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730840c9b6
expressions, ARRAY(sub-SELECT) expressions, some array functions. Polymorphic functions using ANYARRAY/ANYELEMENT argument and return types. Some regression tests in place, documentation is lacking. Joe Conway, with some kibitzing from Tom Lane.
1186 lines
34 KiB
C
1186 lines
34 KiB
C
/*-------------------------------------------------------------------------
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*
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* nodeSubplan.c
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* routines to support subselects
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*
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* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/executor/nodeSubplan.c,v 1.45 2003/04/08 23:20:01 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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/*
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* INTERFACE ROUTINES
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* ExecSubPlan - process a subselect
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* ExecInitSubPlan - initialize a subselect
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* ExecEndSubPlan - shut down a subselect
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*/
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#include "postgres.h"
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#include "access/heapam.h"
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#include "executor/executor.h"
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#include "executor/nodeSubplan.h"
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#include "nodes/makefuncs.h"
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#include "parser/parse_expr.h"
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#include "utils/array.h"
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#include "utils/datum.h"
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#include "utils/lsyscache.h"
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typedef struct ArrayBuildState
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{
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MemoryContext mcontext; /* where all the temp stuff is kept */
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Datum *dvalues; /* array of accumulated Datums */
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/*
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* The allocated size of dvalues[] is always a multiple of
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* ARRAY_ELEMS_CHUNKSIZE
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*/
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#define ARRAY_ELEMS_CHUNKSIZE 64
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int nelems; /* number of valid Datums in dvalues[] */
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Oid element_type; /* data type of the Datums */
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int16 typlen; /* needed info about datatype */
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bool typbyval;
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char typalign;
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} ArrayBuildState;
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static Datum ExecHashSubPlan(SubPlanState *node,
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ExprContext *econtext,
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bool *isNull);
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static Datum ExecScanSubPlan(SubPlanState *node,
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ExprContext *econtext,
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bool *isNull);
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static void buildSubPlanHash(SubPlanState *node);
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static bool findPartialMatch(TupleHashTable hashtable, TupleTableSlot *slot);
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static bool tupleAllNulls(HeapTuple tuple);
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static ArrayBuildState *accumArrayResult(ArrayBuildState *astate,
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Datum dvalue, bool disnull,
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Oid element_type,
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MemoryContext rcontext);
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static Datum makeArrayResult(ArrayBuildState *astate,
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MemoryContext rcontext);
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/* ----------------------------------------------------------------
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* ExecSubPlan
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* ----------------------------------------------------------------
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*/
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Datum
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ExecSubPlan(SubPlanState *node,
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ExprContext *econtext,
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bool *isNull)
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{
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SubPlan *subplan = (SubPlan *) node->xprstate.expr;
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if (subplan->setParam != NIL)
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elog(ERROR, "ExecSubPlan: can't set parent params from subquery");
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if (subplan->useHashTable)
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return ExecHashSubPlan(node, econtext, isNull);
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else
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return ExecScanSubPlan(node, econtext, isNull);
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}
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/*
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* ExecHashSubPlan: store subselect result in an in-memory hash table
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*/
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static Datum
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ExecHashSubPlan(SubPlanState *node,
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ExprContext *econtext,
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bool *isNull)
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{
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SubPlan *subplan = (SubPlan *) node->xprstate.expr;
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PlanState *planstate = node->planstate;
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ExprContext *innerecontext = node->innerecontext;
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TupleTableSlot *slot;
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HeapTuple tup;
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/* Shouldn't have any direct correlation Vars */
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if (subplan->parParam != NIL || node->args != NIL)
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elog(ERROR, "ExecHashSubPlan: direct correlation not supported");
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/*
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* If first time through or we need to rescan the subplan, build
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* the hash table.
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*/
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if (node->hashtable == NULL || planstate->chgParam != NULL)
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buildSubPlanHash(node);
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/*
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* The result for an empty subplan is always FALSE; no need to
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* evaluate lefthand side.
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*/
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*isNull = false;
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if (!node->havehashrows && !node->havenullrows)
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return BoolGetDatum(false);
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/*
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* Evaluate lefthand expressions and form a projection tuple.
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* First we have to set the econtext to use (hack alert!).
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*/
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node->projLeft->pi_exprContext = econtext;
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slot = ExecProject(node->projLeft, NULL);
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tup = slot->val;
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/*
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* Note: because we are typically called in a per-tuple context,
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* we have to explicitly clear the projected tuple before returning.
