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apache / hawq / 91c45cab0e5844abfe0f398f2378637f4028fe45 / . / src / backend / executor / nodeSubplan.c
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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*-------------------------------------------------------------------------
*
* nodeSubplan.c
* routines to support subselects
*
* Portions Copyright (c) 2005-2010, Greenplum inc
* Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/nodeSubplan.c,v 1.80.2.2 2007/02/02 00:07:28 tgl Exp $
*
*-------------------------------------------------------------------------
*/
/*
* INTERFACE ROUTINES
* ExecSubPlan - process a subselect
* ExecInitSubPlan - initialize a subselect
* ExecEndSubPlan - shut down a subselect
*/
#include "postgres.h"
#include <math.h>
#include "access/heapam.h"
#include "executor/executor.h"
#include "executor/nodeSubplan.h"
#include "cdb/cdbexplain.h" /* cdbexplain_recvSubplanStats */
#include "cdb/cdbvars.h"
#include "cdb/cdbsrlz.h"
#include "cdb/cdbdisp.h"
#include "cdb/ml_ipc.h"
#include "lib/stringinfo.h"
#include "nodes/makefuncs.h"
#include "optimizer/clauses.h"
#include "utils/array.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "cdb/dispatcher.h"
#include <math.h> /* ceil() */
static Datum ExecHashSubPlan(SubPlanState *node,
ExprContext *econtext,
bool *isNull);
static Datum ExecScanSubPlan(SubPlanState *node,
ExprContext *econtext,
bool *isNull);
static void buildSubPlanHash(SubPlanState *node, ExprContext * econtext);
static bool findPartialMatch(TupleHashTable hashtable, TupleTableSlot *slot);
static bool slotAllNulls(TupleTableSlot *slot);
static bool slotNoNulls(TupleTableSlot *slot);
/* ----------------------------------------------------------------
* ExecSubPlan
* ----------------------------------------------------------------
*/
Datum
ExecSubPlan(SubPlanState *node,
ExprContext *econtext,
bool *isNull,
ExprDoneCond *isDone)
{
SubPlan *subplan = (SubPlan *) node->xprstate.expr;
/* Set default values for result flags: non-null, not a set result */
*isNull = false;
if (isDone)
*isDone = ExprSingleResult;
insist_log(subplan->setParam == NIL, "cannot set parent parameters from subquery");
if (subplan->useHashTable)
return ExecHashSubPlan(node, econtext, isNull);
else
return ExecScanSubPlan(node, econtext, isNull);
}
/*
* ExecHashSubPlan: store subselect result in an in-memory hash table
*/
static Datum
ExecHashSubPlan(SubPlanState *node,
ExprContext *econtext,
bool *isNull)
{
SubPlan *subplan = (SubPlan *) node->xprstate.expr;
PlanState *planstate = node->planstate;
TupleTableSlot *slot;
/* Shouldn't have any direct correlation Vars */
if (subplan->parParam != NIL || node->args != NIL)
elog(ERROR, "hashed subplan with direct correlation not supported");
/*
* If first time through or we need to rescan the subplan, build the hash
* table.
*/
if (node->hashtable == NULL || planstate->chgParam != NULL)
buildSubPlanHash(node, econtext);
/*
* The result for an empty subplan is always FALSE; no need to evaluate
* lefthand side.
*/
*isNull = false;
if (!node->havehashrows && !node->havenullrows)
return BoolGetDatum(false);
/*
* Evaluate lefthand expressions and form a projection tuple. First we
* have to set the econtext to use (hack alert!).
*/
node->projLeft->pi_exprContext = econtext;
slot = ExecProject(node->projLeft, NULL);
/*
* Note: because we are typically called in a per-tuple context, we have
* to explicitly clear the projected tuple before returning. Otherwise,
* we'll have a double-free situation: the per-tuple context will probably
* be reset before we're called again, and then the tuple slot will think
* it still needs to free the tuple.
*/
/*
* If the LHS is all non-null, probe for an exact match in the main hash
* table. If we find one, the result is TRUE. Otherwise, scan the
* partly-null table to see if there are any rows that aren't provably
* unequal to the LHS; if so, the result is UNKNOWN. (We skip that part
* if we don't care about UNKNOWN.) Otherwise, the result is FALSE.
*
* Note: the reason we can avoid a full scan of the main hash table is
* that the combining operators are assumed never to yield NULL when both
* inputs are non-null. If they were to do so, we might need to produce
* UNKNOWN instead of FALSE because of an UNKNOWN result in comparing the
* LHS to some main-table entry --- which is a comparison we will not even
* make, unless there's a chance match of hash keys.
*/
if (slotNoNulls(slot))
{
if (node->havehashrows &&
LookupTupleHashEntry(node->hashtable, slot, NULL) != NULL)
{
ExecClearTuple(slot);
return BoolGetDatum(true);
}
if (node->havenullrows &&
findPartialMatch(node->hashnulls, slot))
{
ExecClearTuple(slot);
*isNull = true;
return BoolGetDatum(false);
}
ExecClearTuple(slot);
return BoolGetDatum(false);
}
/*
* When the LHS is partly or wholly NULL, we can never return TRUE. If we
* don't care about UNKNOWN, just return FALSE. Otherwise, if the LHS is
* wholly NULL, immediately return UNKNOWN. (Since the combining
* operators are strict, the result could only be FALSE if the sub-select
* were empty, but we already handled that case.) Otherwise, we must scan
* both the main and partly-null tables to see if there are any rows that
* aren't provably unequal to the LHS; if so, the result is UNKNOWN.
* Otherwise, the result is FALSE.
