_slot still needs to be re-routed, and call
* this function again or perform a regular update accordingly. For MERGE,
* the updated tuple is not returned in *retry_slot; it has its own retry
* logic.
*/
static bool
ExecCrossPartitionUpdate(ModifyTableContext *context,
ResultRelInfo *resultRelInfo,
ItemPointer tupleid, HeapTuple oldtuple,
TupleTableSlot *slot,
bool canSetTag,
UpdateContext *updateCxt,
TM_Result *tmresult,
TupleTableSlot **retry_slot,
TupleTableSlot **inserted_tuple,
ResultRelInfo **insert_destrel)
{
ModifyTableState *mtstate = context->mtstate;
EState *estate = mtstate->ps.state;
TupleConversionMap *tupconv_map;
bool tuple_deleted;
TupleTableSlot *epqslot = NULL;
context->cpUpdateReturningSlot = NULL;
*retry_slot = NULL;
/*
* Disallow an INSERT ON CONFLICT DO UPDATE that causes the original row
* to migrate to a different partition. Maybe this can be implemented
* some day, but it seems a fringe feature with little redeeming value.
*/
if (((ModifyTable *) mtstate->ps.plan)->onConflictAction == ONCONFLICT_UPDATE)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("invalid ON UPDATE specification"),
errdetail("The result tuple would appear in a different partition than the original tuple.")));
/*
* When an UPDATE is run directly on a leaf partition, simply fail with a
* partition constraint violation error.
*/
if (resultRelInfo == mtstate->rootResultRelInfo)
ExecPartitionCheckEmitError(resultRelInfo, slot, estate);
/* Initialize tuple routing info if not already done. */
if (mtstate->mt_partition_tuple_routing == NULL)
{
Relation rootRel = mtstate->rootResultRelInfo->ri_RelationDesc;
MemoryContext oldcxt;
/* Things built here have to last for the query duration. */
oldcxt = MemoryContextSwitchTo(estate->es_query_cxt);
mtstate->mt_partition_tuple_routing =
ExecSetupPartitionTupleRouting(estate, rootRel);
/*
* Before a partition's tuple can be re-routed, it must first be
* converted to the root's format, so we'll need a slot for storing
* such tuples.
*/
Assert(mtstate->mt_root_tuple_slot == NULL);
mtstate->mt_root_tuple_slot = table_slot_create(rootRel, NULL);
MemoryContextSwitchTo(oldcxt);
}
/*
* Row movement, part 1. Delete the tuple, but skip RETURNING processing.
* We want to return rows from INSERT.
*/
ExecDelete(context, resultRelInfo,
tupleid, oldtuple,
false, /* processReturning */
true, /* changingPart */
false, /* canSetTag */
tmresult, &tuple_deleted, &epqslot);
/*
* For some reason if DELETE didn't happen (e.g. trigger prevented it, or
* it was already deleted by self, or it was concurrently deleted by
* another transaction), then we should skip the insert as well;
* otherwise, an UPDATE could cause an increase in the total number of
* rows across all partitions, which is clearly wrong.
*
* For a normal UPDATE, the case where the tuple has been the subject of a
* concurrent UPDATE or DELETE would be handled by the EvalPlanQual
* machinery, but for an UPDATE that we've translated into a DELETE from
* this partition and an INSERT into some other partition, that's not
* available, because CTID chains can't span relation boundaries. We
* mimic the semantics to a limited extent by skipping the INSERT if the
* DELETE fails to find a tuple. This ensures that two concurrent
* attempts to UPDATE the same tuple at the same time can't turn one tuple
* into two, and that an UPDATE of a just-deleted tuple can't resurrect
* it.
*/
if (!tuple_deleted)
{
/*
* epqslot will be typically NULL. But when ExecDelete() finds that
* another transaction has concurrently updated the same row, it
* re-fetches the row, skips the delete, and epqslot is set to the
* re-fetched tuple slot. In that case, we need to do all the checks
* again. For MERGE, we leave everything to the caller (it must do
* additional rechecking, and might end up executing a different
* action entirely).
*/
if (mtstate->operation == CMD_MERGE)
return *tmresult == TM_Ok;
else if (TupIsNull(epqslot))
return true;
else
{
/* Fetch the most recent version of old tuple. */
TupleTableSlot *oldSlot;
/* ... but first, make sure ri_oldTupleSlot is initialized. */
if (unlikely(!resultRelInfo->ri_projectNewInfoValid))
ExecInitUpdateProjection(mtstate, resultRelInfo);
oldSlot = resultRelInfo->ri_oldTupleSlot;
if (!table_tuple_fetch_row_version(resultRelInfo->ri_RelationDesc,
tupleid,
SnapshotAny,
oldSlot))
elog(ERROR, "failed to fetch tuple being updated");
/* and project the new tuple to retry the UPDATE with */
*retry_slot = ExecGetUpdateNewTuple(resultRelInfo, epqslot,
oldSlot);
return false;
}
}
/*
* resultRelInfo is one of the per-relation resultRelInfos. So we should
* convert the tuple into root's tuple descriptor if needed, since
* ExecInsert() starts the search from root.
*/
tupconv_map = ExecGetChildToRootMap(resultRelInfo);
if (tupconv_map != NULL)
slot = execute_attr_map_slot(tupconv_map->attrMap,
slot,
mtstate->mt_root_tuple_slot);
/* Tuple routing starts from the root table. */
context->cpUpdateReturningSlot =
ExecInsert(context, mtstate->rootResultRelInfo, slot, canSetTag,
inserted_tuple, insert_destrel);
/*
* Reset the transition state that may possibly have been written by
* INSERT.
*/
if (mtstate->mt_transition_capture)
mtstate->mt_transition_capture->tcs_original_insert_tuple = NULL;
/* We're done moving. */
return true;
}
/*
* ExecUpdatePrologue -- subroutine for ExecUpdate
*
* Prepare executor state for UPDATE. This includes running BEFORE ROW
* triggers. We return false if one of them makes the update a no-op;
* otherwise, return true.
*/
static bool
ExecUpdatePrologue(ModifyTableContext *context, ResultRelInfo *resultRelInfo,
ItemPointer tupleid, HeapTuple oldtuple, TupleTableSlot *slot,
TM_Result *result)
{
Relation resultRelationDesc = resultRelInfo->ri_RelationDesc;
if (result)
*result = TM_Ok;
ExecMaterializeSlot(slot);
/*
* Open the table's indexes, if we have not done so already, so that we
* can add new index entries for the updated tuple.
*/
if (resultRelationDesc->rd_rel->relhasindex &&
resultRelInfo->ri_IndexRelationDescs == NULL)
ExecOpenIndices(resultRelInfo, false);
/* BEFORE ROW UPDATE triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->trig_update_before_row)
{
/* Flush any pending inserts, so rows are visible to the triggers */
if (context->estate->es_insert_pending_result_relations != NIL)
ExecPendingInserts(context->estate);
return ExecBRUpdateTriggers(context->estate, context->epqstate,
resultRelInfo, tupleid, oldtuple, slot,
result, &context->tmfd);
}
return true;
}
/*
* ExecUpdatePrepareSlot -- subroutine for ExecUpdateAct
*
* Apply the final modifications to the tuple slot before the update.
* (This is split out because we also need it in the foreign-table code path.)
*/
static void
ExecUpdatePrepareSlot(ResultRelInfo *resultRelInfo,
TupleTableSlot *slot,
EState *estate)
{
Relation resultRelationDesc = resultRelInfo->ri_RelationDesc;
/*
* Constraints and GENERATED expressions might reference the tableoid
* column, so (re-)initialize tts_tableOid before evaluating them.
*/
slot->tts_tableOid = RelationGetRelid(resultRelationDesc);
/*
* Compute stored generated columns
*/
if (resultRelationDesc->rd_att->constr &&
resultRelationDesc->rd_att->constr->has_generated_stored)
ExecComputeStoredGenerated(resultRelInfo, estate, slot,
CMD_UPDATE);
}
/*
* ExecUpdateAct -- subroutine for ExecUpdate
*
* Actually update the tuple, when operating on a plain table. If the
* table is a partition, and the command was called referencing an ancestor
* partitioned table, this routine migrates the resulting tuple to another
* partition.
*
* The caller is in charge of keeping indexes current as necessary. The
* caller is also in charge of doing EvalPlanQual if the tuple is found to
* be concurrently updated. However, in case of a cross-partition update,
* this routine does it.
*/
static TM_Result
ExecUpdateAct(ModifyTableContext *context, ResultRelInfo *resultRelInfo,
ItemPointer tupleid, HeapTuple oldtuple, TupleTableSlot *slot,
bool canSetTag, UpdateContext *updateCxt)
{
EState *estate = context->estate;
Relation resultRelationDesc = resultRelInfo->ri_RelationDesc;
bool partition_constraint_failed;
TM_Result result;
updateCxt->crossPartUpdate = false;
/*
* If we move the tuple to a new partition, we loop back here to recompute
* GENERATED values (which are allowed to be different across partitions)
* and recheck any RLS policies and constraints. We do not fire any
* BEFORE triggers of the new partition, however.
*/
lreplace:
/* Fill in GENERATEd columns */
ExecUpdatePrepareSlot(resultRelInfo, slot, estate);
/* ensure slot is independent, consider e.g. EPQ */
ExecMaterializeSlot(slot);
/*
* If partition constraint fails, this row might get moved to another
* partition, in which case we should check the RLS CHECK policy just
* before inserting into the new partition, rather than doing it here.
* This is because a trigger on that partition might again change the row.
* So skip the WCO checks if the partition constraint fails.
*/
partition_constraint_failed =
resultRelationDesc->rd_rel->relispartition &&
!ExecPartitionCheck(resultRelInfo, slot, estate, false);
/* Check any RLS UPDATE WITH CHECK policies */
if (!partition_constraint_failed &&
resultRelInfo->ri_WithCheckOptions != NIL)
{
/*
* ExecWithCheckOptions() will skip any WCOs which are not of the kind
* we are looking for at this point.
*/
ExecWithCheckOptions(WCO_RLS_UPDATE_CHECK,
resultRelInfo, slot, estate);
}
/*
* If a partition check failed, try to move the row into the right
* partition.
*/
if (partition_constraint_failed)
{
TupleTableSlot *inserted_tuple,
*retry_slot;
ResultRelInfo *insert_destrel = NULL;
/*
* ExecCrossPartitionUpdate will first DELETE the row from the
* partition it's currently in and then insert it back into the root
* table, which will re-route it to the correct partition. However,
* if the tuple has been concurrently updated, a retry is needed.
*/
if (ExecCrossPartitionUpdate(context, resultRelInfo,
tupleid, oldtuple, slot,
canSetTag, updateCxt,
&result,
&retry_slot,
&inserted_tuple,
&insert_destrel))
{
/* success! */
updateCxt->crossPartUpdate = true;
/*
* If the partitioned table being updated is referenced in foreign
* keys, queue up trigger events to check that none of them were
* violated. No special treatment is needed in
* non-cross-partition update situations, because the leaf
* partition's AR update triggers will take care of that. During
* cross-partition updates implemented as delete on the source
* partition followed by insert on the destination partition,
* AR-UPDATE triggers of the root table (that is, the table
* mentioned in the query) must be fired.
*
* NULL insert_destrel means that the move failed to occur, that
* is, the update failed, so no need to anything in that case.