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* Otherwise, we'll have a double-free situation: the per-tuple context
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* will probably be reset before we're called again, and then the tuple
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* slot will think it still needs to free the tuple.
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*/
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/*
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* Since the hashtable routines will use innerecontext's per-tuple
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* memory as working memory, be sure to reset it for each tuple.
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*/
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ResetExprContext(innerecontext);
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/*
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* If the LHS is all non-null, probe for an exact match in the
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* main hash table. If we find one, the result is TRUE.
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* Otherwise, scan the partly-null table to see if there are any
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* rows that aren't provably unequal to the LHS; if so, the result
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* is UNKNOWN. (We skip that part if we don't care about UNKNOWN.)
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* Otherwise, the result is FALSE.
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*
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* Note: the reason we can avoid a full scan of the main hash table
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* is that the combining operators are assumed never to yield NULL
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* when both inputs are non-null. If they were to do so, we might
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* need to produce UNKNOWN instead of FALSE because of an UNKNOWN
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* result in comparing the LHS to some main-table entry --- which
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* is a comparison we will not even make, unless there's a chance
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* match of hash keys.
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*/
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if (HeapTupleNoNulls(tup))
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{
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if (node->havehashrows &&
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LookupTupleHashEntry(node->hashtable, slot, NULL) != NULL)
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{
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ExecClearTuple(slot);
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return BoolGetDatum(true);
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}
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if (node->havenullrows &&
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findPartialMatch(node->hashnulls, slot))
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{
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ExecClearTuple(slot);
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*isNull = true;
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return BoolGetDatum(false);
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}
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ExecClearTuple(slot);
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return BoolGetDatum(false);
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}
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/*
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* When the LHS is partly or wholly NULL, we can never return TRUE.
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* If we don't care about UNKNOWN, just return FALSE. Otherwise,
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* if the LHS is wholly NULL, immediately return UNKNOWN. (Since the
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* combining operators are strict, the result could only be FALSE if the
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* sub-select were empty, but we already handled that case.) Otherwise,
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* we must scan both the main and partly-null tables to see if there are
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* any rows that aren't provably unequal to the LHS; if so, the result is
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* UNKNOWN. Otherwise, the result is FALSE.
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*/
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if (node->hashnulls == NULL)
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{
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ExecClearTuple(slot);
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return BoolGetDatum(false);
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}
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if (tupleAllNulls(tup))
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{
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ExecClearTuple(slot);
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*isNull = true;
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return BoolGetDatum(false);
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}
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/* Scan partly-null table first, since more likely to get a match */
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if (node->havenullrows &&
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findPartialMatch(node->hashnulls, slot))
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{
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ExecClearTuple(slot);
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*isNull = true;
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return BoolGetDatum(false);
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}
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if (node->havehashrows &&
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findPartialMatch(node->hashtable, slot))
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{
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ExecClearTuple(slot);
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*isNull = true;
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return BoolGetDatum(false);
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}
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ExecClearTuple(slot);
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return BoolGetDatum(false);
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}
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/*
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* ExecScanSubPlan: default case where we have to rescan subplan each time
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*/
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static Datum
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ExecScanSubPlan(SubPlanState *node,
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ExprContext *econtext,
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bool *isNull)
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{
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SubPlan *subplan = (SubPlan *) node->xprstate.expr;
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PlanState *planstate = node->planstate;
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SubLinkType subLinkType = subplan->subLinkType;
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bool useOr = subplan->useOr;
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MemoryContext oldcontext;
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TupleTableSlot *slot;
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Datum result;
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bool found = false; /* TRUE if got at least one subplan tuple */
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List *pvar;
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List *lst;
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ArrayBuildState *astate = NULL;
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/*
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* We are probably in a short-lived expression-evaluation context.
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* Switch to the child plan's per-query context for manipulating its
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* chgParam, calling ExecProcNode on it, etc.