*/
if (node->hashnulls == NULL)
{
ExecClearTuple(slot);
return BoolGetDatum(false);
}
if (slotAllNulls(slot))
{
ExecClearTuple(slot);
*isNull = true;
return BoolGetDatum(false);
}
/* Scan partly-null table first, since more likely to get a match */
if (node->havenullrows &&
findPartialMatch(node->hashnulls, slot))
{
ExecClearTuple(slot);
*isNull = true;
return BoolGetDatum(false);
}
if (node->havehashrows &&
findPartialMatch(node->hashtable, slot))
{
ExecClearTuple(slot);
*isNull = true;
return BoolGetDatum(false);
}
ExecClearTuple(slot);
return BoolGetDatum(false);
}
/*
* ExecScanSubPlan: default case where we have to rescan subplan each time
*/
static Datum
ExecScanSubPlan(SubPlanState *node,
ExprContext *econtext,
bool *isNull)
{
SubPlan *subplan = (SubPlan *) node->xprstate.expr;
PlanState *planstate = node->planstate;
SubLinkType subLinkType = subplan->subLinkType;
MemoryContext oldcontext;
TupleTableSlot *slot;
Datum result;
bool found = false; /* TRUE if got at least one subplan tuple */
ListCell *pvar;
ListCell *l;
ArrayBuildState *astate = NULL;
/*
* We are probably in a short-lived expression-evaluation context. Switch
* to the per-query context for manipulating the child plan's chgParam,
* calling ExecProcNode on it, etc.
*/
oldcontext = MemoryContextSwitchTo(node->sub_estate->es_query_cxt);
/*
* Set Params of this plan from parent plan correlation values. (Any
* calculation we have to do is done in the parent econtext, since the
* Param values don't need to have per-query lifetime.)
*/
Assert(list_length(subplan->parParam) == list_length(node->args));
forboth(l, subplan->parParam, pvar, node->args)
{
int paramid = lfirst_int(l);
ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
prm->value = ExecEvalExprSwitchContext((ExprState *) lfirst(pvar),
econtext,
&(prm->isnull),
NULL);
planstate->chgParam = bms_add_member(planstate->chgParam, paramid);
}
/*
* Now that we've set up its parameters, we can reset the subplan.
*/
ExecReScan(planstate, NULL);
/*
* For all sublink types except EXPR_SUBLINK and ARRAY_SUBLINK, the result
* is boolean as are the results of the combining operators. We combine
* results across tuples (if the subplan produces more than one) using OR
* semantics for ANY_SUBLINK or AND semantics for ALL_SUBLINK.
* (ROWCOMPARE_SUBLINK doesn't allow multiple tuples from the subplan.)
* NULL results from the combining operators are handled according to the
* usual SQL semantics for OR and AND. The result for no input tuples is
* FALSE for ANY_SUBLINK, TRUE for {ALL_SUBLINK, NOT_EXISTS_SUBLINK}, NULL for
* ROWCOMPARE_SUBLINK.
*
* For EXPR_SUBLINK we require the subplan to produce no more than one
* tuple, else an error is raised. If zero tuples are produced, we return
* NULL. Assuming we get a tuple, we just use its first column (there can
* be only one non-junk column in this case).
*
* For ARRAY_SUBLINK we allow the subplan to produce any number of tuples,
* and form an array of the first column's values. Note in particular
* that we produce a zero-element array if no tuples are produced (this is
* a change from pre-8.3 behavior of returning NULL).
*/
result = BoolGetDatum(subLinkType == ALL_SUBLINK || subLinkType == NOT_EXISTS_SUBLINK);
*isNull = false;
for (slot = ExecProcNode(planstate);
!TupIsNull(slot);
slot = ExecProcNode(planstate))
{
Datum rowresult;
bool rownull;
int col;
ListCell *plst;
if (subLinkType == EXISTS_SUBLINK || subLinkType == NOT_EXISTS_SUBLINK)
{
found = true;
bool val = true;
if (subLinkType == NOT_EXISTS_SUBLINK)
{
val = false;
}
result = BoolGetDatum(val);
break;
}
if (subLinkType == EXPR_SUBLINK)
{
/* cannot allow multiple input tuples for EXPR sublink */
if (found)
ereport(ERROR,
(errcode(ERRCODE_CARDINALITY_VIOLATION),
errmsg("more than one row returned by a subquery used as an expression")));
found = true;
/*
* We need to copy the subplan's tuple in case the result is of
* pass-by-ref type --- our return value will point into this
* copied tuple! Can't use the subplan's instance of the tuple
* since it won't still be valid after next ExecProcNode() call.
* node->curTuple keeps track of the copied tuple for eventual
* freeing.
*/
MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
if (node->curTuple)
pfree(node->curTuple);
node->curTuple = ExecCopySlotMemTuple(slot);
MemoryContextSwitchTo(node->sub_estate->es_query_cxt);
result = memtuple_getattr(node->curTuple, slot->tts_mt_bind, 1, isNull);
/* keep scanning subplan to make sure there's only one tuple */
continue;
}
if (subLinkType == ARRAY_SUBLINK)
{
Datum dvalue;
bool disnull;
found = true;
/* stash away current value */
Assert(subplan->firstColType == slot->tts_tupleDescriptor->attrs[0]->atttypid);
dvalue = slot_getattr(slot, 1, &disnull);
astate = accumArrayResult(astate, dvalue, disnull,
subplan->firstColType, oldcontext);
/* keep scanning subplan to collect all values */
continue;
}
/* cannot allow multiple input tuples for ROWCOMPARE sublink either */
if (subLinkType == ROWCOMPARE_SUBLINK && found)
ereport(ERROR,
(errcode(ERRCODE_CARDINALITY_VIOLATION),
errmsg("more than one row returned by a subquery used as an expression")));
found = true;
/*
* For ALL, ANY, and ROWCOMPARE sublinks, load up the Params
* representing the columns of the sub-select, and then evaluate the
* combining expression.