*/
if (insert_destrel &&
resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->trig_update_after_row)
ExecCrossPartitionUpdateForeignKey(context,
resultRelInfo,
insert_destrel,
tupleid, slot,
inserted_tuple);
return TM_Ok;
}
/*
* No luck, a retry is needed. If running MERGE, we do not do so
* here; instead let it handle that on its own rules.
*/
if (context->mtstate->operation == CMD_MERGE)
return result;
/*
* ExecCrossPartitionUpdate installed an updated version of the new
* tuple in the retry slot; start over.
*/
slot = retry_slot;
goto lreplace;
}
/*
* Check the constraints of the tuple. We've already checked the
* partition constraint above; however, we must still ensure the tuple
* passes all other constraints, so we will call ExecConstraints() and
* have it validate all remaining checks.
*/
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 = table_tuple_update(resultRelationDesc, tupleid, slot,
estate->es_output_cid,
estate->es_snapshot,
estate->es_crosscheck_snapshot,
true /* wait for commit */ ,
&context->tmfd, &updateCxt->lockmode,
&updateCxt->updateIndexes);
return result;
}
/*
* ExecUpdateEpilogue -- subroutine for ExecUpdate
*
* Closing steps of updating a tuple. Must be called if ExecUpdateAct
* returns indicating that the tuple was updated.
*/
static void
ExecUpdateEpilogue(ModifyTableContext *context, UpdateContext *updateCxt,
ResultRelInfo *resultRelInfo, ItemPointer tupleid,
HeapTuple oldtuple, TupleTableSlot *slot)
{
ModifyTableState *mtstate = context->mtstate;
List *recheckIndexes = NIL;
/* insert index entries for tuple if necessary */
if (resultRelInfo->ri_NumIndices > 0 && (updateCxt->updateIndexes != TU_None))
recheckIndexes = ExecInsertIndexTuples(resultRelInfo,
slot, context->estate,
true, false,
NULL, NIL,
(updateCxt->updateIndexes == TU_Summarizing));
/* AFTER ROW UPDATE Triggers */
ExecARUpdateTriggers(context->estate, resultRelInfo,
NULL, NULL,
tupleid, oldtuple, slot,
recheckIndexes,
mtstate->operation == CMD_INSERT ?
mtstate->mt_oc_transition_capture :
mtstate->mt_transition_capture,
false);
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, context->estate);
}
/*
* Queues up an update event using the target root partitioned table's
* trigger to check that a cross-partition update hasn't broken any foreign
* keys pointing into it.
*/
static void
ExecCrossPartitionUpdateForeignKey(ModifyTableContext *context,
ResultRelInfo *sourcePartInfo,
ResultRelInfo *destPartInfo,
ItemPointer tupleid,
TupleTableSlot *oldslot,
TupleTableSlot *newslot)
{
ListCell *lc;
ResultRelInfo *rootRelInfo;
List *ancestorRels;
rootRelInfo = sourcePartInfo->ri_RootResultRelInfo;
ancestorRels = ExecGetAncestorResultRels(context->estate, sourcePartInfo);
/*
* For any foreign keys that point directly into a non-root ancestors of
* the source partition, we can in theory fire an update event to enforce
* those constraints using their triggers, if we could tell that both the
* source and the destination partitions are under the same ancestor. But
* for now, we simply report an error that those cannot be enforced.
*/
foreach(lc, ancestorRels)
{
ResultRelInfo *rInfo = lfirst(lc);
TriggerDesc *trigdesc = rInfo->ri_TrigDesc;
bool has_noncloned_fkey = false;
/* Root ancestor's triggers will be processed. */
if (rInfo == rootRelInfo)
continue;
if (trigdesc && trigdesc->trig_update_after_row)
{
for (int i = 0; i < trigdesc->numtriggers; i++)
{
Trigger *trig = &trigdesc->triggers[i];
if (!trig->tgisclone &&
RI_FKey_trigger_type(trig->tgfoid) == RI_TRIGGER_PK)
{
has_noncloned_fkey = true;
break;
}
}
}
if (has_noncloned_fkey)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot move tuple across partitions when a non-root ancestor of the source partition is directly referenced in a foreign key"),
errdetail("A foreign key points to ancestor \"%s\" but not the root ancestor \"%s\".",
RelationGetRelationName(rInfo->ri_RelationDesc),
RelationGetRelationName(rootRelInfo->ri_RelationDesc)),
errhint("Consider defining the foreign key on table \"%s\".",
RelationGetRelationName(rootRelInfo->ri_RelationDesc))));
}
/* Perform the root table's triggers. */
ExecARUpdateTriggers(context->estate,
rootRelInfo, sourcePartInfo, destPartInfo,
tupleid, NULL, newslot, NIL, NULL, true);
}
/* ----------------------------------------------------------------
* 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 through a view INSTEAD OF trigger,
* oldtuple is passed to the 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.
*
* slot contains the new tuple value to be stored.
* planSlot is the output of the ModifyTable's subplan; we use it
* to access values from other input tables (for RETURNING),
* row-ID junk columns, etc.
*
* Returns RETURNING result if any, otherwise NULL. On exit, if tupleid
* had identified the tuple to update, it will identify the tuple
* actually updated after EvalPlanQual.
* ----------------------------------------------------------------
*/
static TupleTableSlot *
ExecUpdate(ModifyTableContext *context, ResultRelInfo *resultRelInfo,
ItemPointer tupleid, HeapTuple oldtuple, TupleTableSlot *slot,
bool canSetTag)
{
EState *estate = context->estate;
Relation resultRelationDesc = resultRelInfo->ri_RelationDesc;
UpdateContext updateCxt = {0};
TM_Result result;
/*
* abort the operation if not running transactions
*/
if (IsBootstrapProcessingMode())
elog(ERROR, "cannot UPDATE during bootstrap");
/*
* Prepare for the update. This includes BEFORE ROW triggers, so we're
* done if it says we are.
*/
if (!ExecUpdatePrologue(context, resultRelInfo, tupleid, oldtuple, slot, NULL))
return NULL;
/* INSTEAD OF ROW UPDATE Triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->trig_update_instead_row)
{
if (!ExecIRUpdateTriggers(estate, resultRelInfo,
oldtuple, slot))
return NULL; /* "do nothing" */
}
else if (resultRelInfo->ri_FdwRoutine)
{
/* Fill in GENERATEd columns */
ExecUpdatePrepareSlot(resultRelInfo, slot, estate);
/*
* update in foreign table: let the FDW do it
*/
slot = resultRelInfo->ri_FdwRoutine->ExecForeignUpdate(estate,
resultRelInfo,
slot,
context->planSlot);
if (slot == NULL) /* "do nothing" */
return NULL;
/*
* AFTER ROW Triggers or RETURNING expressions might reference the
* tableoid column, so (re-)initialize tts_tableOid before evaluating
* them. (This covers the case where the FDW replaced the slot.)
*/
slot->tts_tableOid = RelationGetRelid(resultRelationDesc);
}
else
{
ItemPointerData lockedtid;
/*
* If we generate a new candidate tuple after EvalPlanQual testing, we
* must loop back here to try again. (We don't need to redo triggers,
* however. If there are any BEFORE triggers then trigger.c will have
* done table_tuple_lock to lock the correct tuple, so there's no need
* to do them again.)
*/
redo_act:
lockedtid = *tupleid;
result = ExecUpdateAct(context, resultRelInfo, tupleid, oldtuple, slot,
canSetTag, &updateCxt);
/*
* If ExecUpdateAct reports that a cross-partition update was done,
* then the RETURNING tuple (if any) has been projected and there's
* nothing else for us to do.
*/
if (updateCxt.crossPartUpdate)
return context->cpUpdateReturningSlot;
switch (result)
{
case TM_SelfModified:
/*
* 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 (context->tmfd.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 TM_Ok:
break;
case TM_Updated:
{
TupleTableSlot *inputslot;
TupleTableSlot *epqslot;
TupleTableSlot *oldSlot;
if (IsolationUsesXactSnapshot())
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent update")));
/*
* Already know that we're going to need to do EPQ, so
* fetch tuple directly into the right slot.
*/
inputslot = EvalPlanQualSlot(context->epqstate, resultRelationDesc,
resultRelInfo->ri_RangeTableIndex);
result = table_tuple_lock(resultRelationDesc, tupleid,
estate->es_snapshot,
inputslot, estate->es_output_cid,
updateCxt.lockmode, LockWaitBlock,
TUPLE_LOCK_FLAG_FIND_LAST_VERSION,
&context->tmfd);
switch (result)
{
case TM_Ok:
Assert(context->tmfd.traversed);
epqslot = EvalPlanQual(context->epqstate,
resultRelationDesc,
resultRelInfo->ri_RangeTableIndex,
inputslot);
if (TupIsNull(epqslot))
/* Tuple not passing quals anymore, exiting... */
return NULL;
/* Make sure ri_oldTupleSlot is initialized. */
if (unlikely(!resultRelInfo->ri_projectNewInfoValid))
ExecInitUpdateProjection(context->mtstate,
resultRelInfo);
if (resultRelInfo->ri_needLockTagTuple)
{
UnlockTuple(resultRelationDesc,
&lockedtid, InplaceUpdateTupleLock);
LockTuple(resultRelationDesc,
tupleid, InplaceUpdateTupleLock);
}
/* Fetch the most recent version of old tuple. */
oldSlot = resultRelInfo->ri_oldTupleSlot;
if (!table_tuple_fetch_row_version(resultRelationDesc,
tupleid,
SnapshotAny,
oldSlot))
elog(ERROR, "failed to fetch tuple being updated");
slot = ExecGetUpdateNewTuple(resultRelInfo,
epqslot, oldSlot);
goto redo_act;
case TM_Deleted:
/* tuple already deleted; nothing to do */
return NULL;
case TM_SelfModified:
/*
* This can be reached when following an update
* chain from a tuple updated by another session,
* reaching a tuple that was already updated in
* this transaction. If previously modified by
* this command, ignore the redundant update,
* otherwise error out.
*
* See also TM_SelfModified response to
* table_tuple_update() above.
*/
if (context->tmfd.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.")));
return NULL;
default:
/* see table_tuple_lock call in ExecDelete() */
elog(ERROR, "unexpected table_tuple_lock status: %u",
result);
return NULL;
}
}
break;
case TM_Deleted:
if (IsolationUsesXactSnapshot())
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent delete")));
/* tuple already deleted; nothing to do */
return NULL;
default:
elog(ERROR, "unrecognized table_tuple_update status: %u",
result);
return NULL;
}
}
if (canSetTag)
(estate->es_processed)++;
ExecUpdateEpilogue(context, &updateCxt, resultRelInfo, tupleid, oldtuple,
slot);
/* Process RETURNING if present */
if (resultRelInfo->ri_projectReturning)
return ExecProcessReturning(resultRelInfo, slot, context->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 we're done (with or without an update), or false if
* the caller must retry the INSERT from scratch.
*/
static bool
ExecOnConflictUpdate(ModifyTableContext *context,
ResultRelInfo *resultRelInfo,
ItemPointer conflictTid,
TupleTableSlot *excludedSlot,
bool canSetTag,
TupleTableSlot **returning)
{
ModifyTableState *mtstate = context->mtstate;
ExprContext *econtext = mtstate->ps.ps_ExprContext;
Relation relation = resultRelInfo->ri_RelationDesc;
ExprState *onConflictSetWhere = resultRelInfo->ri_onConflict->oc_WhereClause;
TupleTableSlot *existing = resultRelInfo->ri_onConflict->oc_Existing;
TM_FailureData tmfd;
LockTupleMode lockmode;
TM_Result test;
Datum xminDatum;
TransactionId xmin;
bool isnull;
/*
* Parse analysis should have blocked ON CONFLICT for all system
* relations, which includes these. There's no fundamental obstacle to
* supporting this; we'd just need to handle LOCKTAG_TUPLE like the other
* ExecUpdate() caller.
