Header And Logo
|
#include "postgres.h"#include "access/htup_details.h"#include "access/xact.h"#include "executor/executor.h"#include "executor/nodeLockRows.h"#include "storage/bufmgr.h"#include "utils/rel.h"#include "utils/tqual.h"
Go to the source code of this file.
Functions | |
| TupleTableSlot * | ExecLockRows (LockRowsState *node) |
| LockRowsState * | ExecInitLockRows (LockRows *node, EState *estate, int eflags) |
| void | ExecEndLockRows (LockRowsState *node) |
| void | ExecReScanLockRows (LockRowsState *node) |
| void ExecEndLockRows | ( | LockRowsState * | node | ) |
Definition at line 368 of file nodeLockRows.c.
References EvalPlanQualEnd(), ExecEndNode(), LockRowsState::lr_epqstate, and outerPlanState.
Referenced by ExecEndNode().
{
EvalPlanQualEnd(&node->lr_epqstate);
ExecEndNode(outerPlanState(node));
}
| LockRowsState* ExecInitLockRows | ( | LockRows * | node, | |
| EState * | estate, | |||
| int | eflags | |||
| ) |
Definition at line 278 of file nodeLockRows.c.
References Assert, LockRows::epqParam, EvalPlanQualInit(), EXEC_FLAG_MARK, ExecAssignResultTypeFromTL(), ExecBuildAuxRowMark(), ExecFindRowMark(), ExecInitNode(), ExecInitResultTupleSlot(), IsA, PlanRowMark::isParent, lappend(), lfirst, LockRowsState::lr_arowMarks, LockRowsState::lr_epqstate, makeNode, ExecRowMark::markType, outerPlan, outerPlanState, PlanState::plan, LockRowsState::ps, PlanState::ps_ProjInfo, RowMarkRequiresRowShareLock, LockRows::rowMarks, PlanRowMark::rti, PlanState::state, and Plan::targetlist.
Referenced by ExecInitNode().
{
LockRowsState *lrstate;
Plan *outerPlan = outerPlan(node);
List *epq_arowmarks;
ListCell *lc;
/* check for unsupported flags */
Assert(!(eflags & EXEC_FLAG_MARK));
/*
* create state structure
*/
lrstate = makeNode(LockRowsState);
lrstate->ps.plan = (Plan *) node;
lrstate->ps.state = estate;
/*
* Miscellaneous initialization
*
* LockRows nodes never call ExecQual or ExecProject.
*/
/*
* Tuple table initialization (XXX not actually used...)
*/
ExecInitResultTupleSlot(estate, &lrstate->ps);
/*
* then initialize outer plan
*/
outerPlanState(lrstate) = ExecInitNode(outerPlan, estate, eflags);
/*
* LockRows nodes do no projections, so initialize projection info for
* this node appropriately
*/
ExecAssignResultTypeFromTL(&lrstate->ps);
lrstate->ps.ps_ProjInfo = NULL;
/*
* Locate the ExecRowMark(s) that this node is responsible for, and
* construct ExecAuxRowMarks for them. (InitPlan should already have
* built the global list of ExecRowMarks.)
*/
lrstate->lr_arowMarks = NIL;
epq_arowmarks = NIL;
foreach(lc, node->rowMarks)
{
PlanRowMark *rc = (PlanRowMark *) lfirst(lc);
ExecRowMark *erm;
ExecAuxRowMark *aerm;
Assert(IsA(rc, PlanRowMark));
/* ignore "parent" rowmarks; they are irrelevant at runtime */
if (rc->isParent)
continue;
/* find ExecRowMark and build ExecAuxRowMark */
erm = ExecFindRowMark(estate, rc->rti);
aerm = ExecBuildAuxRowMark(erm, outerPlan->targetlist);
/*
* Only locking rowmarks go into our own list. Non-locking marks are
* passed off to the EvalPlanQual machinery. This is because we don't
* want to bother fetching non-locked rows unless we actually have to
* do an EPQ recheck.
*/
if (RowMarkRequiresRowShareLock(erm->markType))
lrstate->lr_arowMarks = lappend(lrstate->lr_arowMarks, aerm);
else
epq_arowmarks = lappend(epq_arowmarks, aerm);
}
/* Now we have the info needed to set up EPQ state */
EvalPlanQualInit(&lrstate->lr_epqstate, estate,
outerPlan, epq_arowmarks, node->epqParam);
return lrstate;
}
| TupleTableSlot* ExecLockRows | ( | LockRowsState * | node | ) |
Definition at line 38 of file nodeLockRows.c.