*/
col = 1;
foreach(plst, subplan->paramIds)
{
int paramid = lfirst_int(plst);
ParamExecData *prmdata;
prmdata = &(econtext->ecxt_param_exec_vals[paramid]);
Assert(prmdata->execPlan == NULL);
prmdata->value = slot_getattr(slot, col, &(prmdata->isnull));
col++;
}
rowresult = ExecEvalExprSwitchContext(node->testexpr, econtext,
&rownull, NULL);
if (subLinkType == ANY_SUBLINK)
{
/* combine across rows per OR semantics */
if (rownull)
*isNull = true;
else if (DatumGetBool(rowresult))
{
result = BoolGetDatum(true);
*isNull = false;
break; /* needn't look at any more rows */
}
}
else if (subLinkType == ALL_SUBLINK)
{
/* combine across rows per AND semantics */
if (rownull)
*isNull = true;
else if (!DatumGetBool(rowresult))
{
result = BoolGetDatum(false);
*isNull = false;
break; /* needn't look at any more rows */
}
}
else
{
/* must be ROWCOMPARE_SUBLINK */
result = rowresult;
*isNull = rownull;
}
}
if (!found)
{
/*
* deal with empty subplan result. result/isNull were previously
* initialized correctly for all sublink types except EXPR, ARRAY, and
* ROWCOMPARE; for those, return NULL.
*/
if (subLinkType == EXPR_SUBLINK ||
subLinkType == ARRAY_SUBLINK ||
subLinkType == ROWCOMPARE_SUBLINK)
{
result = (Datum) 0;
*isNull = true;
}
}
else if (subLinkType == ARRAY_SUBLINK)
{
Assert(astate != NULL);
/* We return the result in the caller's context */
result = makeArrayResult(astate, oldcontext);
}
MemoryContextSwitchTo(oldcontext);
return result;
}
/*
* buildSubPlanHash: load hash table by scanning subplan output.
*/
static void
buildSubPlanHash(SubPlanState *node, ExprContext *econtext)
{
SubPlan *subplan = (SubPlan *) node->xprstate.expr;
PlanState *planstate = node->planstate;
int ncols = list_length(subplan->paramIds);
ExprContext *innerecontext = node->innerecontext;
MemoryContext oldcontext;
int nbuckets;
TupleTableSlot *slot;
Assert(subplan->subLinkType == ANY_SUBLINK);
/*
* If we already had any hash tables, destroy 'em; then create empty hash
* table(s).
*
* If we need to distinguish accurately between FALSE and UNKNOWN (i.e.,
* NULL) results of the IN operation, then we have to store subplan output
* rows that are partly or wholly NULL. We store such rows in a separate
* hash table that we expect will be much smaller than the main table. (We
* can use hashing to eliminate partly-null rows that are not distinct. We
* keep them separate to minimize the cost of the inevitable full-table
* searches; see findPartialMatch.)
*
* If it's not necessary to distinguish FALSE and UNKNOWN, then we don't
* need to store subplan output rows that contain NULL.
*/
ExecEagerFreeSubPlan(node);
nbuckets = (int) ceil(planstate->plan->plan_rows);
if (nbuckets < 1)
nbuckets = 1;
node->hashtable = BuildTupleHashTable(ncols,
node->keyColIdx,
node->eqfunctions,
node->hashfunctions,
nbuckets,
sizeof(TupleHashEntryData),
node->hashtablecxt,
node->hashtempcxt);
if (!subplan->unknownEqFalse)
{
if (ncols == 1)
nbuckets = 1; /* there can only be one entry */
else
{
nbuckets /= 16;
if (nbuckets < 1)
nbuckets = 1;
}
node->hashnulls = BuildTupleHashTable(ncols,
node->keyColIdx,
node->eqfunctions,
node->hashfunctions,
nbuckets,
sizeof(TupleHashEntryData),
node->hashtablecxt,
node->hashtempcxt);
}
/*
* We are probably in a short-lived expression-evaluation context. Switch
* to the child plan's per-query context for calling ExecProcNode.
*/
oldcontext = MemoryContextSwitchTo(node->sub_estate->es_query_cxt);
/*
* Reset subplan to start.
*/
ExecReScan(planstate, NULL);
/*
* Scan the subplan and load the hash table(s). Note that when there are
* duplicate rows coming out of the sub-select, only one copy is stored.
*/
for (slot = ExecProcNode(planstate);
!TupIsNull(slot);
slot = ExecProcNode(planstate))
{
int col = 1;
ListCell *plst;
bool isnew;
/*
* Load up the Params representing the raw sub-select outputs, then
* form the projection tuple to store in the hashtable.
*/
foreach(plst, subplan->paramIds)
{
int paramid = lfirst_int(plst);
ParamExecData *prmdata;
prmdata = &(innerecontext->ecxt_param_exec_vals[paramid]);
Assert(prmdata->execPlan == NULL);
prmdata->value = slot_getattr(slot, col,
&(prmdata->isnull));
col++;
}
slot = ExecProject(node->projRight, NULL);
/*
* If result contains any nulls, store separately or not at all.
*/
if (slotNoNulls(slot))
{
(void) LookupTupleHashEntry(node->hashtable, slot, &isnew);
node->havehashrows = true;
}
else if (node->hashnulls)
{
(void) LookupTupleHashEntry(node->hashnulls, slot, &isnew);
node->havenullrows = true;
}
/*
* Reset innerecontext after each inner tuple to free any memory used
* in hash computation or comparison routines.
*/
ResetExprContext(innerecontext);
}
/*
* Since the projected tuples are in the sub-query's context and not the
* main context, we'd better clear the tuple slot before there's any
* chance of a reset of the sub-query's context. Else we will have the
* potential for a double free attempt. (XXX possibly no longer needed,
* but can't hurt.)