*/
Assert(!resultRelInfo->ri_needLockTagTuple);
/* Determine lock mode to use */
lockmode = ExecUpdateLockMode(context->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.
*/
test = table_tuple_lock(relation, conflictTid,
context->estate->es_snapshot,
existing, context->estate->es_output_cid,
lockmode, LockWaitBlock, 0,
&tmfd);
switch (test)
{
case TM_Ok:
/* success! */
break;
case TM_Invisible:
/*
* 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() TM_SelfModified
* 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 the SQL standard similarly
* specifies that for SQL MERGE, an exception must be raised in
* the event of an attempt to update the same row twice.
*/
xminDatum = slot_getsysattr(existing,
MinTransactionIdAttributeNumber,
&isnull);
Assert(!isnull);
xmin = DatumGetTransactionId(xminDatum);
if (TransactionIdIsCurrentTransactionId(xmin))
ereport(ERROR,
(errcode(ERRCODE_CARDINALITY_VIOLATION),
/* translator: %s is a SQL command name */
errmsg("%s command cannot affect row a second time",
"ON CONFLICT DO UPDATE"),
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");
break;
case TM_SelfModified:
/*
* 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");
break;
case TM_Updated:
if (IsolationUsesXactSnapshot())
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent update")));
/*
* As long as we don't support an UPDATE of INSERT ON CONFLICT for
* a partitioned table we shouldn't reach to a case where tuple to
* be lock is moved to another partition due to concurrent update
* of the partition key.
*/
Assert(!ItemPointerIndicatesMovedPartitions(&tmfd.ctid));
/*
* 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.
*/
ExecClearTuple(existing);
return false;
case TM_Deleted:
if (IsolationUsesXactSnapshot())
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent delete")));
/* see TM_Updated case */
Assert(!ItemPointerIndicatesMovedPartitions(&tmfd.ctid));
ExecClearTuple(existing);
return false;
default:
elog(ERROR, "unrecognized table_tuple_lock status: %u", test);
}
/* Success, the tuple is locked. */
/*
* 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.
*/
ExecCheckTupleVisible(context->estate, relation, existing);
/*
* 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 = existing;
econtext->ecxt_innertuple = excludedSlot;
econtext->ecxt_outertuple = NULL;
if (!ExecQual(onConflictSetWhere, econtext))
{
ExecClearTuple(existing); /* see return below */
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,
existing,
mtstate->ps.state);
}
/* Project the new tuple version */
ExecProject(resultRelInfo->ri_onConflict->oc_ProjInfo);
/*
* Note that it is possible that the target tuple has been modified in
* this session, after the above table_tuple_lock. 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(context, resultRelInfo,
conflictTid, NULL,
resultRelInfo->ri_onConflict->oc_ProjSlot,
canSetTag);
/*
* Clear out existing tuple, as there might not be another conflict among
* the next input rows. Don't want to hold resources till the end of the
* query.
*/
ExecClearTuple(existing);
return true;
}
/*
* Perform MERGE.
*/
static TupleTableSlot *
ExecMerge(ModifyTableContext *context, ResultRelInfo *resultRelInfo,
ItemPointer tupleid, HeapTuple oldtuple, bool canSetTag)
{
TupleTableSlot *rslot = NULL;
bool matched;
/*-----
* If we are dealing with a WHEN MATCHED case, tupleid or oldtuple is
* valid, depending on whether the result relation is a table or a view.
* We execute the first action for which the additional WHEN MATCHED AND
* quals pass. If an action without quals is found, that action is
* executed.
*
* Similarly, in the WHEN NOT MATCHED BY SOURCE case, tupleid or oldtuple
* is valid, and we look at the given WHEN NOT MATCHED BY SOURCE actions
* in sequence until one passes. This is almost identical to the WHEN
* MATCHED case, and both cases are handled by ExecMergeMatched().
*
* Finally, in the WHEN NOT MATCHED [BY TARGET] case, both tupleid and
* oldtuple are invalid, and we look at the given WHEN NOT MATCHED [BY
* TARGET] actions in sequence until one passes.
*
* Things get interesting in case of concurrent update/delete of the
* target tuple. Such concurrent update/delete is detected while we are
* executing a WHEN MATCHED or WHEN NOT MATCHED BY SOURCE action.
*
* A concurrent update can:
*
* 1. modify the target tuple so that the results from checking any
* additional quals attached to WHEN MATCHED or WHEN NOT MATCHED BY
* SOURCE actions potentially change, but the result from the join
* quals does not change.
*
* In this case, we are still dealing with the same kind of match
* (MATCHED or NOT MATCHED BY SOURCE). We recheck the same list of
* actions from the start and choose the first one that satisfies the
* new target tuple.
*
* 2. modify the target tuple in the WHEN MATCHED case so that the join
* quals no longer pass and hence the source and target tuples no
* longer match.
*
* In this case, we are now dealing with a NOT MATCHED case, and we
* process both WHEN NOT MATCHED BY SOURCE and WHEN NOT MATCHED [BY
* TARGET] actions. First ExecMergeMatched() processes the list of
* WHEN NOT MATCHED BY SOURCE actions in sequence until one passes,
* then ExecMergeNotMatched() processes any WHEN NOT MATCHED [BY
* TARGET] actions in sequence until one passes. Thus we may execute
* two actions; one of each kind.
*
* Thus we support concurrent updates that turn MATCHED candidate rows
* into NOT MATCHED rows. However, we do not attempt to support cases
* that would turn NOT MATCHED rows into MATCHED rows, or which would
* cause a target row to match a different source row.
*
* A concurrent delete changes a WHEN MATCHED case to WHEN NOT MATCHED
* [BY TARGET].
*
* ExecMergeMatched() takes care of following the update chain and
* re-finding the qualifying WHEN MATCHED or WHEN NOT MATCHED BY SOURCE
* action, as long as the target tuple still exists. If the target tuple
* gets deleted or a concurrent update causes the join quals to fail, it
* returns a matched status of false and we call ExecMergeNotMatched().
* Given that ExecMergeMatched() always makes progress by following the
* update chain and we never switch from ExecMergeNotMatched() to
* ExecMergeMatched(), there is no risk of a livelock.
*/
matched = tupleid != NULL || oldtuple != NULL;
if (matched)
rslot = ExecMergeMatched(context, resultRelInfo, tupleid, oldtuple,
canSetTag, &matched);
/*
* Deal with the NOT MATCHED case (either a NOT MATCHED tuple from the
* join, or a previously MATCHED tuple for which ExecMergeMatched() set
* "matched" to false, indicating that it no longer matches).
*/
if (!matched)
{
/*
* If a concurrent update turned a MATCHED case into a NOT MATCHED
* case, and we have both WHEN NOT MATCHED BY SOURCE and WHEN NOT
* MATCHED [BY TARGET] actions, and there is a RETURNING clause,
* ExecMergeMatched() may have already executed a WHEN NOT MATCHED BY
* SOURCE action, and computed the row to return. If so, we cannot
* execute a WHEN NOT MATCHED [BY TARGET] action now, so mark it as
* pending (to be processed on the next call to ExecModifyTable()).
* Otherwise, just process the action now.
*/
if (rslot == NULL)
rslot = ExecMergeNotMatched(context, resultRelInfo, canSetTag);
else
context->mtstate->mt_merge_pending_not_matched = context->planSlot;
}
return rslot;
}
/*
* Check and execute the first qualifying MATCHED or NOT MATCHED BY SOURCE
* action, depending on whether the join quals are satisfied. If the target
* relation is a table, the current target tuple is identified by tupleid.
* Otherwise, if the target relation is a view, oldtuple is the current target
* tuple from the view.
*
* We start from the first WHEN MATCHED or WHEN NOT MATCHED BY SOURCE action
* and check if the WHEN quals pass, if any. If the WHEN quals for the first
* action do not pass, we check the second, then the third and so on. If we
* reach the end without finding a qualifying action, we return NULL.
* Otherwise, we execute the qualifying action and return its RETURNING
* result, if any, or NULL.
*
* On entry, "*matched" is assumed to be true. If a concurrent update or
* delete is detected that causes the join quals to no longer pass, we set it
* to false, indicating that the caller should process any NOT MATCHED [BY
* TARGET] actions.
*
* After a concurrent update, we restart from the first action to look for a
* new qualifying action to execute. If the join quals originally passed, and
* the concurrent update caused them to no longer pass, then we switch from
* the MATCHED to the NOT MATCHED BY SOURCE list of actions before restarting
* (and setting "*matched" to false). As a result we may execute a WHEN NOT
* MATCHED BY SOURCE action, and set "*matched" to false, causing the caller
* to also execute a WHEN NOT MATCHED [BY TARGET] action.
*/
static TupleTableSlot *
ExecMergeMatched(ModifyTableContext *context, ResultRelInfo *resultRelInfo,
ItemPointer tupleid, HeapTuple oldtuple, bool canSetTag,
bool *matched)
{
ModifyTableState *mtstate = context->mtstate;
List **mergeActions = resultRelInfo->ri_MergeActions;
ItemPointerData lockedtid;
List *actionStates;
TupleTableSlot *newslot = NULL;
TupleTableSlot *rslot = NULL;
EState *estate = context->estate;
ExprContext *econtext = mtstate->ps.ps_ExprContext;
bool isNull;
EPQState *epqstate = &mtstate->mt_epqstate;
ListCell *l;
/* Expect matched to be true on entry */
Assert(*matched);
/*
* If there are no WHEN MATCHED or WHEN NOT MATCHED BY SOURCE actions, we
* are done.
*/
if (mergeActions[MERGE_WHEN_MATCHED] == NIL &&
mergeActions[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] == NIL)
return NULL;
/*
* Make tuple and any needed join variables available to ExecQual and
* ExecProject. The target's existing tuple is installed in the scantuple.
* This target relation's slot is required only in the case of a MATCHED
* or NOT MATCHED BY SOURCE tuple and UPDATE/DELETE actions.
*/
econtext->ecxt_scantuple = resultRelInfo->ri_oldTupleSlot;
econtext->ecxt_innertuple = context->planSlot;
econtext->ecxt_outertuple = NULL;
/*
* This routine is only invoked for matched target rows, so we should
* either have the tupleid of the target row, or an old tuple from the
* target wholerow junk attr.
*/
Assert(tupleid != NULL || oldtuple != NULL);
ItemPointerSetInvalid(&lockedtid);
if (oldtuple != NULL)
{
Assert(!resultRelInfo->ri_needLockTagTuple);
ExecForceStoreHeapTuple(oldtuple, resultRelInfo->ri_oldTupleSlot,
false);
}
else
{
if (resultRelInfo->ri_needLockTagTuple)
{
/*
* This locks even for CMD_DELETE, for CMD_NOTHING, and for tuples
* that don't match mas_whenqual. MERGE on system catalogs is a
* minor use case, so don't bother optimizing those.