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*/
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oldcontext = MemoryContextSwitchTo(node->sub_estate->es_query_cxt);
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/*
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* Set Params of this plan from parent plan correlation Vars
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*/
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pvar = node->args;
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foreach(lst, subplan->parParam)
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{
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int paramid = lfirsti(lst);
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ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
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Assert(pvar != NIL);
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prm->value = ExecEvalExprSwitchContext((ExprState *) lfirst(pvar),
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econtext,
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&(prm->isnull),
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NULL);
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pvar = lnext(pvar);
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planstate->chgParam = bms_add_member(planstate->chgParam, paramid);
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}
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Assert(pvar == NIL);
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ExecReScan(planstate, NULL);
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/*
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* For all sublink types except EXPR_SUBLINK and ARRAY_SUBLINK, the result
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* is boolean as are the results of the combining operators. We combine
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* results within a tuple (if there are multiple columns) using OR
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* semantics if "useOr" is true, AND semantics if not. We then combine
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* results across tuples (if the subplan produces more than one) using OR
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* semantics for ANY_SUBLINK or AND semantics for ALL_SUBLINK.
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* (MULTIEXPR_SUBLINK doesn't allow multiple tuples from the subplan.)
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* NULL results from the combining operators are handled according to
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* the usual SQL semantics for OR and AND. The result for no input
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* tuples is FALSE for ANY_SUBLINK, TRUE for ALL_SUBLINK, NULL for
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* MULTIEXPR_SUBLINK.
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*
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* For EXPR_SUBLINK we require the subplan to produce no more than one
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* tuple, else an error is raised. For ARRAY_SUBLINK we allow the subplan
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* to produce more than one tuple. In either case, if zero tuples are
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* produced, we return NULL. Assuming we get a tuple, we just use its
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* first column (there can be only one non-junk column in this case).
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*/
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result = BoolGetDatum(subLinkType == ALL_SUBLINK);
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*isNull = false;
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for (slot = ExecProcNode(planstate);
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!TupIsNull(slot);
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slot = ExecProcNode(planstate))
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{
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HeapTuple tup = slot->val;
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TupleDesc tdesc = slot->ttc_tupleDescriptor;
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Datum rowresult = BoolGetDatum(!useOr);
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bool rownull = false;
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int col = 1;
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List *plst;
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if (subLinkType == EXISTS_SUBLINK)
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{
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found = true;
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result = BoolGetDatum(true);
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break;
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}
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if (subLinkType == EXPR_SUBLINK)
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{
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/* cannot allow multiple input tuples for EXPR sublink */
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if (found)
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elog(ERROR, "More than one tuple returned by a subselect used as an expression.");
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found = true;
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/*
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* We need to copy the subplan's tuple in case the result is
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* of pass-by-ref type --- our return value will point into
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* this copied tuple! Can't use the subplan's instance of the
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* tuple since it won't still be valid after next
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* ExecProcNode() call. node->curTuple keeps track of the
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* copied tuple for eventual freeing.
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*/
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MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
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tup = heap_copytuple(tup);
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if (node->curTuple)
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heap_freetuple(node->curTuple);
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node->curTuple = tup;
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MemoryContextSwitchTo(node->sub_estate->es_query_cxt);
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result = heap_getattr(tup, col, tdesc, isNull);
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/* keep scanning subplan to make sure there's only one tuple */
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continue;
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}
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if (subLinkType == ARRAY_SUBLINK)
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{
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Datum dvalue;
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bool disnull;
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found = true;
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/* stash away current value */
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dvalue = heap_getattr(tup, 1, tdesc, &disnull);
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astate = accumArrayResult(astate, dvalue, disnull,
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tdesc->attrs[0]->atttypid,
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oldcontext);
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/* keep scanning subplan to collect all values */
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continue;
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}
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/* cannot allow multiple input tuples for MULTIEXPR sublink either */
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if (subLinkType == MULTIEXPR_SUBLINK && found)
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elog(ERROR, "More than one tuple returned by a subselect used as an expression.");
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found = true;
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/*
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* For ALL, ANY, and MULTIEXPR sublinks, iterate over combining
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* operators for columns of tuple.
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*/
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plst = subplan->paramIds;
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foreach(lst, node->exprs)
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{
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ExprState *exprstate = (ExprState *) lfirst(lst);
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int paramid = lfirsti(plst);
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ParamExecData *prmdata;
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Datum expresult;
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bool expnull;
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/*
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* Load up the Param representing this column of the sub-select.
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*/
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prmdata = &(econtext->ecxt_param_exec_vals[paramid]);
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Assert(prmdata->execPlan == NULL);
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prmdata->value = heap_getattr(tup, col, tdesc,
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&(prmdata->isnull));
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/*
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* Now we can eval the combining operator for this column.