*/
ExecClearTuple(node->projRight->pi_slot);
MemoryContextSwitchTo(oldcontext);
}
/*
* findPartialMatch: does the hashtable contain an entry that is not
* provably distinct from the tuple?
*
* We have to scan the whole hashtable; we can't usefully use hashkeys
* to guide probing, since we might get partial matches on tuples with
* hashkeys quite unrelated to what we'd get from the given tuple.
*/
static bool
findPartialMatch(TupleHashTable hashtable, TupleTableSlot *slot)
{
int numCols = hashtable->numCols;
AttrNumber *keyColIdx = hashtable->keyColIdx;
TupleHashIterator hashiter;
TupleHashEntry entry;
InitTupleHashIterator(hashtable, &hashiter);
while ((entry = ScanTupleHashTable(&hashiter)) != NULL)
{
ExecStoreMemTuple(entry->firstTuple, hashtable->tableslot, false);
if (!execTuplesUnequal(hashtable->tableslot, slot,
numCols, keyColIdx,
hashtable->eqfunctions,
hashtable->tempcxt))
{
TermTupleHashIterator(&hashiter);
return true;
}
}
/* No TermTupleHashIterator call needed here */
return false;
}
/*
* slotAllNulls: is the slot completely NULL?
*
* This does not test for dropped columns, which is OK because we only
* use it on projected tuples.
*/
static bool
slotAllNulls(TupleTableSlot *slot)
{
int ncols = slot->tts_tupleDescriptor->natts;
int i;
for (i = 1; i <= ncols; i++)
{
if (!slot_attisnull(slot, i))
return false;
}
return true;
}
/*
* slotNoNulls: is the slot entirely not NULL?
*
* This does not test for dropped columns, which is OK because we only
* use it on projected tuples.
*/
static bool
slotNoNulls(TupleTableSlot *slot)
{
int ncols = slot->tts_tupleDescriptor->natts;
int i;
for (i = 1; i <= ncols; i++)
{
if (slot_attisnull(slot, i))
return false;
}
return true;
}
/* ----------------------------------------------------------------
* ExecInitSubPlan
*
* Note: the eflags are those passed to the parent plan node of this
* subplan; they don't directly describe the execution conditions the
* subplan will face.
* ----------------------------------------------------------------
*/
void
ExecInitSubPlan(SubPlanState *node, EState *estate, int eflags)
{
SubPlan *subplan = (SubPlan *) node->xprstate.expr;
EState *sp_estate;
/*
* initialize my state
*/
node->needShutdown = false;
node->curTuple = NULL;
node->projLeft = NULL;
node->projRight = NULL;
node->hashtable = NULL;
node->hashnulls = NULL;
node->hashtablecxt = NULL;
node->hashtempcxt = NULL;
node->innerecontext = NULL;
node->keyColIdx = NULL;
node->eqfunctions = NULL;
node->hashfunctions = NULL;
node->cdbextratextbuf = NULL;
/*
* create an EState for the subplan
*
* The subquery needs its own EState because it has its own rangetable. It
* shares our Param ID space and es_query_cxt, however. XXX if rangetable
* access were done differently, the subquery could share our EState,
* which would eliminate some thrashing about in this module...
*/
sp_estate = CreateSubExecutorState(estate);
node->sub_estate = sp_estate;
sp_estate->es_range_table = estate->es_range_table;
sp_estate->es_plannedstmt = estate->es_plannedstmt;
sp_estate->es_param_list_info = estate->es_param_list_info;
sp_estate->es_param_exec_vals = estate->es_param_exec_vals;
sp_estate->es_tupleTable =
ExecCreateTupleTable(ExecCountSlotsNode(exec_subplan_get_plan(sp_estate->es_plannedstmt, subplan)) + 10);
sp_estate->es_snapshot = estate->es_snapshot;
sp_estate->es_crosscheck_snapshot = estate->es_crosscheck_snapshot;
sp_estate->es_instrument = estate->es_instrument;
sp_estate->es_sliceTable = estate->es_sliceTable;
sp_estate->currentSliceIdInPlan = estate->currentSliceIdInPlan;
sp_estate->currentExecutingSliceId = estate->currentExecutingSliceId;
sp_estate->rootSliceId = estate->currentExecutingSliceId;
sp_estate->motionlayer_context = estate->motionlayer_context;
sp_estate->es_sharenode = estate->es_sharenode;
/*
* Start up the subplan (this is a very cut-down form of InitPlan())
*
* The subplan will never need to do BACKWARD scan or MARK/RESTORE.
*
* We set the REWIND flag to notify the subplan that it is likely to be
* rescanned, and it must delay eagerfree.
*/
eflags &= EXEC_FLAG_EXPLAIN_ONLY;
eflags |= EXEC_FLAG_REWIND;
Plan *subplanplan = exec_subplan_get_plan(estate->es_plannedstmt, subplan);
Assert(subplanplan);
Assert(node->planstate == NULL);
node->planstate = ExecInitNode(subplanplan, sp_estate, eflags);
node->needShutdown = true; /* now we need to shutdown the subplan */
/*
* If this plan is un-correlated or undirect correlated one and want to
* set params for parent plan then mark parameters as needing evaluation.
*
* Note that in the case of un-correlated subqueries we don't care about
* setting parent->chgParam here: indices take care about it, for others -
* it doesn't matter...
*/
if (subplan->setParam != NIL)
{
ListCell *lst;
foreach(lst, subplan->setParam)
{
int paramid = lfirst_int(lst);
ParamExecData *prmExec = &(estate->es_param_exec_vals[paramid]);
/**
* Has this parameter been already
* evaluated as part of preprocess_initplan()? If so,
* we shouldn't re-evaluate it. If it has been evaluated,
* we will simply substitute the actual value from
* the external parameters.