*/
LockTuple(resultRelInfo->ri_RelationDesc, tupleid,
InplaceUpdateTupleLock);
lockedtid = *tupleid;
}
if (!table_tuple_fetch_row_version(resultRelInfo->ri_RelationDesc,
tupleid,
SnapshotAny,
resultRelInfo->ri_oldTupleSlot))
elog(ERROR, "failed to fetch the target tuple");
}
/*
* Test the join condition. If it's satisfied, perform a MATCHED action.
* Otherwise, perform a NOT MATCHED BY SOURCE action.
*
* Note that this join condition will be NULL if there are no NOT MATCHED
* BY SOURCE actions --- see transform_MERGE_to_join(). In that case, we
* need only consider MATCHED actions here.
*/
if (ExecQual(resultRelInfo->ri_MergeJoinCondition, econtext))
actionStates = mergeActions[MERGE_WHEN_MATCHED];
else
actionStates = mergeActions[MERGE_WHEN_NOT_MATCHED_BY_SOURCE];
lmerge_matched:
foreach(l, actionStates)
{
MergeActionState *relaction = (MergeActionState *) lfirst(l);
CmdType commandType = relaction->mas_action->commandType;
TM_Result result;
UpdateContext updateCxt = {0};
/*
* Test condition, if any.
*
* In the absence of any condition, we perform the action
* unconditionally (no need to check separately since ExecQual() will
* return true if there are no conditions to evaluate).
*/
if (!ExecQual(relaction->mas_whenqual, econtext))
continue;
/*
* Check if the existing target tuple meets the USING checks of
* UPDATE/DELETE RLS policies. If those checks fail, we throw an
* error.
*
* The WITH CHECK quals for UPDATE RLS policies are applied in
* ExecUpdateAct() and hence we need not do anything special to handle
* them.
*
* NOTE: We must do this after WHEN quals are evaluated, so that we
* check policies only when they matter.
*/
if (resultRelInfo->ri_WithCheckOptions && commandType != CMD_NOTHING)
{
ExecWithCheckOptions(commandType == CMD_UPDATE ?
WCO_RLS_MERGE_UPDATE_CHECK : WCO_RLS_MERGE_DELETE_CHECK,
resultRelInfo,
resultRelInfo->ri_oldTupleSlot,
context->mtstate->ps.state);
}
/* Perform stated action */
switch (commandType)
{
case CMD_UPDATE:
/*
* Project the output tuple, and use that to update the table.
* We don't need to filter out junk attributes, because the
* UPDATE action's targetlist doesn't have any.
*/
newslot = ExecProject(relaction->mas_proj);
mtstate->mt_merge_action = relaction;
if (!ExecUpdatePrologue(context, resultRelInfo,
tupleid, NULL, newslot, &result))
{
if (result == TM_Ok)
goto out; /* "do nothing" */
break; /* concurrent update/delete */
}
/* INSTEAD OF ROW UPDATE Triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->trig_update_instead_row)
{
if (!ExecIRUpdateTriggers(estate, resultRelInfo,
oldtuple, newslot))
goto out; /* "do nothing" */
}
else
{
/* checked ri_needLockTagTuple above */
Assert(oldtuple == NULL);
result = ExecUpdateAct(context, resultRelInfo, tupleid,
NULL, newslot, canSetTag,
&updateCxt);
/*
* As in ExecUpdate(), if ExecUpdateAct() reports that a
* cross-partition update was done, then there's nothing
* else for us to do --- the UPDATE has been turned into a
* DELETE and an INSERT, and we must not perform any of
* the usual post-update tasks. Also, the RETURNING tuple
* (if any) has been projected, so we can just return
* that.
*/
if (updateCxt.crossPartUpdate)
{
mtstate->mt_merge_updated += 1;
rslot = context->cpUpdateReturningSlot;
goto out;
}
}
if (result == TM_Ok)
{
ExecUpdateEpilogue(context, &updateCxt, resultRelInfo,
tupleid, NULL, newslot);
mtstate->mt_merge_updated += 1;
}
break;
case CMD_DELETE:
mtstate->mt_merge_action = relaction;
if (!ExecDeletePrologue(context, resultRelInfo, tupleid,
NULL, NULL, &result))
{
if (result == TM_Ok)
goto out; /* "do nothing" */
break; /* concurrent update/delete */
}
/* INSTEAD OF ROW DELETE Triggers */
if (resultRelInfo->ri_TrigDesc &&
resultRelInfo->ri_TrigDesc->trig_delete_instead_row)
{
if (!ExecIRDeleteTriggers(estate, resultRelInfo,
oldtuple))
goto out; /* "do nothing" */
}
else
{
/* checked ri_needLockTagTuple above */
Assert(oldtuple == NULL);
result = ExecDeleteAct(context, resultRelInfo, tupleid,
false);
}
if (result == TM_Ok)
{
ExecDeleteEpilogue(context, resultRelInfo, tupleid, NULL,
false);
mtstate->mt_merge_deleted += 1;
}
break;
case CMD_NOTHING:
/* Doing nothing is always OK */
result = TM_Ok;
break;
default:
elog(ERROR, "unknown action in MERGE WHEN clause");
}
switch (result)
{
case TM_Ok:
/* all good; perform final actions */
if (canSetTag && commandType != CMD_NOTHING)
(estate->es_processed)++;
break;
case TM_SelfModified:
/*
* 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 explicitly disallowed by
* the SQL standard for MERGE, which insists that the MERGE
* join condition should not join a target row to more than
* one source row.
*
* 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 MERGE action, but it is equally
* unsafe to proceed. We don't want to discard the original
* MERGE action while keeping the triggered actions based on
* it; and it would be no better to allow the original MERGE
* action while discarding the updates that it triggered. So
* throwing an error is the only safe course.
*/
if (context->tmfd.cmax != estate->es_output_cid)
ereport(ERROR,
(errcode(ERRCODE_TRIGGERED_DATA_CHANGE_VIOLATION),
errmsg("tuple to be updated or deleted 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.")));
if (TransactionIdIsCurrentTransactionId(context->tmfd.xmax))
ereport(ERROR,
(errcode(ERRCODE_CARDINALITY_VIOLATION),
/* translator: %s is a SQL command name */
errmsg("%s command cannot affect row a second time",
"MERGE"),
errhint("Ensure that not more than one source row matches any one target row.")));
/* This shouldn't happen */
elog(ERROR, "attempted to update or delete invisible tuple");
break;
case TM_Deleted:
if (IsolationUsesXactSnapshot())
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent delete")));
/*
* If the tuple was already deleted, set matched to false to
* let caller handle it under NOT MATCHED [BY TARGET] clauses.
*/
*matched = false;
goto out;
case TM_Updated:
{
bool was_matched;
Relation resultRelationDesc;
TupleTableSlot *epqslot,
*inputslot;
LockTupleMode lockmode;
/*
* The target tuple was concurrently updated by some other
* transaction. If we are currently processing a MATCHED
* action, use EvalPlanQual() with the new version of the
* tuple and recheck the join qual, to detect a change
* from the MATCHED to the NOT MATCHED cases. If we are
* already processing a NOT MATCHED BY SOURCE action, we
* skip this (cannot switch from NOT MATCHED BY SOURCE to
* MATCHED).
*/
was_matched = relaction->mas_action->matchKind == MERGE_WHEN_MATCHED;
resultRelationDesc = resultRelInfo->ri_RelationDesc;
lockmode = ExecUpdateLockMode(estate, resultRelInfo);
if (was_matched)
inputslot = EvalPlanQualSlot(epqstate, resultRelationDesc,
resultRelInfo->ri_RangeTableIndex);
else
inputslot = resultRelInfo->ri_oldTupleSlot;
result = table_tuple_lock(resultRelationDesc, tupleid,
estate->es_snapshot,
inputslot, estate->es_output_cid,
lockmode, LockWaitBlock,
TUPLE_LOCK_FLAG_FIND_LAST_VERSION,
&context->tmfd);
switch (result)
{
case TM_Ok:
/*
* If the tuple was updated and migrated to
* another partition concurrently, the current
* MERGE implementation can't follow. There's
* probably a better way to handle this case, but
* it'd require recognizing the relation to which
* the tuple moved, and setting our current
* resultRelInfo to that.
*/
if (ItemPointerIndicatesMovedPartitions(&context->tmfd.ctid))
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("tuple to be merged was already moved to another partition due to concurrent update")));
/*
* If this was a MATCHED case, use EvalPlanQual()
* to recheck the join condition.
*/
if (was_matched)
{
epqslot = EvalPlanQual(epqstate,
resultRelationDesc,
resultRelInfo->ri_RangeTableIndex,
inputslot);
/*
* If the subplan didn't return a tuple, then
* we must be dealing with an inner join for
* which the join condition no longer matches.
* This can only happen if there are no NOT
* MATCHED actions, and so there is nothing
* more to do.
*/
if (TupIsNull(epqslot))
goto out;
/*
* If we got a NULL ctid from the subplan, the
* join quals no longer pass and we switch to
* the NOT MATCHED BY SOURCE case.
*/
(void) ExecGetJunkAttribute(epqslot,
resultRelInfo->ri_RowIdAttNo,
&isNull);
if (isNull)
*matched = false;
/*
* Otherwise, recheck the join quals to see if
* we need to switch to the NOT MATCHED BY
* SOURCE case.
*/
if (resultRelInfo->ri_needLockTagTuple)
{
if (ItemPointerIsValid(&lockedtid))
UnlockTuple(resultRelInfo->ri_RelationDesc, &lockedtid,
InplaceUpdateTupleLock);
LockTuple(resultRelInfo->ri_RelationDesc, &context->tmfd.ctid,
InplaceUpdateTupleLock);
lockedtid = context->tmfd.ctid;
}
if (!table_tuple_fetch_row_version(resultRelationDesc,
&context->tmfd.ctid,
SnapshotAny,
resultRelInfo->ri_oldTupleSlot))
elog(ERROR, "failed to fetch the target tuple");
if (*matched)
*matched = ExecQual(resultRelInfo->ri_MergeJoinCondition,
econtext);
/* Switch lists, if necessary */
if (!*matched)
actionStates = mergeActions[MERGE_WHEN_NOT_MATCHED_BY_SOURCE];
}
/*
* Loop back and process the MATCHED or NOT
* MATCHED BY SOURCE actions from the start.
*/
goto lmerge_matched;
case TM_Deleted:
/*
* tuple already deleted; tell caller to run NOT
* MATCHED [BY TARGET] actions
*/
*matched = false;
goto out;
case TM_SelfModified:
/*
* This can be reached when following an update
* chain from a tuple updated by another session,
* reaching a tuple that was already updated or
* deleted by the current command, or by a later
* command in the current transaction. As above,
* this should always be treated as an error.
*/
if (context->tmfd.cmax != estate->es_output_cid)
ereport(ERROR,
(errcode(ERRCODE_TRIGGERED_DATA_CHANGE_VIOLATION),
errmsg("tuple to be updated or deleted 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.")));
if (TransactionIdIsCurrentTransactionId(context->tmfd.xmax))
ereport(ERROR,
(errcode(ERRCODE_CARDINALITY_VIOLATION),
/* translator: %s is a SQL command name */
errmsg("%s command cannot affect row a second time",
"MERGE"),
errhint("Ensure that not more than one source row matches any one target row.")));
/* This shouldn't happen */
elog(ERROR, "attempted to update or delete invisible tuple");
goto out;
default:
/* see table_tuple_lock call in ExecDelete() */
elog(ERROR, "unexpected table_tuple_lock status: %u",
result);
goto out;
}
}
case TM_Invisible:
case TM_WouldBlock:
case TM_BeingModified:
/* these should not occur */
elog(ERROR, "unexpected tuple operation result: %d", result);
break;
}
/* Process RETURNING if present */
if (resultRelInfo->ri_projectReturning)
{
switch (commandType)
{
case CMD_UPDATE:
rslot = ExecProcessReturning(resultRelInfo, newslot,
context->planSlot);
break;
case CMD_DELETE:
rslot = ExecProcessReturning(resultRelInfo,
resultRelInfo->ri_oldTupleSlot,
context->planSlot);
break;
case CMD_NOTHING:
break;
default:
elog(ERROR, "unrecognized commandType: %d",
(int) commandType);
}
}
/*
* We've activated one of the WHEN clauses, so we don't search
* further. This is required behaviour, not an optimization.