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*/
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expresult = ExecEvalExprSwitchContext(exprstate, econtext,
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&expnull, NULL);
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/*
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* Combine the result into the row result as appropriate.
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*/
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if (col == 1)
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{
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rowresult = expresult;
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rownull = expnull;
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}
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else if (useOr)
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{
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/* combine within row per OR semantics */
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if (expnull)
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rownull = true;
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else if (DatumGetBool(expresult))
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{
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rowresult = BoolGetDatum(true);
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rownull = false;
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break; /* needn't look at any more columns */
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}
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}
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else
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{
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/* combine within row per AND semantics */
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if (expnull)
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rownull = true;
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else if (!DatumGetBool(expresult))
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{
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rowresult = BoolGetDatum(false);
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rownull = false;
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break; /* needn't look at any more columns */
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}
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}
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plst = lnext(plst);
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col++;
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}
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if (subLinkType == ANY_SUBLINK)
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{
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/* combine across rows per OR semantics */
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if (rownull)
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*isNull = true;
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else if (DatumGetBool(rowresult))
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{
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result = BoolGetDatum(true);
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*isNull = false;
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break; /* needn't look at any more rows */
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}
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}
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else if (subLinkType == ALL_SUBLINK)
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{
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/* combine across rows per AND semantics */
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if (rownull)
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*isNull = true;
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else if (!DatumGetBool(rowresult))
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{
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result = BoolGetDatum(false);
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*isNull = false;
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break; /* needn't look at any more rows */
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}
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}
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else
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{
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/* must be MULTIEXPR_SUBLINK */
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result = rowresult;
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*isNull = rownull;
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}
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}
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if (!found)
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{
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/*
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* deal with empty subplan result. result/isNull were previously
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* initialized correctly for all sublink types except EXPR, ARRAY, and
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* MULTIEXPR; for those, return NULL.
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*/
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if (subLinkType == EXPR_SUBLINK ||
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subLinkType == ARRAY_SUBLINK ||
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subLinkType == MULTIEXPR_SUBLINK)
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{
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result = (Datum) 0;
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*isNull = true;
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}
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}
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else if (subLinkType == ARRAY_SUBLINK)
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{
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Assert(astate != NULL);
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/* We return the result in the caller's context */
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result = makeArrayResult(astate, oldcontext);
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}
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|
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MemoryContextSwitchTo(oldcontext);
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return result;
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}
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|
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/*
|
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* buildSubPlanHash: load hash table by scanning subplan output.
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*/
|
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static void
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buildSubPlanHash(SubPlanState *node)
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{
|
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SubPlan *subplan = (SubPlan *) node->xprstate.expr;
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PlanState *planstate = node->planstate;
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int ncols = length(node->exprs);
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ExprContext *innerecontext = node->innerecontext;
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MemoryContext tempcxt = innerecontext->ecxt_per_tuple_memory;
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MemoryContext oldcontext;
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int nbuckets;
|
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TupleTableSlot *slot;
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Assert(subplan->subLinkType == ANY_SUBLINK);
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Assert(!subplan->useOr);
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/*
|
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* If we already had any hash tables, destroy 'em; then create
|
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* empty hash table(s).
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*
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* If we need to distinguish accurately between FALSE and UNKNOWN
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* (i.e., NULL) results of the IN operation, then we have to store
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* subplan output rows that are partly or wholly NULL. We store such
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* rows in a separate hash table that we expect will be much smaller
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* than the main table. (We can use hashing to eliminate partly-null
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* rows that are not distinct. We keep them separate to minimize the
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* cost of the inevitable full-table searches; see findPartialMatch.)
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*
|
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* If it's not necessary to distinguish FALSE and UNKNOWN, then we
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* don't need to store subplan output rows that contain NULL.