*/
if (Gp_role == GP_ROLE_EXECUTE
&& subplan->is_initplan)
{
ParamListInfo paramInfo = estate->es_param_list_info;
ParamExternData *prmExt = NULL;
int extParamIndex = -1;
Assert(paramInfo);
Assert(paramInfo->numParams > 0);
/*
* To locate the value of this pre-evaluated parameter, we need to find
* its location in the external parameter list.
*/
extParamIndex = paramInfo->numParams - estate->es_plannedstmt->nCrossLevelParams + paramid;
/* Ensure that the plan is actually an initplan */
Assert(subplan->is_initplan && "Subplan is not an initplan. Parameter has not been evaluated in preprocess_initplan.");
prmExt = &paramInfo->params[extParamIndex];
/* Make sure the types are valid */
Assert(OidIsValid(prmExt->ptype) && "Invalid Oid for pre-evaluated parameter.");
/** Hurray! Copy value from external parameter and don't bother setting up execPlan. */
prmExec->execPlan = NULL;
prmExec->isnull = prmExt->isnull;
prmExec->value = prmExt->value;
}
else
{
prmExec->execPlan = node;
}
}
}
/*
* If we are going to hash the subquery output, initialize relevant stuff.
* (We don't create the hashtable until needed, though.)
*/
if (subplan->useHashTable)
{
int ncols,
i;
TupleDesc tupDesc;
TupleTable tupTable;
TupleTableSlot *slot;
List *oplist,
*lefttlist,
*righttlist,
*leftptlist,
*rightptlist;
ListCell *l;
/* We need a memory context to hold the hash table(s) */
node->hashtablecxt =
AllocSetContextCreate(CurrentMemoryContext,
"Subplan HashTable Context",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
/* and a small one for the hash tables to use as temp storage */
node->hashtempcxt =
AllocSetContextCreate(CurrentMemoryContext,
"Subplan HashTable Temp Context",
ALLOCSET_SMALL_MINSIZE,
ALLOCSET_SMALL_INITSIZE,
ALLOCSET_SMALL_MAXSIZE);
/* and a short-lived exprcontext for function evaluation */
node->innerecontext = CreateExprContext(estate);
/* Silly little array of column numbers 1..n */
ncols = list_length(subplan->paramIds);
node->keyColIdx = (AttrNumber *) palloc(ncols * sizeof(AttrNumber));
for (i = 0; i < ncols; i++)
node->keyColIdx[i] = i + 1;
/*
* We use ExecProject to evaluate the lefthand and righthand
* expression lists and form tuples. (You might think that we could
* use the sub-select's output tuples directly, but that is not the
* case if we had to insert any run-time coercions of the sub-select's
* output datatypes; anyway this avoids storing any resjunk columns
* that might be in the sub-select's output.) Run through the
* combining expressions to build tlists for the lefthand and
* righthand sides. We need both the ExprState list (for ExecProject)
* and the underlying parse Exprs (for ExecTypeFromTL).
*
* We also extract the combining operators themselves to initialize
* the equality and hashing functions for the hash tables.
*/
if (IsA(node->testexpr->expr, OpExpr))
{
/* single combining operator */
oplist = list_make1(node->testexpr);
}
else if (and_clause((Node *) node->testexpr->expr))
{
/* multiple combining operators */
Assert(IsA(node->testexpr, BoolExprState));
oplist = ((BoolExprState *) node->testexpr)->args;
}
else
{
/* shouldn't see anything else in a hashable subplan */
insist_log(false, "unrecognized testexpr type: %d",
(int) nodeTag(node->testexpr->expr));
oplist = NIL; /* keep compiler quiet */
}
Assert(list_length(oplist) == ncols);
lefttlist = righttlist = NIL;
leftptlist = rightptlist = NIL;
node->eqfunctions = (FmgrInfo *) palloc(ncols * sizeof(FmgrInfo));
node->hashfunctions = (FmgrInfo *) palloc(ncols * sizeof(FmgrInfo));
i = 1;
foreach(l, oplist)
{
FuncExprState *fstate = (FuncExprState *) lfirst(l);
OpExpr *opexpr = (OpExpr *) fstate->xprstate.expr;
ExprState *exstate;
Expr *expr;
TargetEntry *tle;
GenericExprState *tlestate;
Oid hashfn;
Assert(IsA(fstate, FuncExprState));
Assert(IsA(opexpr, OpExpr));
Assert(list_length(fstate->args) == 2);
/* Process lefthand argument */
exstate = (ExprState *) linitial(fstate->args);
expr = exstate->expr;
tle = makeTargetEntry(expr,
i,
NULL,
false);
tlestate = makeNode(GenericExprState);
tlestate->xprstate.expr = (Expr *) tle;
tlestate->xprstate.evalfunc = NULL;
tlestate->arg = exstate;
lefttlist = lappend(lefttlist, tlestate);
leftptlist = lappend(leftptlist, tle);
/* Process righthand argument */
exstate = (ExprState *) lsecond(fstate->args);
expr = exstate->expr;
tle = makeTargetEntry(expr,
i,
NULL,
false);
tlestate = makeNode(GenericExprState);
tlestate->xprstate.expr = (Expr *) tle;
tlestate->xprstate.evalfunc = NULL;
tlestate->arg = exstate;
righttlist = lappend(righttlist, tlestate);
rightptlist = lappend(rightptlist, tle);
/* Lookup the combining function */
fmgr_info(opexpr->opfuncid, &node->eqfunctions[i - 1]);
node->eqfunctions[i - 1].fn_expr = (Node *) opexpr;
/* Lookup the associated hash function */
hashfn = get_op_hash_function(opexpr->opno);
if (!OidIsValid(hashfn))
elog(ERROR, "could not find hash function for hash operator %u",
opexpr->opno);
fmgr_info(hashfn, &node->hashfunctions[i - 1]);
i++;
}
/*
* Create a tupletable to hold these tuples. (Note: we never bother
* to free the tupletable explicitly; that's okay because it will
* never store raw disk tuples that might have associated buffer pins.