*/
break;
}
/*
* Successfully executed an action or no qualifying action was found.
*/
out:
if (ItemPointerIsValid(&lockedtid))
UnlockTuple(resultRelInfo->ri_RelationDesc, &lockedtid,
InplaceUpdateTupleLock);
return rslot;
}
/*
* Execute the first qualifying NOT MATCHED [BY TARGET] action.
*/
static TupleTableSlot *
ExecMergeNotMatched(ModifyTableContext *context, ResultRelInfo *resultRelInfo,
bool canSetTag)
{
ModifyTableState *mtstate = context->mtstate;
ExprContext *econtext = mtstate->ps.ps_ExprContext;
List *actionStates;
TupleTableSlot *rslot = NULL;
ListCell *l;
/*
* For INSERT actions, the root relation's merge action is OK since the
* INSERT's targetlist and the WHEN conditions can only refer to the
* source relation and hence it does not matter which result relation we
* work with.
*
* XXX does this mean that we can avoid creating copies of actionStates on
* partitioned tables, for not-matched actions?
*/
actionStates = resultRelInfo->ri_MergeActions[MERGE_WHEN_NOT_MATCHED_BY_TARGET];
/*
* Make source tuple available to ExecQual and ExecProject. We don't need
* the target tuple, since the WHEN quals and targetlist can't refer to
* the target columns.
*/
econtext->ecxt_scantuple = NULL;
econtext->ecxt_innertuple = context->planSlot;
econtext->ecxt_outertuple = NULL;
foreach(l, actionStates)
{
MergeActionState *action = (MergeActionState *) lfirst(l);
CmdType commandType = action->mas_action->commandType;
TupleTableSlot *newslot;
/*
* Test condition, if any.
*
* In the absence of any condition, we perform the action
* unconditionally (no need to check separately since ExecQual() will
* return true if there are no conditions to evaluate).
*/
if (!ExecQual(action->mas_whenqual, econtext))
continue;
/* Perform stated action */
switch (commandType)
{
case CMD_INSERT:
/*
* Project the tuple. In case of a partitioned table, the
* projection was already built to use the root's descriptor,
* so we don't need to map the tuple here.
*/
newslot = ExecProject(action->mas_proj);
mtstate->mt_merge_action = action;
rslot = ExecInsert(context, mtstate->rootResultRelInfo,
newslot, canSetTag, NULL, NULL);
mtstate->mt_merge_inserted += 1;
break;
case CMD_NOTHING:
/* Do nothing */
break;
default:
elog(ERROR, "unknown action in MERGE WHEN NOT MATCHED clause");
}
/*
* We've activated one of the WHEN clauses, so we don't search
* further. This is required behaviour, not an optimization.
*/
break;
}
return rslot;
}
/*
* Initialize state for execution of MERGE.
*/
void
ExecInitMerge(ModifyTableState *mtstate, EState *estate)
{
ModifyTable *node = (ModifyTable *) mtstate->ps.plan;
ResultRelInfo *rootRelInfo = mtstate->rootResultRelInfo;
ResultRelInfo *resultRelInfo;
ExprContext *econtext;
ListCell *lc;
int i;
if (node->mergeActionLists == NIL)
return;
mtstate->mt_merge_subcommands = 0;
if (mtstate->ps.ps_ExprContext == NULL)
ExecAssignExprContext(estate, &mtstate->ps);
econtext = mtstate->ps.ps_ExprContext;
/*
* Create a MergeActionState for each action on the mergeActionList and
* add it to either a list of matched actions or not-matched actions.
*
* Similar logic appears in ExecInitPartitionInfo(), so if changing
* anything here, do so there too.
*/
i = 0;
foreach(lc, node->mergeActionLists)
{
List *mergeActionList = lfirst(lc);
Node *joinCondition;
TupleDesc relationDesc;
ListCell *l;
joinCondition = (Node *) list_nth(node->mergeJoinConditions, i);
resultRelInfo = mtstate->resultRelInfo + i;
i++;
relationDesc = RelationGetDescr(resultRelInfo->ri_RelationDesc);
/* initialize slots for MERGE fetches from this rel */
if (unlikely(!resultRelInfo->ri_projectNewInfoValid))
ExecInitMergeTupleSlots(mtstate, resultRelInfo);
/* initialize state for join condition checking */
resultRelInfo->ri_MergeJoinCondition =
ExecInitQual((List *) joinCondition, &mtstate->ps);
foreach(l, mergeActionList)
{
MergeAction *action = (MergeAction *) lfirst(l);
MergeActionState *action_state;
TupleTableSlot *tgtslot;
TupleDesc tgtdesc;
/*
* Build action merge state for this rel. (For partitions,
* equivalent code exists in ExecInitPartitionInfo.)
*/
action_state = makeNode(MergeActionState);
action_state->mas_action = action;
action_state->mas_whenqual = ExecInitQual((List *) action->qual,
&mtstate->ps);
/*
* We create three lists - one for each MergeMatchKind - and stick
* the MergeActionState into the appropriate list.
*/
resultRelInfo->ri_MergeActions[action->matchKind] =
lappend(resultRelInfo->ri_MergeActions[action->matchKind],
action_state);
switch (action->commandType)
{
case CMD_INSERT:
/* INSERT actions always use rootRelInfo */
ExecCheckPlanOutput(rootRelInfo->ri_RelationDesc,
action->targetList);
/*
* If the MERGE targets a partitioned table, any INSERT
* actions must be routed through it, not the child
* relations. Initialize the routing struct and the root
* table's "new" tuple slot for that, if not already done.
* The projection we prepare, for all relations, uses the
* root relation descriptor, and targets the plan's root
* slot. (This is consistent with the fact that we
* checked the plan output to match the root relation,
* above.)
*/
if (rootRelInfo->ri_RelationDesc->rd_rel->relkind ==
RELKIND_PARTITIONED_TABLE)
{
if (mtstate->mt_partition_tuple_routing == NULL)
{
/*
* Initialize planstate for routing if not already
* done.
*
* Note that the slot is managed as a standalone
* slot belonging to ModifyTableState, so we pass
* NULL for the 2nd argument.
*/
mtstate->mt_root_tuple_slot =
table_slot_create(rootRelInfo->ri_RelationDesc,
NULL);
mtstate->mt_partition_tuple_routing =
ExecSetupPartitionTupleRouting(estate,
rootRelInfo->ri_RelationDesc);
}
tgtslot = mtstate->mt_root_tuple_slot;
tgtdesc = RelationGetDescr(rootRelInfo->ri_RelationDesc);
}
else
{
/*
* If the MERGE targets an inherited table, we insert
* into the root table, so we must initialize its
* "new" tuple slot, if not already done, and use its
* relation descriptor for the projection.
*
* For non-inherited tables, rootRelInfo and
* resultRelInfo are the same, and the "new" tuple
* slot will already have been initialized.
*/
if (rootRelInfo->ri_newTupleSlot == NULL)
rootRelInfo->ri_newTupleSlot =
table_slot_create(rootRelInfo->ri_RelationDesc,
&estate->es_tupleTable);
tgtslot = rootRelInfo->ri_newTupleSlot;
tgtdesc = RelationGetDescr(rootRelInfo->ri_RelationDesc);
}
action_state->mas_proj =
ExecBuildProjectionInfo(action->targetList, econtext,
tgtslot,
&mtstate->ps,
tgtdesc);
mtstate->mt_merge_subcommands |= MERGE_INSERT;
break;
case CMD_UPDATE:
action_state->mas_proj =
ExecBuildUpdateProjection(action->targetList,
true,
action->updateColnos,
relationDesc,
econtext,
resultRelInfo->ri_newTupleSlot,
&mtstate->ps);
mtstate->mt_merge_subcommands |= MERGE_UPDATE;
break;
case CMD_DELETE:
mtstate->mt_merge_subcommands |= MERGE_DELETE;
break;
case CMD_NOTHING:
break;
default:
elog(ERROR, "unknown action in MERGE WHEN clause");
break;
}
}
}
/*
* If the MERGE targets an inherited table, any INSERT actions will use
* rootRelInfo, and rootRelInfo will not be in the resultRelInfo array.
* Therefore we must initialize its WITH CHECK OPTION constraints and
* RETURNING projection, as ExecInitModifyTable did for the resultRelInfo
* entries.
*
* Note that the planner does not build a withCheckOptionList or
* returningList for the root relation, but as in ExecInitPartitionInfo,
* we can use the first resultRelInfo entry as a reference to calculate
* the attno's for the root table.
*/
if (rootRelInfo != mtstate->resultRelInfo &&
rootRelInfo->ri_RelationDesc->rd_rel->relkind != RELKIND_PARTITIONED_TABLE &&
(mtstate->mt_merge_subcommands & MERGE_INSERT) != 0)
{
Relation rootRelation = rootRelInfo->ri_RelationDesc;
Relation firstResultRel = mtstate->resultRelInfo[0].ri_RelationDesc;
int firstVarno = mtstate->resultRelInfo[0].ri_RangeTableIndex;
AttrMap *part_attmap = NULL;
bool found_whole_row;
if (node->withCheckOptionLists != NIL)
{
List *wcoList;
List *wcoExprs = NIL;
/* There should be as many WCO lists as result rels */
Assert(list_length(node->withCheckOptionLists) ==
list_length(node->resultRelations));
/*
* Use the first WCO list as a reference. In the most common case,
* this will be for the same relation as rootRelInfo, and so there
* will be no need to adjust its attno's.
*/
wcoList = linitial(node->withCheckOptionLists);
if (rootRelation != firstResultRel)
{
/* Convert any Vars in it to contain the root's attno's */
part_attmap =
build_attrmap_by_name(RelationGetDescr(rootRelation),
RelationGetDescr(firstResultRel),
false);
wcoList = (List *)
map_variable_attnos((Node *) wcoList,
firstVarno, 0,
part_attmap,
RelationGetForm(rootRelation)->reltype,
&found_whole_row);
}
foreach(lc, wcoList)
{
WithCheckOption *wco = lfirst_node(WithCheckOption, lc);
ExprState *wcoExpr = ExecInitQual(castNode(List, wco->qual),
&mtstate->ps);
wcoExprs = lappend(wcoExprs, wcoExpr);
}
rootRelInfo->ri_WithCheckOptions = wcoList;
rootRelInfo->ri_WithCheckOptionExprs = wcoExprs;
}
if (node->returningLists != NIL)
{
List *returningList;
/* There should be as many returning lists as result rels */
Assert(list_length(node->returningLists) ==
list_length(node->resultRelations));
/*
* Use the first returning list as a reference. In the most common
* case, this will be for the same relation as rootRelInfo, and so
* there will be no need to adjust its attno's.