References Assert, HeapUpdateFailureData::ctid, ExecAuxRowMark::ctidAttNo, ExecRowMark::curCtid, DatumGetObjectId, DatumGetPointer, elog, ereport, errcode(), errmsg(), ERROR, EState::es_output_cid, EPQState::estate, EvalPlanQualBegin(), EvalPlanQualFetch(), EvalPlanQualFetchRowMarks(), EvalPlanQualGetTuple(), EvalPlanQualNext(), EvalPlanQualSetSlot, EvalPlanQualSetTuple(), ExecGetJunkAttribute(), ExecProcNode(), heap_copytuple(), heap_fetch(), heap_lock_tuple(), HeapTupleMayBeUpdated, HeapTupleSelfUpdated, HeapTupleUpdated, IsolationUsesXactSnapshot, ItemPointerEquals(), ItemPointerIsValid, ItemPointerSetInvalid, lfirst, lnext, LockRowsState::lr_arowMarks, LockRowsState::lr_epqstate, ExecRowMark::markType, ExecRowMark::noWait, NULL, outerPlanState, ExecRowMark::prti, LockRowsState::ps, ExecRowMark::relation, RelationGetRelid, ReleaseBuffer(), ROW_MARK_EXCLUSIVE, ROW_MARK_KEYSHARE, ROW_MARK_NOKEYEXCLUSIVE, ROW_MARK_SHARE, ExecAuxRowMark::rowmark, ExecRowMark::rti, SnapshotAny, PlanState::state, HeapTupleData::t_self, ExecAuxRowMark::toidAttNo, TupIsNull, and HeapUpdateFailureData::xmax.
Referenced by ExecProcNode().
{
TupleTableSlot *slot;
EState *estate;
PlanState *outerPlan;
bool epq_started;
ListCell *lc;
/*
* get information from the node
*/
estate = node->ps.state;
outerPlan = outerPlanState(node);
/*
* Get next tuple from subplan, if any.
*/
lnext:
slot = ExecProcNode(outerPlan);
if (TupIsNull(slot))
return NULL;
/*
* Attempt to lock the source tuple(s). (Note we only have locking
* rowmarks in lr_arowMarks.)
*/
epq_started = false;
foreach(lc, node->lr_arowMarks)
{
ExecAuxRowMark *aerm = (ExecAuxRowMark *) lfirst(lc);
ExecRowMark *erm = aerm->rowmark;
Datum datum;
bool isNull;
HeapTupleData tuple;
Buffer buffer;
HeapUpdateFailureData hufd;
LockTupleMode lockmode;
HTSU_Result test;
HeapTuple copyTuple;
/* clear any leftover test tuple for this rel */
if (node->lr_epqstate.estate != NULL)
EvalPlanQualSetTuple(&node->lr_epqstate, erm->rti, NULL);
/* if child rel, must check whether it produced this row */
if (erm->rti != erm->prti)
{
Oid tableoid;
datum = ExecGetJunkAttribute(slot,
aerm->toidAttNo,
&isNull);
/* shouldn't ever get a null result... */
if (isNull)
elog(ERROR, "tableoid is NULL");
tableoid = DatumGetObjectId(datum);
if (tableoid != RelationGetRelid(erm->relation))
{
/* this child is inactive right now */
ItemPointerSetInvalid(&(erm->curCtid));
continue;
}
}
/* fetch the tuple's ctid */
datum = ExecGetJunkAttribute(slot,
aerm->ctidAttNo,
&isNull);
/* shouldn't ever get a null result... */
if (isNull)
elog(ERROR, "ctid is NULL");
tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
/* okay, try to lock the tuple */
switch (erm->markType)
{
case ROW_MARK_EXCLUSIVE:
lockmode = LockTupleExclusive;
break;
case ROW_MARK_NOKEYEXCLUSIVE:
lockmode = LockTupleNoKeyExclusive;
break;
case ROW_MARK_SHARE:
lockmode = LockTupleShare;
break;
case ROW_MARK_KEYSHARE:
lockmode = LockTupleKeyShare;
break;
default:
elog(ERROR, "unsupported rowmark type");
lockmode = LockTupleNoKeyExclusive; /* keep compiler quiet */
break;
}
test = heap_lock_tuple(erm->relation, &tuple,
estate->es_output_cid,
lockmode, erm->noWait, true,
&buffer, &hufd);
ReleaseBuffer(buffer);
switch (test)
{
case HeapTupleSelfUpdated:
/*
* The target tuple was already updated or deleted by the
* current command, or by a later command in the current
* transaction. We *must* ignore the tuple in the former
* case, so as to avoid the "Halloween problem" of repeated
* update attempts. In the latter case it might be sensible
* to fetch the updated tuple instead, but doing so would
* require changing heap_lock_tuple as well as heap_update and
* heap_delete to not complain about updating "invisible"
* tuples, which seems pretty scary. So for now, treat the
* tuple as deleted and do not process.