* The only resource involved is memory, which will be cleaned up by
* freeing the query context.)
*/
tupTable = ExecCreateTupleTable(2);
/*
* Construct tupdescs, slots and projection nodes for left and right
* sides. The lefthand expressions will be evaluated in the parent
* plan node's exprcontext, which we don't have access to here.
* Fortunately we can just pass NULL for now and fill it in later
* (hack alert!). The righthand expressions will be evaluated in our
* own innerecontext.
*/
tupDesc = ExecTypeFromTL(leftptlist, false);
slot = ExecAllocTableSlot(tupTable);
ExecSetSlotDescriptor(slot, tupDesc);
node->projLeft = ExecBuildProjectionInfo(lefttlist,
NULL,
slot,
NULL);
tupDesc = ExecTypeFromTL(rightptlist, false);
slot = ExecAllocTableSlot(tupTable);
ExecSetSlotDescriptor(slot, tupDesc);
node->projRight = ExecBuildProjectionInfo(righttlist,
node->innerecontext,
slot,
NULL);
}
}
/* ----------------------------------------------------------------
* ExecSetParamPlan
*
* Executes an InitPlan subplan and sets its output parameters.
*
* This is called from ExecEvalParam() when the value of a PARAM_EXEC
* parameter is requested and the param's execPlan field is set (indicating
* that the param has not yet been evaluated). This allows lazy evaluation
* of initplans: we don't run the subplan until/unless we need its output.
* Note that this routine MUST clear the execPlan fields of the plan's
* output parameters after evaluating them!
* ----------------------------------------------------------------
*/
/*
* Greenplum Database Changes:
* In the case where this is running on the dispatcher, and it's a parallel dispatch
* subplan, we need to dispatch the query to the qExecs as well, like in ExecutorRun.
* except in this case we don't have to worry about insert statements.
* In order to serialize the parameters (including PARAM_EXEC parameters that
* are converted into PARAM_EXEC_REMOTE parameters, I had to add a parameter to this
* function: ParamListInfo p. This may be NULL in the non-dispatch case.
*/
/* Helper: SubplanQueryDesc derives a QueryDesc for use by the subplan. */
static QueryDesc *SubplanQueryDesc(QueryDesc * qd)
{
QueryDesc *subqd = NULL;
PlannedStmt *substmt = NULL;
PlannedStmt *stmt = qd->plannedstmt;
Assert(stmt != NULL);
/*
* MPP-2869 and MPP-2859, single-row parameter-subquery inside
* CTAS: we don't want to create the the table during the
* initPlan execution. */
/* build the PlannedStmt substmt */
substmt = makeNode(PlannedStmt);
substmt->commandType = stmt->commandType;
substmt->canSetTag = stmt->canSetTag;
substmt->transientPlan = stmt->transientPlan;
substmt->planTree = stmt->planTree;
substmt->rtable = stmt->rtable;
substmt->resultRelations = stmt->resultRelations;
substmt->utilityStmt = stmt->utilityStmt;
substmt->intoClause = NULL;
substmt->subplans = stmt->subplans;
substmt->rewindPlanIDs = stmt->rewindPlanIDs;
substmt->returningLists = stmt->returningLists;
substmt->rowMarks = stmt->rowMarks;
substmt->relationOids = stmt->relationOids;
substmt->invalItems = stmt->invalItems;
substmt->nCrossLevelParams = stmt->nCrossLevelParams;
substmt->nMotionNodes = stmt->nMotionNodes;
substmt->nInitPlans = stmt->nInitPlans;
substmt->contextdisp = stmt->contextdisp;
substmt->scantable_splits = stmt->scantable_splits;
substmt->resource = stmt->resource;
/*
* Fake a QueryDesc stucture for CdbDispatchPlan call. It should
* look like the one passed in as the argument which carries the
* global query, plan, parameters, and slice table, and specifies
* the initplan root of interest.
*/
subqd = CreateQueryDesc(substmt,
pstrdup("(internal SELECT query for initplan)"),
qd->snapshot,
qd->crosscheck_snapshot,
NULL, /* Null destination for the QE */
qd->params,
qd->doInstrument);
return subqd;
}
void
ExecSetParamPlan(SubPlanState *node, ExprContext *econtext, QueryDesc *gbl_queryDesc)
{
SubPlan *subplan = (SubPlan *) node->xprstate.expr;
PlanState *planstate = node->planstate;
SubLinkType subLinkType = subplan->subLinkType;
MemoryContext oldcontext = CurrentMemoryContext;
TupleTableSlot *slot;
ListCell *l;
bool found = false;
ArrayBuildState *astate = NULL;
Size savepeakspace = MemoryContextGetPeakSpace(planstate->state->es_query_cxt);
QueryDesc *queryDesc = NULL;
bool shouldDispatch = false;
volatile bool shouldTeardownInterconnect = false;
volatile bool explainRecvStats = false;
if (Gp_role == GP_ROLE_DISPATCH &&
planstate != NULL &&
planstate->plan != NULL &&
planstate->plan->dispatch == DISPATCH_PARALLEL)
shouldDispatch = true;
node->cdbextratextbuf = NULL;
/*
* Reset memory high-water mark so EXPLAIN ANALYZE can report each
* root slice's usage separately.
*/
MemoryContextSetPeakSpace(planstate->state->es_query_cxt, 0);
/*
* Let's initialize 'queryDesc' before our PG_TRY, to ensure the correct
* value will be seen inside the PG_CATCH block without having to declare
* it 'volatile'. (setjmp/longjmp foolishness)
*/
if (shouldDispatch)
{
/*
* Fake a QueryDesc stucture for CdbDispatchPlan call. It should
* look like the one passed in as the argument which carries the
* global query, plan, parameters, and slice table, and specifies
* the initplan root of interest.