*/
returningList = linitial(node->returningLists);
if (rootRelation != firstResultRel)
{
/* Convert any Vars in it to contain the root's attno's */
if (part_attmap == NULL)
part_attmap =
build_attrmap_by_name(RelationGetDescr(rootRelation),
RelationGetDescr(firstResultRel),
false);
returningList = (List *)
map_variable_attnos((Node *) returningList,
firstVarno, 0,
part_attmap,
RelationGetForm(rootRelation)->reltype,
&found_whole_row);
}
rootRelInfo->ri_returningList = returningList;
/* Initialize the RETURNING projection */
rootRelInfo->ri_projectReturning =
ExecBuildProjectionInfo(returningList, econtext,
mtstate->ps.ps_ResultTupleSlot,
&mtstate->ps,
RelationGetDescr(rootRelation));
}
}
}
/*
* Initializes the tuple slots in a ResultRelInfo for any MERGE action.
*
* We mark 'projectNewInfoValid' even though the projections themselves
* are not initialized here.
*/
void
ExecInitMergeTupleSlots(ModifyTableState *mtstate,
ResultRelInfo *resultRelInfo)
{
EState *estate = mtstate->ps.state;
Assert(!resultRelInfo->ri_projectNewInfoValid);
resultRelInfo->ri_oldTupleSlot =
table_slot_create(resultRelInfo->ri_RelationDesc,
&estate->es_tupleTable);
resultRelInfo->ri_newTupleSlot =
table_slot_create(resultRelInfo->ri_RelationDesc,
&estate->es_tupleTable);
resultRelInfo->ri_projectNewInfoValid = true;
}
/*
* Process BEFORE EACH STATEMENT triggers
*/
static void
fireBSTriggers(ModifyTableState *node)
{
ModifyTable *plan = (ModifyTable *) node->ps.plan;
ResultRelInfo *resultRelInfo = node->rootResultRelInfo;
switch (node->operation)
{
case CMD_INSERT:
ExecBSInsertTriggers(node->ps.state, resultRelInfo);
if (plan->onConflictAction == ONCONFLICT_UPDATE)
ExecBSUpdateTriggers(node->ps.state,
resultRelInfo);
break;
case CMD_UPDATE:
ExecBSUpdateTriggers(node->ps.state, resultRelInfo);
break;
case CMD_DELETE:
ExecBSDeleteTriggers(node->ps.state, resultRelInfo);
break;
case CMD_MERGE:
if (node->mt_merge_subcommands & MERGE_INSERT)
ExecBSInsertTriggers(node->ps.state, resultRelInfo);
if (node->mt_merge_subcommands & MERGE_UPDATE)
ExecBSUpdateTriggers(node->ps.state, resultRelInfo);
if (node->mt_merge_subcommands & MERGE_DELETE)
ExecBSDeleteTriggers(node->ps.state, resultRelInfo);
break;
default:
elog(ERROR, "unknown operation");
break;
}
}
/*
* Process AFTER EACH STATEMENT triggers
*/
static void
fireASTriggers(ModifyTableState *node)
{
ModifyTable *plan = (ModifyTable *) node->ps.plan;
ResultRelInfo *resultRelInfo = node->rootResultRelInfo;
switch (node->operation)
{
case CMD_INSERT:
if (plan->onConflictAction == ONCONFLICT_UPDATE)
ExecASUpdateTriggers(node->ps.state,
resultRelInfo,
node->mt_oc_transition_capture);
ExecASInsertTriggers(node->ps.state, resultRelInfo,
node->mt_transition_capture);
break;
case CMD_UPDATE:
ExecASUpdateTriggers(node->ps.state, resultRelInfo,
node->mt_transition_capture);
break;
case CMD_DELETE:
ExecASDeleteTriggers(node->ps.state, resultRelInfo,
node->mt_transition_capture);
break;
case CMD_MERGE:
if (node->mt_merge_subcommands & MERGE_DELETE)
ExecASDeleteTriggers(node->ps.state, resultRelInfo,
node->mt_transition_capture);
if (node->mt_merge_subcommands & MERGE_UPDATE)
ExecASUpdateTriggers(node->ps.state, resultRelInfo,
node->mt_transition_capture);
if (node->mt_merge_subcommands & MERGE_INSERT)
ExecASInsertTriggers(node->ps.state, resultRelInfo,
node->mt_transition_capture);
break;
default:
elog(ERROR, "unknown operation");
break;
}
}
/*
* Set up the state needed for collecting transition tuples for AFTER
* triggers.
*/
static void
ExecSetupTransitionCaptureState(ModifyTableState *mtstate, EState *estate)
{
ModifyTable *plan = (ModifyTable *) mtstate->ps.plan;
ResultRelInfo *targetRelInfo = mtstate->rootResultRelInfo;
/* Check for transition tables on the directly targeted relation. */
mtstate->mt_transition_capture =
MakeTransitionCaptureState(targetRelInfo->ri_TrigDesc,
RelationGetRelid(targetRelInfo->ri_RelationDesc),
mtstate->operation);
if (plan->operation == CMD_INSERT &&
plan->onConflictAction == ONCONFLICT_UPDATE)
mtstate->mt_oc_transition_capture =
MakeTransitionCaptureState(targetRelInfo->ri_TrigDesc,
RelationGetRelid(targetRelInfo->ri_RelationDesc),
CMD_UPDATE);
}
/*
* ExecPrepareTupleRouting --- prepare for routing one tuple
*
* Determine the partition in which the tuple in slot is to be inserted,
* and return its ResultRelInfo in *partRelInfo. The return value is
* a slot holding the tuple of the partition rowtype.
*
* This also sets the transition table information in mtstate based on the
* selected partition.
*/
static TupleTableSlot *
ExecPrepareTupleRouting(ModifyTableState *mtstate,
EState *estate,
PartitionTupleRouting *proute,
ResultRelInfo *targetRelInfo,
TupleTableSlot *slot,
ResultRelInfo **partRelInfo)
{
ResultRelInfo *partrel;
TupleConversionMap *map;
/*
* Lookup the target partition's ResultRelInfo. If ExecFindPartition does
* not find a valid partition for the tuple in 'slot' then an error is
* raised. An error may also be raised if the found partition is not a
* valid target for INSERTs. This is required since a partitioned table
* UPDATE to another partition becomes a DELETE+INSERT.
*/
partrel = ExecFindPartition(mtstate, targetRelInfo, proute, slot, estate);
/*
* If we're capturing transition tuples, we might need to convert from the
* partition rowtype to root partitioned table's rowtype. But if there
* are no BEFORE triggers on the partition that could change the tuple, we
* can just remember the original unconverted tuple to avoid a needless
* round trip conversion.
*/
if (mtstate->mt_transition_capture != NULL)
{
bool has_before_insert_row_trig;
has_before_insert_row_trig = (partrel->ri_TrigDesc &&
partrel->ri_TrigDesc->trig_insert_before_row);
mtstate->mt_transition_capture->tcs_original_insert_tuple =
!has_before_insert_row_trig ? slot : NULL;
}
/*
* Convert the tuple, if necessary.
*/
map = ExecGetRootToChildMap(partrel, estate);
if (map != NULL)
{
TupleTableSlot *new_slot = partrel->ri_PartitionTupleSlot;
slot = execute_attr_map_slot(map->attrMap, slot, new_slot);
}
*partRelInfo = partrel;
return slot;
}
/* ----------------------------------------------------------------
* ExecModifyTable
*
* Perform table modifications as required, and return RETURNING results
* if needed.
* ----------------------------------------------------------------
*/
static TupleTableSlot *
ExecModifyTable(PlanState *pstate)
{
ModifyTableState *node = castNode(ModifyTableState, pstate);
ModifyTableContext context;
EState *estate = node->ps.state;
CmdType operation = node->operation;
ResultRelInfo *resultRelInfo;
PlanState *subplanstate;
TupleTableSlot *slot;
TupleTableSlot *oldSlot;
ItemPointerData tuple_ctid;
HeapTupleData oldtupdata;
HeapTuple oldtuple;
ItemPointer tupleid;
bool tuplock;
CHECK_FOR_INTERRUPTS();
/*
* 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_epq_active != 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_lastResultIndex;
subplanstate = outerPlanState(node);
/* Set global context */
context.mtstate = node;
context.epqstate = &node->mt_epqstate;
context.estate = estate;
/*
* Fetch rows from subplan, 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);
/*
* Reset per-tuple memory context used for processing on conflict and
* returning clauses, to free any expression evaluation storage
* allocated in the previous cycle.
*/
if (pstate->ps_ExprContext)
ResetExprContext(pstate->ps_ExprContext);
/*
* If there is a pending MERGE ... WHEN NOT MATCHED [BY TARGET] action
* to execute, do so now --- see the comments in ExecMerge().
*/
if (node->mt_merge_pending_not_matched != NULL)
{
context.planSlot = node->mt_merge_pending_not_matched;
slot = ExecMergeNotMatched(&context, node->resultRelInfo,
node->canSetTag);
/* Clear the pending action */
node->mt_merge_pending_not_matched = NULL;
/*
* If we got a RETURNING result, return it to the caller. We'll
* continue the work on next call.
*/
if (slot)
return slot;
continue; /* continue with the next tuple */
}
/* Fetch the next row from subplan */
context.planSlot = ExecProcNode(subplanstate);
/* No more tuples to process? */
if (TupIsNull(context.planSlot))
break;
/*
* When there are multiple result relations, each tuple contains a
* junk column that gives the OID of the rel from which it came.
* Extract it and select the correct result relation.
*/
if (AttributeNumberIsValid(node->mt_resultOidAttno))
{
Datum datum;
bool isNull;
Oid resultoid;
datum = ExecGetJunkAttribute(context.planSlot, node->mt_resultOidAttno,
&isNull);
if (isNull)
{
/*
* For commands other than MERGE, any tuples having InvalidOid
* for tableoid are errors. For MERGE, we may need to handle
* them as WHEN NOT MATCHED clauses if any, so do that.
*
* Note that we use the node's toplevel resultRelInfo, not any
* specific partition's.
*/
if (operation == CMD_MERGE)
{
EvalPlanQualSetSlot(&node->mt_epqstate, context.planSlot);
slot = ExecMerge(&context, node->resultRelInfo,
NULL, NULL, node->canSetTag);
/*
* If we got a RETURNING result, return it to the caller.
* We'll continue the work on next call.
*/
if (slot)
return slot;
continue; /* continue with the next tuple */
}
elog(ERROR, "tableoid is NULL");
}
resultoid = DatumGetObjectId(datum);
/* If it's not the same as last time, we need to locate the rel */
if (resultoid != node->mt_lastResultOid)
resultRelInfo = ExecLookupResultRelByOid(node, resultoid,
false, true);
}
/*
* If resultRelInfo->ri_usesFdwDirectModify is true, all we need to do
* here is compute the RETURNING expressions.
*/
if (resultRelInfo->ri_usesFdwDirectModify)
{
Assert(resultRelInfo->ri_projectReturning);
/*
* A scan slot containing the data that was actually inserted,
* updated or deleted has already been made available to
* ExecProcessReturning by IterateDirectModify, so no need to
* provide it here.
*/
slot = ExecProcessReturning(resultRelInfo, NULL, context.planSlot);
return slot;
}
EvalPlanQualSetSlot(&node->mt_epqstate, context.planSlot);
slot = context.planSlot;
tupleid = NULL;
oldtuple = NULL;
/*
* For UPDATE/DELETE/MERGE, fetch the row identity info for the tuple
* to be updated/deleted/merged. For a heap relation, that's a TID;
* otherwise we may have a wholerow junk attr that carries the old
* tuple in toto. Keep this in step with the part of
* ExecInitModifyTable that sets up ri_RowIdAttNo.