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*/
|
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MemoryContextReset(node->tablecxt);
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node->hashtable = NULL;
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node->hashnulls = NULL;
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node->havehashrows = false;
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node->havenullrows = false;
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|
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nbuckets = (int) ceil(planstate->plan->plan_rows);
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if (nbuckets < 1)
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nbuckets = 1;
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node->hashtable = BuildTupleHashTable(ncols,
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node->keyColIdx,
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node->eqfunctions,
|
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nbuckets,
|
|
sizeof(TupleHashEntryData),
|
|
node->tablecxt,
|
|
tempcxt);
|
|
|
|
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,
|
|
nbuckets,
|
|
sizeof(TupleHashEntryData),
|
|
node->tablecxt,
|
|
tempcxt);
|
|
}
|
|
|
|
/*
|
|
* 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))
|
|
{
|
|
HeapTuple tup = slot->val;
|
|
TupleDesc tdesc = slot->ttc_tupleDescriptor;
|
|
int col = 1;
|
|
List *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 = lfirsti(plst);
|
|
ParamExecData *prmdata;
|
|
|
|
prmdata = &(innerecontext->ecxt_param_exec_vals[paramid]);
|
|
Assert(prmdata->execPlan == NULL);
|
|
prmdata->value = heap_getattr(tup, col, tdesc,
|
|
&(prmdata->isnull));
|
|
col++;
|
|
}
|
|
slot = ExecProject(node->projRight, NULL);
|
|
tup = slot->val;
|
|
|
|
/*
|
|
* If result contains any nulls, store separately or not at all.
|
|
* (Since we know the projection tuple has no junk columns, we
|
|
* can just look at the overall hasnull info bit, instead of
|
|
* groveling through the columns.)
|
|
*/
|
|
if (HeapTupleNoNulls(tup))
|
|
{
|
|
(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.
|
|
*/
|
|
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;
|
|
HeapTuple tuple = slot->val;
|
|
TupleDesc tupdesc = slot->ttc_tupleDescriptor;
|
|
TupleHashIterator hashiter;
|
|
TupleHashEntry entry;
|
|
|
|
ResetTupleHashIterator(&hashiter);
|
|
while ((entry = ScanTupleHashTable(hashtable, &hashiter)) != NULL)
|
|
{
|
|
if (!execTuplesUnequal(entry->firstTuple,
|
|
tuple,
|
|
tupdesc,
|
|
numCols, keyColIdx,
|
|
hashtable->eqfunctions,
|
|
hashtable->tempcxt))
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* tupleAllNulls: is the tuple completely NULL?
|
|
*/
|
|
static bool
|
|
tupleAllNulls(HeapTuple tuple)
|
|
{
|
|
int ncols = tuple->t_data->t_natts;
|
|
int i;
|
|
|
|
for (i = 1; i <= ncols; i++)
|
|
{
|
|
if (!heap_attisnull(tuple, i))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/* ----------------------------------------------------------------
|
|
* ExecInitSubPlan
|
|
* ----------------------------------------------------------------
|
|
*/
|
|
void
|
|
ExecInitSubPlan(SubPlanState *node, EState *estate)
|
|
{
|
|
SubPlan *subplan = (SubPlan *) node->xprstate.expr;
|
|
EState *sp_estate;
|
|
MemoryContext oldcontext;
|
|
|
|
/*
|
|
* Do access checking on the rangetable entries in the subquery.
|
|
* Here, we assume the subquery is a SELECT.
|
|
*/
|
|
ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
|
|
|
|
/*
|
|
* initialize my state
|
|
*/
|
|
node->needShutdown = false;
|
|
node->curTuple = NULL;
|
|
node->projLeft = NULL;
|
|
node->projRight = NULL;
|
|
node->hashtable = NULL;
|
|
node->hashnulls = NULL;
|
|
node->tablecxt = NULL;
|
|
node->innerecontext = NULL;
|
|
node->keyColIdx = NULL;
|
|
node->eqfunctions = 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, 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 = CreateExecutorState();
|
|
node->sub_estate = sp_estate;
|
|
|
|
oldcontext = MemoryContextSwitchTo(sp_estate->es_query_cxt);
|
|
|
|
sp_estate->es_range_table = subplan->rtable;
|
|
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(subplan->plan) + 10);
|
|
sp_estate->es_snapshot = estate->es_snapshot;
|
|
sp_estate->es_instrument = estate->es_instrument;
|
|
|
|
/*
|
|
* Start up the subplan (this is a very cut-down form of InitPlan())
|
|
*/
|
|
node->planstate = ExecInitNode(subplan->plan, sp_estate);
|
|
|
|
node->needShutdown = true; /* now we need to shutdown the subplan */
|
|
|
|
MemoryContextSwitchTo(oldcontext);
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
List *lst;
|
|
|
|
foreach(lst, subplan->setParam)
|
|
{
|
|
int paramid = lfirsti(lst);
|
|
ParamExecData *prm = &(estate->es_param_exec_vals[paramid]);
|
|
|
|
prm->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 *lefttlist,
|
|
*righttlist,
|
|
*leftptlist,
|
|
*rightptlist,
|
|
*lexpr;
|
|
|
|
/* We need a memory context to hold the hash table(s) */
|
|
node->tablecxt =
|
|
AllocSetContextCreate(CurrentMemoryContext,
|
|
"Subplan HashTable Context",
|
|
ALLOCSET_DEFAULT_MINSIZE,
|
|
ALLOCSET_DEFAULT_INITSIZE,
|
|
ALLOCSET_DEFAULT_MAXSIZE);
|
|
/* and a short-lived exprcontext for function evaluation */
|
|
node->innerecontext = CreateExprContext(estate);
|
|
/* Silly little array of column numbers 1..n */
|
|
ncols = length(node->exprs);
|
|
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 functions for the hash tables.