*/
queryDesc = SubplanQueryDesc(gbl_queryDesc);
/*
* CDB TODO: Should this use CreateSubExecutorState()?
* Should FreeExecutorState() eventually be called?
* Why do we need this at all? ... kh 4/2007
*/
queryDesc->estate = CreateExecutorState();
queryDesc->showstatctx = gbl_queryDesc->showstatctx;
queryDesc->estate->showstatctx = gbl_queryDesc->showstatctx;
queryDesc->estate->es_sliceTable = gbl_queryDesc->estate->es_sliceTable;
queryDesc->estate->es_param_exec_vals = gbl_queryDesc->estate->es_param_exec_vals;
queryDesc->estate->motionlayer_context = gbl_queryDesc->estate->motionlayer_context;
queryDesc->extended_query = gbl_queryDesc->extended_query;
queryDesc->resource = gbl_queryDesc->resource;
queryDesc->planner_segments = gbl_queryDesc->planner_segments;
}
/*
* Need a try/catch block here so that if an ereport is called from
* within ExecutePlan, we can clean up by calling CdbCheckDispatchResult.
* This cleans up the asynchronous commands running through the threads launched from
* CdbDispatchCommand.
*/
PG_TRY();
{
if (shouldDispatch)
{
/*
* This call returns after launching the threads that send the
* command to the appropriate segdbs. It does not wait for them
* to finish unless an error is detected before all are dispatched.
*/
queryDesc->estate->dispatch_data = initialize_dispatch_data(queryDesc->resource, false);
prepare_dispatch_query_desc(queryDesc->estate->dispatch_data, queryDesc);
dispatch_run(queryDesc->estate->dispatch_data);
cleanup_dispatch_data(queryDesc->estate->dispatch_data);
/*
* Set up the interconnect for execution of the initplan root slice.
*/
shouldTeardownInterconnect = true;
Assert(!(queryDesc->estate->interconnect_context));
SetupInterconnect(queryDesc->estate);
Assert((queryDesc->estate->interconnect_context));
ExecUpdateTransportState(planstate, queryDesc->estate->interconnect_context);
}
/*
* Must switch to child query's per-query memory context.
*/
oldcontext = MemoryContextSwitchTo(node->sub_estate->es_query_cxt);
if (subLinkType == ANY_SUBLINK ||
subLinkType == ALL_SUBLINK)
elog(ERROR, "ANY/ALL subselect unsupported as initplan");
/*
* By definition, an initplan has no parameters from our query level, but
* it could have some from an outer level. Rescan it if needed.
*/
if (planstate->chgParam != NULL)
ExecReScan(planstate, NULL);
for (slot = ExecProcNode(planstate);
!TupIsNull(slot);
slot = ExecProcNode(planstate))
{
int i = 1;
if (subLinkType == EXISTS_SUBLINK || subLinkType == NOT_EXISTS_SUBLINK)
{
/* There can be only one param... */
int paramid = linitial_int(subplan->setParam);
ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
prm->execPlan = NULL;
bool val = true;
if (subLinkType == NOT_EXISTS_SUBLINK)
{
val = false;
}
prm->value = BoolGetDatum(val);
prm->isnull = false;
found = true;
if (shouldDispatch)
{
/* Tell MPP we're done with this plan. */
ExecSquelchNode(planstate);
}
break;
}
if (subLinkType == ARRAY_SUBLINK)
{
Datum dvalue;
bool disnull;
found = true;
/* stash away current value */
Assert(subplan->firstColType == slot->tts_tupleDescriptor->attrs[0]->atttypid);
dvalue = slot_getattr(slot, 1, &disnull);
astate = accumArrayResult(astate, dvalue, disnull,
subplan->firstColType, oldcontext);
/* keep scanning subplan to collect all values */
continue;
}
if (found &&
(subLinkType == EXPR_SUBLINK ||
subLinkType == ROWCOMPARE_SUBLINK))
ereport(ERROR,
(errcode(ERRCODE_CARDINALITY_VIOLATION),
errmsg("more than one row returned by a subquery used as an expression")));
found = true;
/*
* We need to copy the subplan's tuple into our own context, in case
* any of the params are pass-by-ref type --- the pointers stored in
* the param structs will point at this copied tuple! node->curTuple
* keeps track of the copied tuple for eventual freeing.
*/
MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
if (node->curTuple)
pfree(node->curTuple);
node->curTuple = ExecCopySlotMemTuple(slot);
MemoryContextSwitchTo(node->sub_estate->es_query_cxt);
/*
* Now set all the setParam params from the columns of the tuple
*/
foreach(l, subplan->setParam)
{
int paramid = lfirst_int(l);
ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
prm->execPlan = NULL;
prm->value = memtuple_getattr(node->curTuple, slot->tts_mt_bind, i, &(prm->isnull));
i++;
}
}
if (!found)
{
if (subLinkType == EXISTS_SUBLINK || subLinkType == NOT_EXISTS_SUBLINK)
{
/* There can be only one param... */
int paramid = linitial_int(subplan->setParam);
ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
prm->execPlan = NULL;
bool val = false;
if (subLinkType == NOT_EXISTS_SUBLINK)
{
val = true;
}
prm->value = BoolGetDatum(val);
prm->isnull = false;
}
else
{
foreach(l, subplan->setParam)
{
int paramid = lfirst_int(l);
ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
prm->execPlan = NULL;
prm->value = (Datum) 0;
prm->isnull = true;
}
}
}
else if (subLinkType == ARRAY_SUBLINK)
{
/* There can be only one param... */
int paramid = linitial_int(subplan->setParam);
ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
Assert(astate != NULL);
prm->execPlan = NULL;
/* We build the result in query context so it won't disappear */
prm->value = makeArrayResult(astate, econtext->ecxt_per_query_memory);
prm->isnull = false;
}
/*
* If we dispatched to QEs, wait for completion and check for errors.