*/
if (operation == CMD_UPDATE || operation == CMD_DELETE ||
operation == CMD_MERGE)
{
char relkind;
Datum datum;
bool isNull;
relkind = resultRelInfo->ri_RelationDesc->rd_rel->relkind;
if (relkind == RELKIND_RELATION ||
relkind == RELKIND_MATVIEW ||
relkind == RELKIND_PARTITIONED_TABLE)
{
/* ri_RowIdAttNo refers to a ctid attribute */
Assert(AttributeNumberIsValid(resultRelInfo->ri_RowIdAttNo));
datum = ExecGetJunkAttribute(slot,
resultRelInfo->ri_RowIdAttNo,
&isNull);
/*
* For commands other than MERGE, any tuples having a null row
* identifier are errors. For MERGE, we may need to handle
* them as WHEN NOT MATCHED clauses if any, so do that.
*
* Note that we use the node's toplevel resultRelInfo, not any
* specific partition's.
*/
if (isNull)
{
if (operation == CMD_MERGE)
{
EvalPlanQualSetSlot(&node->mt_epqstate, context.planSlot);
slot = ExecMerge(&context, node->resultRelInfo,
NULL, NULL, node->canSetTag);
/*
* If we got a RETURNING result, return it to the
* caller. We'll continue the work on next call.
*/
if (slot)
return slot;
continue; /* continue with the next tuple */
}
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. The old tuple serves one or both of two
* purposes: 1) it serves as the OLD tuple for row triggers, 2) it
* provides values for any unchanged columns for the NEW tuple of
* an UPDATE, because the subplan does not produce all the columns
* of the target table.
*
* Note that the wholerow attribute does not carry system columns,
* so 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(resultRelInfo->ri_RowIdAttNo))
{
datum = ExecGetJunkAttribute(slot,
resultRelInfo->ri_RowIdAttNo,
&isNull);
/*
* For commands other than MERGE, any tuples having a null row
* identifier are errors. For MERGE, we may need to handle
* them as WHEN NOT MATCHED clauses if any, so do that.
*
* Note that we use the node's toplevel resultRelInfo, not any
* specific partition's.
*/
if (isNull)
{
if (operation == CMD_MERGE)
{
EvalPlanQualSetSlot(&node->mt_epqstate, context.planSlot);
slot = ExecMerge(&context, node->resultRelInfo,
NULL, NULL, node->canSetTag);
/*
* If we got a RETURNING result, return it to the
* caller. We'll continue the work on next call.
*/
if (slot)
return slot;
continue; /* continue with the next tuple */
}
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
{
/* Only foreign tables are allowed to omit a row-ID attr */
Assert(relkind == RELKIND_FOREIGN_TABLE);
}
}
switch (operation)
{
case CMD_INSERT:
/* Initialize projection info if first time for this table */
if (unlikely(!resultRelInfo->ri_projectNewInfoValid))
ExecInitInsertProjection(node, resultRelInfo);
slot = ExecGetInsertNewTuple(resultRelInfo, context.planSlot);
slot = ExecInsert(&context, resultRelInfo, slot,
node->canSetTag, NULL, NULL);
break;
case CMD_UPDATE:
tuplock = false;
/* Initialize projection info if first time for this table */
if (unlikely(!resultRelInfo->ri_projectNewInfoValid))
ExecInitUpdateProjection(node, resultRelInfo);
/*
* Make the new tuple by combining plan's output tuple with
* the old tuple being updated.
*/
oldSlot = resultRelInfo->ri_oldTupleSlot;
if (oldtuple != NULL)
{
Assert(!resultRelInfo->ri_needLockTagTuple);
/* Use the wholerow junk attr as the old tuple. */
ExecForceStoreHeapTuple(oldtuple, oldSlot, false);
}
else
{
/* Fetch the most recent version of old tuple. */
Relation relation = resultRelInfo->ri_RelationDesc;
if (resultRelInfo->ri_needLockTagTuple)
{
LockTuple(relation, tupleid, InplaceUpdateTupleLock);
tuplock = true;
}
if (!table_tuple_fetch_row_version(relation, tupleid,
SnapshotAny,
oldSlot))
elog(ERROR, "failed to fetch tuple being updated");
}
slot = ExecGetUpdateNewTuple(resultRelInfo, context.planSlot,
oldSlot);
/* Now apply the update. */
slot = ExecUpdate(&context, resultRelInfo, tupleid, oldtuple,
slot, node->canSetTag);
if (tuplock)
UnlockTuple(resultRelInfo->ri_RelationDesc, tupleid,
InplaceUpdateTupleLock);
break;
case CMD_DELETE:
slot = ExecDelete(&context, resultRelInfo, tupleid, oldtuple,
true, false, node->canSetTag, NULL, NULL, NULL);
break;
case CMD_MERGE:
slot = ExecMerge(&context, resultRelInfo, tupleid, oldtuple,
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)
return slot;
}
/*
* Insert remaining tuples for batch insert.
*/
if (estate->es_insert_pending_result_relations != NIL)
ExecPendingInserts(estate);
/*
* We're done, but fire AFTER STATEMENT triggers before exiting.
*/
fireASTriggers(node);
node->mt_done = true;
return NULL;
}
/*
* ExecLookupResultRelByOid
* If the table with given OID is among the result relations to be
* updated by the given ModifyTable node, return its ResultRelInfo.
*
* If not found, return NULL if missing_ok, else raise error.
*
* If update_cache is true, then upon successful lookup, update the node's
* one-element cache. ONLY ExecModifyTable may pass true for this.
*/
ResultRelInfo *
ExecLookupResultRelByOid(ModifyTableState *node, Oid resultoid,
bool missing_ok, bool update_cache)
{
if (node->mt_resultOidHash)
{
/* Use the pre-built hash table to locate the rel */
MTTargetRelLookup *mtlookup;
mtlookup = (MTTargetRelLookup *)
hash_search(node->mt_resultOidHash, &resultoid, HASH_FIND, NULL);
if (mtlookup)
{
if (update_cache)
{
node->mt_lastResultOid = resultoid;
node->mt_lastResultIndex = mtlookup->relationIndex;
}
return node->resultRelInfo + mtlookup->relationIndex;
}
}
else
{
/* With few target rels, just search the ResultRelInfo array */
for (int ndx = 0; ndx < node->mt_nrels; ndx++)
{
ResultRelInfo *rInfo = node->resultRelInfo + ndx;
if (RelationGetRelid(rInfo->ri_RelationDesc) == resultoid)
{
if (update_cache)
{
node->mt_lastResultOid = resultoid;
node->mt_lastResultIndex = ndx;
}
return rInfo;
}
}
}
if (!missing_ok)
elog(ERROR, "incorrect result relation OID %u", resultoid);
return NULL;
}
/* ----------------------------------------------------------------
* ExecInitModifyTable
* ----------------------------------------------------------------
*/
ModifyTableState *
ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
{
ModifyTableState *mtstate;
Plan *subplan = outerPlan(node);
CmdType operation = node->operation;
int nrels = list_length(node->resultRelations);
ResultRelInfo *resultRelInfo;
List *arowmarks;
ListCell *l;
int i;
Relation rel;
/* 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.ExecProcNode = ExecModifyTable;
mtstate->operation = operation;
mtstate->canSetTag = node->canSetTag;
mtstate->mt_done = false;
mtstate->mt_nrels = nrels;
mtstate->resultRelInfo = (ResultRelInfo *)
palloc(nrels * sizeof(ResultRelInfo));
mtstate->mt_merge_pending_not_matched = NULL;
mtstate->mt_merge_inserted = 0;
mtstate->mt_merge_updated = 0;
mtstate->mt_merge_deleted = 0;
/*----------
* Resolve the target relation. This is the same as:
*
* - the relation for which we will fire FOR STATEMENT triggers,
* - the relation into whose tuple format all captured transition tuples
* must be converted, and
* - the root partitioned table used for tuple routing.
*
* If it's a partitioned or inherited table, the root partition or
* appendrel RTE doesn't appear elsewhere in the plan and its RT index is
* given explicitly in node->rootRelation. Otherwise, the target relation
* is the sole relation in the node->resultRelations list.
*----------
*/
if (node->rootRelation > 0)
{
mtstate->rootResultRelInfo = makeNode(ResultRelInfo);
ExecInitResultRelation(estate, mtstate->rootResultRelInfo,
node->rootRelation);
}
else
{
Assert(list_length(node->resultRelations) == 1);
mtstate->rootResultRelInfo = mtstate->resultRelInfo;
ExecInitResultRelation(estate, mtstate->resultRelInfo,
linitial_int(node->resultRelations));
}
/* set up epqstate with dummy subplan data for the moment */
EvalPlanQualInit(&mtstate->mt_epqstate, estate, NULL, NIL,
node->epqParam, node->resultRelations);
mtstate->fireBSTriggers = true;
/*
* Build state for collecting transition tuples. This requires having a
* valid trigger query context, so skip it in explain-only mode.
*/
if (!(eflags & EXEC_FLAG_EXPLAIN_ONLY))
ExecSetupTransitionCaptureState(mtstate, estate);
/*
* Open all the result relations and initialize the ResultRelInfo structs.
* (But root relation was initialized above, if it's part of the array.)
* We must do this before initializing the subplan, because direct-modify
* FDWs expect their ResultRelInfos to be available.
*/
resultRelInfo = mtstate->resultRelInfo;
i = 0;
foreach(l, node->resultRelations)
{
Index resultRelation = lfirst_int(l);
List *mergeActions = NIL;
if (node->mergeActionLists)
mergeActions = list_nth(node->mergeActionLists, i);
if (resultRelInfo != mtstate->rootResultRelInfo)
{
ExecInitResultRelation(estate, resultRelInfo, resultRelation);
/*
* For child result relations, store the root result relation
* pointer. We do so for the convenience of places that want to
* look at the query's original target relation but don't have the
* mtstate handy.
*/
resultRelInfo->ri_RootResultRelInfo = mtstate->rootResultRelInfo;
}
/* Initialize the usesFdwDirectModify flag */
resultRelInfo->ri_usesFdwDirectModify =
bms_is_member(i, node->fdwDirectModifyPlans);
/*
* Verify result relation is a valid target for the current operation
*/
CheckValidResultRel(resultRelInfo, operation, mergeActions);
resultRelInfo++;
i++;
}
/*
* Now we may initialize the subplan.
*/
outerPlanState(mtstate) = ExecInitNode(subplan, estate, eflags);
/*
* Do additional per-result-relation initialization.
*/
for (i = 0; i < nrels; i++)
{
resultRelInfo = &mtstate->resultRelInfo[i];
/* Let FDWs init themselves for foreign-table result rels */
if (!resultRelInfo->ri_usesFdwDirectModify &&
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);
}
/*
* For UPDATE/DELETE/MERGE, find the appropriate junk attr now, either
* a 'ctid' or 'wholerow' attribute depending on relkind. For foreign
* tables, the FDW might have created additional junk attr(s), but
* those are no concern of ours.