|
|
*/
|
|
lefttlist = righttlist = NIL;
|
|
leftptlist = rightptlist = NIL;
|
|
node->eqfunctions = (FmgrInfo *) palloc(ncols * sizeof(FmgrInfo));
|
|
i = 1;
|
|
foreach(lexpr, node->exprs)
|
|
{
|
|
FuncExprState *fstate = (FuncExprState *) lfirst(lexpr);
|
|
OpExpr *opexpr = (OpExpr *) fstate->xprstate.expr;
|
|
ExprState *exstate;
|
|
Expr *expr;
|
|
TargetEntry *tle;
|
|
GenericExprState *tlestate;
|
|
|
|
Assert(IsA(fstate, FuncExprState));
|
|
Assert(IsA(opexpr, OpExpr));
|
|
Assert(length(fstate->args) == 2);
|
|
|
|
/* Process lefthand argument */
|
|
exstate = (ExprState *) lfirst(fstate->args);
|
|
expr = exstate->expr;
|
|
tle = makeTargetEntry(makeResdom(i,
|
|
exprType((Node *) expr),
|
|
exprTypmod((Node *) expr),
|
|
NULL,
|
|
false),
|
|
expr);
|
|
tlestate = makeNode(GenericExprState);
|
|
tlestate->xprstate.expr = (Expr *) tle;
|
|
tlestate->arg = exstate;
|
|
lefttlist = lappend(lefttlist, tlestate);
|
|
leftptlist = lappend(leftptlist, tle);
|
|
|
|
/* Process righthand argument */
|
|
exstate = (ExprState *) lsecond(fstate->args);
|
|
expr = exstate->expr;
|
|
tle = makeTargetEntry(makeResdom(i,
|
|
exprType((Node *) expr),
|
|
exprTypmod((Node *) expr),
|
|
NULL,
|
|
false),
|
|
expr);
|
|
tlestate = makeNode(GenericExprState);
|
|
tlestate->xprstate.expr = (Expr *) tle;
|
|
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;
|
|
|
|
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, true);
|
|
node->projLeft = ExecBuildProjectionInfo(lefttlist,
|
|
NULL,
|
|
slot);
|
|
|
|
tupDesc = ExecTypeFromTL(rightptlist, false);
|
|
slot = ExecAllocTableSlot(tupTable);
|
|
ExecSetSlotDescriptor(slot, tupDesc, true);
|
|
node->projRight = ExecBuildProjectionInfo(righttlist,
|
|
node->innerecontext,
|
|
slot);
|
|
}
|
|
}
|
|
|
|
/* ----------------------------------------------------------------
|
|
* 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!