*/
goto lnext;
case HeapTupleMayBeUpdated:
/* got the lock successfully */
break;
case HeapTupleUpdated:
if (IsolationUsesXactSnapshot())
ereport(ERROR,
(errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
errmsg("could not serialize access due to concurrent update")));
if (ItemPointerEquals(&hufd.ctid, &tuple.t_self))
{
/* Tuple was deleted, so don't return it */
goto lnext;
}
/* updated, so fetch and lock the updated version */
copyTuple = EvalPlanQualFetch(estate, erm->relation, lockmode,
&hufd.ctid, hufd.xmax);
if (copyTuple == NULL)
{
/* Tuple was deleted, so don't return it */
goto lnext;
}
/* remember the actually locked tuple's TID */
tuple.t_self = copyTuple->t_self;
/*
* Need to run a recheck subquery. Initialize EPQ state if we
* didn't do so already.
*/
if (!epq_started)
{
EvalPlanQualBegin(&node->lr_epqstate, estate);
epq_started = true;
}
/* Store target tuple for relation's scan node */
EvalPlanQualSetTuple(&node->lr_epqstate, erm->rti, copyTuple);
/* Continue loop until we have all target tuples */
break;
default:
elog(ERROR, "unrecognized heap_lock_tuple status: %u",
test);
}
/* Remember locked tuple's TID for WHERE CURRENT OF */
erm->curCtid = tuple.t_self;
}
/*
* If we need to do EvalPlanQual testing, do so.
*/
if (epq_started)
{
/*
* First, fetch a copy of any rows that were successfully locked
* without any update having occurred. (We do this in a separate pass
* so as to avoid overhead in the common case where there are no
* concurrent updates.)
*/
foreach(lc, node->lr_arowMarks)
{
ExecAuxRowMark *aerm = (ExecAuxRowMark *) lfirst(lc);
ExecRowMark *erm = aerm->rowmark;
HeapTupleData tuple;
Buffer buffer;
/* ignore non-active child tables */
if (!ItemPointerIsValid(&(erm->curCtid)))
{
Assert(erm->rti != erm->prti); /* check it's child table */
continue;
}
if (EvalPlanQualGetTuple(&node->lr_epqstate, erm->rti) != NULL)
continue; /* it was updated and fetched above */
/* okay, fetch the tuple */
tuple.t_self = erm->curCtid;
if (!heap_fetch(erm->relation, SnapshotAny, &tuple, &buffer,
false, NULL))
elog(ERROR, "failed to fetch tuple for EvalPlanQual recheck");
/* successful, copy and store tuple */
EvalPlanQualSetTuple(&node->lr_epqstate, erm->rti,
heap_copytuple(&tuple));
ReleaseBuffer(buffer);
}
/*
* Now fetch any non-locked source rows --- the EPQ logic knows how to
* do that.
*/
EvalPlanQualSetSlot(&node->lr_epqstate, slot);
EvalPlanQualFetchRowMarks(&node->lr_epqstate);
/*
* And finally we can re-evaluate the tuple.
*/
slot = EvalPlanQualNext(&node->lr_epqstate);
if (TupIsNull(slot))
{
/* Updated tuple fails qual, so ignore it and go on */
goto lnext;
}
}
/* Got all locks, so return the current tuple */
return slot;
}
| void ExecReScanLockRows | ( | LockRowsState * | node | ) |
Definition at line 376 of file nodeLockRows.c.
References PlanState::chgParam, ExecReScan(), PlanState::lefttree, NULL, and LockRowsState::ps.
Referenced by ExecReScan().
1.7.1