*/
if (operation == CMD_UPDATE || operation == CMD_DELETE ||
operation == CMD_MERGE)
{
char relkind;
relkind = resultRelInfo->ri_RelationDesc->rd_rel->relkind;
if (relkind == RELKIND_RELATION ||
relkind == RELKIND_MATVIEW ||
relkind == RELKIND_PARTITIONED_TABLE)
{
resultRelInfo->ri_RowIdAttNo =
ExecFindJunkAttributeInTlist(subplan->targetlist, "ctid");
if (!AttributeNumberIsValid(resultRelInfo->ri_RowIdAttNo))
elog(ERROR, "could not find junk ctid column");
}
else if (relkind == RELKIND_FOREIGN_TABLE)
{
/*
* We don't support MERGE with foreign tables for now. (It's
* problematic because the implementation uses CTID.)
*/
Assert(operation != CMD_MERGE);
/*
* When there is a row-level trigger, there should be a
* wholerow attribute. We also require it to be present in
* UPDATE and MERGE, so we can get the values of unchanged
* columns.
*/
resultRelInfo->ri_RowIdAttNo =
ExecFindJunkAttributeInTlist(subplan->targetlist,
"wholerow");
if ((mtstate->operation == CMD_UPDATE || mtstate->operation == CMD_MERGE) &&
!AttributeNumberIsValid(resultRelInfo->ri_RowIdAttNo))
elog(ERROR, "could not find junk wholerow column");
}
else
{
/* Other valid target relkinds must provide wholerow */
resultRelInfo->ri_RowIdAttNo =
ExecFindJunkAttributeInTlist(subplan->targetlist,
"wholerow");
if (!AttributeNumberIsValid(resultRelInfo->ri_RowIdAttNo))
elog(ERROR, "could not find junk wholerow column");
}
}
}
/*
* If this is an inherited update/delete/merge, there will be a junk
* attribute named "tableoid" present in the subplan's targetlist. It
* will be used to identify the result relation for a given tuple to be
* updated/deleted/merged.
*/
mtstate->mt_resultOidAttno =
ExecFindJunkAttributeInTlist(subplan->targetlist, "tableoid");
Assert(AttributeNumberIsValid(mtstate->mt_resultOidAttno) || nrels == 1);
mtstate->mt_lastResultOid = InvalidOid; /* force lookup at first tuple */
mtstate->mt_lastResultIndex = 0; /* must be zero if no such attr */
/* Get the root target relation */
rel = mtstate->rootResultRelInfo->ri_RelationDesc;
/*
* Build state for tuple routing if it's a partitioned INSERT. An UPDATE
* or MERGE might need this too, but only if it actually moves tuples
* between partitions; in that case setup is done by
* ExecCrossPartitionUpdate.
*/
if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE &&
operation == CMD_INSERT)
mtstate->mt_partition_tuple_routing =
ExecSetupPartitionTupleRouting(estate, rel);
/*
* Initialize any WITH CHECK OPTION constraints if needed.
*/
resultRelInfo = mtstate->resultRelInfo;
foreach(l, node->withCheckOptionLists)
{
List *wcoList = (List *) lfirst(l);
List *wcoExprs = NIL;
ListCell *ll;
foreach(ll, wcoList)
{
WithCheckOption *wco = (WithCheckOption *) lfirst(ll);
ExprState *wcoExpr = ExecInitQual((List *) wco->qual,
&mtstate->ps);
wcoExprs = lappend(wcoExprs, wcoExpr);
}
resultRelInfo->ri_WithCheckOptions = wcoList;
resultRelInfo->ri_WithCheckOptionExprs = wcoExprs;
resultRelInfo++;
}
/*
* 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.
*/
mtstate->ps.plan->targetlist = (List *) linitial(node->returningLists);
/* Set up a slot for the output of the RETURNING projection(s) */
ExecInitResultTupleSlotTL(&mtstate->ps, &TTSOpsVirtual);
slot = mtstate->ps.ps_ResultTupleSlot;
/* Need an econtext too */
if (mtstate->ps.ps_ExprContext == NULL)
ExecAssignExprContext(estate, &mtstate->ps);
econtext = mtstate->ps.ps_ExprContext;
/*
* Build a projection for each result rel.
*/
resultRelInfo = mtstate->resultRelInfo;
foreach(l, node->returningLists)
{
List *rlist = (List *) lfirst(l);
resultRelInfo->ri_returningList = rlist;
resultRelInfo->ri_projectReturning =
ExecBuildProjectionInfo(rlist, econtext, slot, &mtstate->ps,
resultRelInfo->ri_RelationDesc->rd_att);
resultRelInfo++;
}
}
else
{
/*
* We still must construct a dummy result tuple type, because InitPlan
* expects one (maybe should change that?).
*/
mtstate->ps.plan->targetlist = NIL;
ExecInitResultTypeTL(&mtstate->ps);
mtstate->ps.ps_ExprContext = NULL;
}
/* Set the list of arbiter indexes if needed for ON CONFLICT */
resultRelInfo = mtstate->resultRelInfo;
if (node->onConflictAction != ONCONFLICT_NONE)
{
/* insert may only have one relation, inheritance is not expanded */
Assert(nrels == 1);
resultRelInfo->ri_onConflictArbiterIndexes = node->arbiterIndexes;
}
/*
* If needed, Initialize target list, projection and qual for ON CONFLICT
* DO UPDATE.
*/
if (node->onConflictAction == ONCONFLICT_UPDATE)
{
OnConflictSetState *onconfl = makeNode(OnConflictSetState);
ExprContext *econtext;
TupleDesc relationDesc;
/* already exists if created by RETURNING processing above */
if (mtstate->ps.ps_ExprContext == NULL)
ExecAssignExprContext(estate, &mtstate->ps);
econtext = mtstate->ps.ps_ExprContext;
relationDesc = resultRelInfo->ri_RelationDesc->rd_att;
/* create state for DO UPDATE SET operation */
resultRelInfo->ri_onConflict = onconfl;
/* initialize slot for the existing tuple */
onconfl->oc_Existing =
table_slot_create(resultRelInfo->ri_RelationDesc,
&mtstate->ps.state->es_tupleTable);
/*
* Create the tuple slot for the UPDATE SET projection. We want a slot
* of the table's type here, because the slot will be used to insert
* into the table, and for RETURNING processing - which may access
* system attributes.
*/
onconfl->oc_ProjSlot =
table_slot_create(resultRelInfo->ri_RelationDesc,
&mtstate->ps.state->es_tupleTable);
/* build UPDATE SET projection state */
onconfl->oc_ProjInfo =
ExecBuildUpdateProjection(node->onConflictSet,
true,
node->onConflictCols,
relationDesc,
econtext,
onconfl->oc_ProjSlot,
&mtstate->ps);
/* initialize state to evaluate the WHERE clause, if any */
if (node->onConflictWhere)
{
ExprState *qualexpr;
qualexpr = ExecInitQual((List *) node->onConflictWhere,
&mtstate->ps);
onconfl->oc_WhereClause = 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, i.e., the
* EvalPlanQual mechanism needs to be told about them. This also goes for
* the source relations in a MERGE. Locate the relevant ExecRowMarks.
*/
arowmarks = NIL;
foreach(l, node->rowMarks)
{
PlanRowMark *rc = lfirst_node(PlanRowMark, l);
ExecRowMark *erm;
ExecAuxRowMark *aerm;
/* ignore "parent" rowmarks; they are irrelevant at runtime */
if (rc->isParent)
continue;
/* Find ExecRowMark and build ExecAuxRowMark */
erm = ExecFindRowMark(estate, rc->rti, false);
aerm = ExecBuildAuxRowMark(erm, subplan->targetlist);
arowmarks = lappend(arowmarks, aerm);
}
/* For a MERGE command, initialize its state */
if (mtstate->operation == CMD_MERGE)
ExecInitMerge(mtstate, estate);
EvalPlanQualSetPlan(&mtstate->mt_epqstate, subplan, arowmarks);
/*
* If there are a lot of result relations, use a hash table to speed the
* lookups. If there are not a lot, a simple linear search is faster.
*
* It's not clear where the threshold is, but try 64 for starters. In a
* debugging build, use a small threshold so that we get some test
* coverage of both code paths.
*/
#ifdef USE_ASSERT_CHECKING
#define MT_NRELS_HASH 4
#else
#define MT_NRELS_HASH 64
#endif
if (nrels >= MT_NRELS_HASH)
{
HASHCTL hash_ctl;
hash_ctl.keysize = sizeof(Oid);
hash_ctl.entrysize = sizeof(MTTargetRelLookup);
hash_ctl.hcxt = CurrentMemoryContext;
mtstate->mt_resultOidHash =
hash_create("ModifyTable target hash",
nrels, &hash_ctl,
HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
for (i = 0; i < nrels; i++)
{
Oid hashkey;
MTTargetRelLookup *mtlookup;
bool found;
resultRelInfo = &mtstate->resultRelInfo[i];
hashkey = RelationGetRelid(resultRelInfo->ri_RelationDesc);
mtlookup = (MTTargetRelLookup *)
hash_search(mtstate->mt_resultOidHash, &hashkey,
HASH_ENTER, &found);
Assert(!found);
mtlookup->relationIndex = i;
}
}
else
mtstate->mt_resultOidHash = NULL;
/*
* Determine if the FDW supports batch insert and determine the batch size
* (a FDW may support batching, but it may be disabled for the
* server/table).
*
* We only do this for INSERT, so that for UPDATE/DELETE the batch size
* remains set to 0.
*/
if (operation == CMD_INSERT)
{
/* insert may only have one relation, inheritance is not expanded */
Assert(nrels == 1);
resultRelInfo = mtstate->resultRelInfo;
if (!resultRelInfo->ri_usesFdwDirectModify &&
resultRelInfo->ri_FdwRoutine != NULL &&
resultRelInfo->ri_FdwRoutine->GetForeignModifyBatchSize &&
resultRelInfo->ri_FdwRoutine->ExecForeignBatchInsert)
{
resultRelInfo->ri_BatchSize =
resultRelInfo->ri_FdwRoutine->GetForeignModifyBatchSize(resultRelInfo);
Assert(resultRelInfo->ri_BatchSize >= 1);
}
else
resultRelInfo->ri_BatchSize = 1;
}
/*
* 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_nrels; i++)
{
int j;
ResultRelInfo *resultRelInfo = node->resultRelInfo + i;
if (!resultRelInfo->ri_usesFdwDirectModify &&
resultRelInfo->ri_FdwRoutine != NULL &&
resultRelInfo->ri_FdwRoutine->EndForeignModify != NULL)
resultRelInfo->ri_FdwRoutine->EndForeignModify(node->ps.state,
resultRelInfo);
/*
* Cleanup the initialized batch slots. This only matters for FDWs
* with batching, but the other cases will have ri_NumSlotsInitialized
* == 0.
*/
for (j = 0; j < resultRelInfo->ri_NumSlotsInitialized; j++)
{
ExecDropSingleTupleTableSlot(resultRelInfo->ri_Slots[j]);
ExecDropSingleTupleTableSlot(resultRelInfo->ri_PlanSlots[j]);
}
}
/*
* Close all the partitioned tables, leaf partitions, and their indices
* and release the slot used for tuple routing, if set.
*/
if (node->mt_partition_tuple_routing)
{
ExecCleanupTupleRouting(node, node->mt_partition_tuple_routing);
if (node->mt_root_tuple_slot)
ExecDropSingleTupleTableSlot(node->mt_root_tuple_slot);
}
/*
* Terminate EPQ execution if active
*/
EvalPlanQualEnd(&node->mt_epqstate);
/*
* shut down subplan
*/
ExecEndNode(outerPlanState(node));
}
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");
}