|
|
* ----------------------------------------------------------------
|
|
*/
|
|
void
|
|
ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
|
|
{
|
|
SubPlan *subplan = (SubPlan *) node->xprstate.expr;
|
|
PlanState *planstate = node->planstate;
|
|
SubLinkType subLinkType = subplan->subLinkType;
|
|
MemoryContext oldcontext;
|
|
TupleTableSlot *slot;
|
|
List *lst;
|
|
bool found = false;
|
|
ArrayBuildState *astate = NULL;
|
|
|
|
/*
|
|
* 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, "ExecSetParamPlan: ANY/ALL subselect unsupported");
|
|
|
|
if (planstate->chgParam != NULL)
|
|
ExecReScan(planstate, NULL);
|
|
|
|
for (slot = ExecProcNode(planstate);
|
|
!TupIsNull(slot);
|
|
slot = ExecProcNode(planstate))
|
|
{
|
|
HeapTuple tup = slot->val;
|
|
TupleDesc tdesc = slot->ttc_tupleDescriptor;
|
|
int i = 1;
|
|
|
|
if (subLinkType == EXISTS_SUBLINK)
|
|
{
|
|
/* There can be only one param... */
|
|
int paramid = lfirsti(subplan->setParam);
|
|
ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
|
|
|
|
prm->execPlan = NULL;
|
|
prm->value = BoolGetDatum(true);
|
|
prm->isnull = false;
|
|
found = true;
|
|
break;
|
|
}
|
|
|
|
if (subLinkType == ARRAY_SUBLINK)
|
|
{
|
|
Datum dvalue;
|
|
bool disnull;
|
|
|
|
found = true;
|
|
/* stash away current value */
|
|
dvalue = heap_getattr(tup, 1, tdesc, &disnull);
|
|
astate = accumArrayResult(astate, dvalue, disnull,
|
|
tdesc->attrs[0]->atttypid,
|
|
oldcontext);
|
|
/* keep scanning subplan to collect all values */
|
|
continue;
|
|
}
|
|
|
|
if (found &&
|
|
(subLinkType == EXPR_SUBLINK ||
|
|
subLinkType == MULTIEXPR_SUBLINK))
|
|
elog(ERROR, "More than one tuple returned by a subselect 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);
|
|
tup = heap_copytuple(tup);
|
|
if (node->curTuple)
|
|
heap_freetuple(node->curTuple);
|
|
node->curTuple = tup;
|
|
MemoryContextSwitchTo(node->sub_estate->es_query_cxt);
|
|
|
|
/*
|
|
* Now set all the setParam params from the columns of the tuple
|
|
*/
|
|
foreach(lst, subplan->setParam)
|
|
{
|
|
int paramid = lfirsti(lst);
|
|
ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
|
|
|
|
prm->execPlan = NULL;
|
|
prm->value = heap_getattr(tup, i, tdesc, &(prm->isnull));
|
|
i++;
|
|
}
|
|
}
|
|
|
|
if (!found)
|
|
{
|
|
if (subLinkType == EXISTS_SUBLINK)
|
|
{
|
|
/* There can be only one param... */
|
|
int paramid = lfirsti(subplan->setParam);
|
|
ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
|
|
|
|
prm->execPlan = NULL;
|
|
prm->value = BoolGetDatum(false);
|
|
prm->isnull = false;
|
|
}
|
|
else
|
|
{
|
|
foreach(lst, subplan->setParam)
|
|
{
|
|
int paramid = lfirsti(lst);
|
|
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 = lfirsti(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;
|
|
}
|
|
|
|
MemoryContextSwitchTo(oldcontext);
|
|
}
|
|
|
|
/* ----------------------------------------------------------------
|
|
* ExecEndSubPlan
|
|
* ----------------------------------------------------------------
|
|
*/
|
|
void
|
|
ExecEndSubPlan(SubPlanState *node)
|
|
{
|
|
if (node->needShutdown)
|
|
{
|
|
MemoryContext oldcontext;
|
|
|
|
oldcontext = MemoryContextSwitchTo(node->sub_estate->es_query_cxt);
|
|
ExecEndPlan(node->planstate, node->sub_estate);
|
|
MemoryContextSwitchTo(oldcontext);
|
|
FreeExecutorState(node->sub_estate);
|
|
node->sub_estate = NULL;
|
|
node->planstate = NULL;
|
|
node->needShutdown = false;
|
|
}
|
|
}
|
|
|
|
void
|
|
ExecReScanSetParamPlan(SubPlanState *node, PlanState *parent)
|
|
{
|
|
PlanState *planstate = node->planstate;
|
|
SubPlan *subplan = (SubPlan *) node->xprstate.expr;
|
|
EState *estate = parent->state;
|
|
List *lst;
|
|
|
|
if (subplan->parParam != NIL)
|
|
elog(ERROR, "ExecReScanSetParamPlan: direct correlated subquery unsupported, yet");
|
|
if (subplan->setParam == NIL)
|
|
elog(ERROR, "ExecReScanSetParamPlan: setParam list is empty");
|
|
if (bms_is_empty(planstate->plan->extParam))
|
|
elog(ERROR, "ExecReScanSetParamPlan: extParam set of plan is empty");
|
|
|
|
/*
|
|
* Don't actually re-scan: ExecSetParamPlan does it if needed.