*/
if (shouldDispatch &&
queryDesc && queryDesc->estate &&
queryDesc->estate->dispatch_data)
{
/* If EXPLAIN ANALYZE, collect execution stats from qExecs. */
if (planstate->instrument)
{
MemoryContext savecxt;
/* Wait for all gangs to finish. */
dispatch_wait(queryDesc->estate->dispatch_data);
/* Allocate buffer to pass extra message text to cdbexplain. */
savecxt = MemoryContextSwitchTo(gbl_queryDesc->estate->es_query_cxt);
node->cdbextratextbuf = makeStringInfo();
MemoryContextSwitchTo(savecxt);
/* Jam stats into subplan's Instrumentation nodes. */
explainRecvStats = true;
cdbexplain_recvExecStats(planstate,
dispatch_get_results(queryDesc->estate->dispatch_data),
LocallyExecutingSliceIndex(queryDesc->estate),
econtext->ecxt_estate->showstatctx,
dispatch_get_segment_num(queryDesc->estate->dispatch_data));
}
/*
* Wait for all gangs to finish. Check and free the results.
* If the dispatcher or any QE had an error, report it and
* exit to our error handler (below) via PG_THROW.
*/
dispatch_wait(queryDesc->estate->dispatch_data);
dispatch_cleanup(queryDesc->estate->dispatch_data);
queryDesc->estate->dispatch_data = NULL;
}
/* teardown the sequence server */
TeardownSequenceServer();
/* Clean up the interconnect. */
if (shouldTeardownInterconnect)
{
shouldTeardownInterconnect = false;
TeardownInterconnect(queryDesc->estate->interconnect_context,
queryDesc->estate->motionlayer_context,
false); /* following success on QD */
}
}
PG_CATCH();
{
/* If EXPLAIN ANALYZE, collect local and distributed execution stats. */
if (planstate->instrument)
{
cdbexplain_localExecStats(planstate, econtext->ecxt_estate->showstatctx);
if (!explainRecvStats &&
shouldDispatch)
{
Assert(queryDesc != NULL &&
queryDesc->estate != NULL);
/* Wait for all gangs to finish. Cancel slowpokes. */
dispatch_wait(queryDesc->estate->dispatch_data);
cdbexplain_recvExecStats(planstate,
dispatch_get_results(queryDesc->estate->dispatch_data),
LocallyExecutingSliceIndex(queryDesc->estate),
econtext->ecxt_estate->showstatctx,
dispatch_get_segment_num(queryDesc->estate->dispatch_data));
}
}
/* Restore memory high-water mark for root slice of main query. */
MemoryContextSetPeakSpace(planstate->state->es_query_cxt, savepeakspace);
/*
* Request any commands still executing on qExecs to stop.
* Wait for them to finish and clean up the dispatching structures.
* Replace current error info with QE error info if more interesting.
*/
if (shouldDispatch && queryDesc && queryDesc->estate && queryDesc->estate->dispatch_data)
dispatch_catch_error(queryDesc->estate->dispatch_data);
/* teardown the sequence server */
TeardownSequenceServer();
/*
* Clean up the interconnect.
* CDB TODO: Is this needed following failure on QD?
*/
if (shouldTeardownInterconnect)
TeardownInterconnect(queryDesc->estate->interconnect_context,
queryDesc->estate->motionlayer_context,
true);
PG_RE_THROW();
}
PG_END_TRY();
/* If EXPLAIN ANALYZE, collect local execution stats. */
if (planstate->instrument)
cdbexplain_localExecStats(planstate, econtext->ecxt_estate->showstatctx);
/* Restore memory high-water mark for root slice of main query. */
MemoryContextSetPeakSpace(planstate->state->es_query_cxt, savepeakspace);
MemoryContextSwitchTo(oldcontext);
}
/* ----------------------------------------------------------------
* ExecEndSubPlan
* ----------------------------------------------------------------
*/
void
ExecEndSubPlan(SubPlanState *node)
{
if (node->needShutdown)
{
ExecEndPlan(node->planstate, node->sub_estate);
FreeExecutorState(node->sub_estate);
node->sub_estate = NULL;
node->planstate = NULL;
node->needShutdown = false;
}
}
/*
* Mark an initplan as needing recalculation
*/
void
ExecReScanSetParamPlan(SubPlanState *node, PlanState *parent)
{
PlanState *planstate = node->planstate;
SubPlan *subplan = (SubPlan *) node->xprstate.expr;
EState *estate = parent->state;
ListCell *l;
/* sanity checks */
insist_log(subplan->parParam == NIL,
"direct correlated subquery unsupported as initplan");
insist_log(subplan->setParam != NIL,
"setParam list of initplan is empty");
insist_log(!bms_is_empty(planstate->plan->extParam),
"extParam set of initplan is empty");
/*
* Don't actually re-scan: ExecSetParamPlan does it if needed.
*/
/*
* Mark this subplan's output parameters as needing recalculation
*/
foreach(l, subplan->setParam)
{
int paramid = lfirst_int(l);
ParamExecData *prm = &(estate->es_param_exec_vals[paramid]);
prm->execPlan = node;
parent->chgParam = bms_add_member(parent->chgParam, paramid);
}
}
void
ExecEagerFreeSubPlan(SubPlanState *node)
{
Assert(node->hashtablecxt != NULL);
MemoryContextReset(node->hashtablecxt);
node->hashtable = NULL;
node->hashnulls = NULL;
node->havehashrows = false;
node->havenullrows = false;
}