|
|
*/
|
|
|
|
/*
|
|
* Mark this subplan's output parameters as needing recalculation
|
|
*/
|
|
foreach(lst, subplan->setParam)
|
|
{
|
|
int paramid = lfirsti(lst);
|
|
ParamExecData *prm = &(estate->es_param_exec_vals[paramid]);
|
|
|
|
prm->execPlan = node;
|
|
parent->chgParam = bms_add_member(parent->chgParam, paramid);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* accumArrayResult - accumulate one (more) Datum for an ARRAY_SUBLINK
|
|
*
|
|
* astate is working state (NULL on first call)
|
|
* rcontext is where to keep working state
|
|
*/
|
|
static ArrayBuildState *
|
|
accumArrayResult(ArrayBuildState *astate,
|
|
Datum dvalue, bool disnull,
|
|
Oid element_type,
|
|
MemoryContext rcontext)
|
|
{
|
|
MemoryContext arr_context,
|
|
oldcontext;
|
|
|
|
if (astate == NULL)
|
|
{
|
|
/* First time through --- initialize */
|
|
|
|
/* Make a temporary context to hold all the junk */
|
|
arr_context = AllocSetContextCreate(rcontext,
|
|
"ARRAY_SUBLINK Result",
|
|
ALLOCSET_DEFAULT_MINSIZE,
|
|
ALLOCSET_DEFAULT_INITSIZE,
|
|
ALLOCSET_DEFAULT_MAXSIZE);
|
|
oldcontext = MemoryContextSwitchTo(arr_context);
|
|
astate = (ArrayBuildState *) palloc(sizeof(ArrayBuildState));
|
|
astate->mcontext = arr_context;
|
|
astate->dvalues = (Datum *)
|
|
palloc(ARRAY_ELEMS_CHUNKSIZE * sizeof(Datum));
|
|
astate->nelems = 0;
|
|
astate->element_type = element_type;
|
|
get_typlenbyvalalign(element_type,
|
|
&astate->typlen,
|
|
&astate->typbyval,
|
|
&astate->typalign);
|
|
}
|
|
else
|
|
{
|
|
oldcontext = MemoryContextSwitchTo(astate->mcontext);
|
|
Assert(astate->element_type == element_type);
|
|
/* enlarge dvalues[] if needed */
|
|
if ((astate->nelems % ARRAY_ELEMS_CHUNKSIZE) == 0)
|
|
astate->dvalues = (Datum *)
|
|
repalloc(astate->dvalues,
|
|
(astate->nelems + ARRAY_ELEMS_CHUNKSIZE) * sizeof(Datum));
|
|
}
|
|
|
|
if (disnull)
|
|
elog(ERROR, "NULL elements not allowed in Arrays");
|
|
|
|
/* Use datumCopy to ensure pass-by-ref stuff is copied into mcontext */
|
|
astate->dvalues[astate->nelems++] =
|
|
datumCopy(dvalue, astate->typbyval, astate->typlen);
|
|
|
|
MemoryContextSwitchTo(oldcontext);
|
|
|
|
return astate;
|
|
}
|
|
|
|
/*
|
|
* makeArrayResult - produce final result of ARRAY_SUBLINK
|
|
*
|
|
* astate is working state (not NULL)
|
|
* rcontext is where to construct result
|
|
*/
|
|
static Datum
|
|
makeArrayResult(ArrayBuildState *astate,
|
|
MemoryContext rcontext)
|
|
{
|
|
ArrayType *result;
|
|
int dims[1];
|
|
int lbs[1];
|
|
MemoryContext oldcontext;
|
|
|
|
/* Build the final array result in rcontext */
|
|
oldcontext = MemoryContextSwitchTo(rcontext);
|
|
|
|
dims[0] = astate->nelems;
|
|
lbs[0] = 1;
|
|
|
|
result = construct_md_array(astate->dvalues,
|
|
1,
|
|
dims,
|
|
lbs,
|
|
astate->element_type,
|
|
astate->typlen,
|
|
astate->typbyval,
|
|
astate->typalign);
|
|
|
|
MemoryContextSwitchTo(oldcontext);
|
|
|
|
/* Clean up all the junk */
|
|
MemoryContextDelete(astate->mcontext);
|
|
|
|
return PointerGetDatum(result);
|
|
}
|