78114cd4d4
and fix_opids processing to a single recursive pass over the plan tree executed at the very tail end of planning, rather than haphazardly here and there at different places. Now that tlist Vars do not get modified until the very end, it's possible to get rid of the klugy var_equal and match_varid partial-matching routines, and just use plain equal() throughout the optimizer. This is a step towards allowing merge and hash joins to be done on expressions instead of only Vars ...
670 lines
17 KiB
C
670 lines
17 KiB
C
/*-------------------------------------------------------------------------
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*
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* nodeAgg.c
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* Routines to handle aggregate nodes.
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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*
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* NOTE
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* The implementation of Agg node has been reworked to handle legal
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* SQL aggregates. (Do not expect POSTQUEL semantics.) -- ay 2/95
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*
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* IDENTIFICATION
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* /usr/local/devel/pglite/cvs/src/backend/executor/nodeAgg.c,v 1.13 1995/08/01 20:19:07 jolly Exp
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "access/heapam.h"
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#include "catalog/pg_aggregate.h"
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#include "executor/executor.h"
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#include "executor/nodeAgg.h"
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#include "optimizer/clauses.h"
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#include "parser/parse_type.h"
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#include "utils/syscache.h"
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/*
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* AggFuncInfo -
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* keeps the transition functions information around
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*/
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typedef struct AggFuncInfo
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{
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Oid xfn1_oid;
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Oid xfn2_oid;
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Oid finalfn_oid;
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FmgrInfo xfn1;
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FmgrInfo xfn2;
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FmgrInfo finalfn;
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} AggFuncInfo;
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static Datum aggGetAttr(TupleTableSlot *tuple, Aggref *aggref, bool *isNull);
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/* ---------------------------------------
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*
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* ExecAgg -
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*
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* ExecAgg receives tuples from its outer subplan and aggregates over
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* the appropriate attribute for each (unique) aggregate in the target
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* list. (The number of tuples to aggregate over depends on whether a
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* GROUP BY clause is present. It might be the number of tuples in a
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* group or all the tuples that satisfy the qualifications.) The value of
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* each aggregate is stored in the expression context for ExecProject to
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* evaluate the result tuple.
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*
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* ExecAgg evaluates each aggregate in the following steps: (initcond1,
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* initcond2 are the initial values and sfunc1, sfunc2, and finalfunc are
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* the transition functions.)
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*
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* value1[i] = initcond1
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* value2[i] = initcond2
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* forall tuples do
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* value1[i] = sfunc1(value1[i], aggregated_value)
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* value2[i] = sfunc2(value2[i])
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* value1[i] = finalfunc(value1[i], value2[i])
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*
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* If initcond1 is NULL then the first non-NULL aggregated_value is
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* assigned directly to value1[i]. sfunc1 isn't applied until value1[i]
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* is non-NULL.
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*
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* If the outer subplan is a Group node, ExecAgg returns as many tuples
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* as there are groups.
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*
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* XXX handling of NULL doesn't work
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*
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* OLD COMMENTS
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*
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* XXX Aggregates should probably have another option: what to do
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* with transfn2 if we hit a null value. "count" (transfn1 = null,
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* transfn2 = increment) will want to have transfn2 called; "avg"
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* (transfn1 = add, transfn2 = increment) will not. -pma 1/3/93
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*
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* ------------------------------------------
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*/
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TupleTableSlot *
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ExecAgg(Agg *node)
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{
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AggState *aggstate;
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EState *estate;
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Plan *outerPlan;
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int aggno,
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numaggs;
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Datum *value1,
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*value2;
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int *noInitValue;
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AggFuncInfo *aggFuncInfo;
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long nTuplesAgged = 0;
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ExprContext *econtext;
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ProjectionInfo *projInfo;
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TupleTableSlot *resultSlot;
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HeapTuple oneTuple;
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List *alist;
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char *nulls;
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bool isDone;
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bool isNull = FALSE,
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isNull1 = FALSE,
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isNull2 = FALSE;
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bool qual_result;
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/* ---------------------
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* get state info from node
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* ---------------------
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*/
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/*
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* We loop retrieving groups until we find one matching
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* node->plan.qual
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*/
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do
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{
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aggstate = node->aggstate;
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if (aggstate->agg_done)
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return NULL;
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estate = node->plan.state;
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econtext = aggstate->csstate.cstate.cs_ExprContext;
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numaggs = length(aggstate->aggs);
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value1 = node->aggstate->csstate.cstate.cs_ExprContext->ecxt_values;
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nulls = node->aggstate->csstate.cstate.cs_ExprContext->ecxt_nulls;
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value2 = (Datum *) palloc(sizeof(Datum) * numaggs);
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MemSet(value2, 0, sizeof(Datum) * numaggs);
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aggFuncInfo = (AggFuncInfo *) palloc(sizeof(AggFuncInfo) * numaggs);
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MemSet(aggFuncInfo, 0, sizeof(AggFuncInfo) * numaggs);
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noInitValue = (int *) palloc(sizeof(int) * numaggs);
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MemSet(noInitValue, 0, sizeof(int) * numaggs);
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outerPlan = outerPlan(node);
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oneTuple = NULL;
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projInfo = aggstate->csstate.cstate.cs_ProjInfo;
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aggno = -1;
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foreach(alist, aggstate->aggs)
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{
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Aggref *aggref = lfirst(alist);
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char *aggname;
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HeapTuple aggTuple;
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Form_pg_aggregate aggp;
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Oid xfn1_oid,
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xfn2_oid,
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finalfn_oid;
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aggref->aggno = ++aggno;
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/* ---------------------
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* find transfer functions of all the aggregates and initialize
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* their initial values
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* ---------------------
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*/
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aggname = aggref->aggname;
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aggTuple = SearchSysCacheTuple(AGGNAME,
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PointerGetDatum(aggname),
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ObjectIdGetDatum(aggref->basetype),
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0, 0);
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if (!HeapTupleIsValid(aggTuple))
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elog(ERROR, "ExecAgg: cache lookup failed for aggregate \"%s\"(%s)",
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aggname,
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typeidTypeName(aggref->basetype));
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aggp = (Form_pg_aggregate) GETSTRUCT(aggTuple);
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xfn1_oid = aggp->aggtransfn1;
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xfn2_oid = aggp->aggtransfn2;
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finalfn_oid = aggp->aggfinalfn;
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if (OidIsValid(finalfn_oid))
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{
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fmgr_info(finalfn_oid, &aggFuncInfo[aggno].finalfn);
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aggFuncInfo[aggno].finalfn_oid = finalfn_oid;
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}
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if (OidIsValid(xfn2_oid))
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{
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fmgr_info(xfn2_oid, &aggFuncInfo[aggno].xfn2);
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aggFuncInfo[aggno].xfn2_oid = xfn2_oid;
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value2[aggno] = (Datum) AggNameGetInitVal((char *) aggname,
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aggp->aggbasetype,
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2,
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&isNull2);
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/* ------------------------------------------
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* If there is a second transition function, its initial
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* value must exist -- as it does not depend on data values,
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* we have no other way of determining an initial value.
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* ------------------------------------------
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*/
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if (isNull2)
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elog(ERROR, "ExecAgg: agginitval2 is null");
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}
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if (OidIsValid(xfn1_oid))
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{
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fmgr_info(xfn1_oid, &aggFuncInfo[aggno].xfn1);
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aggFuncInfo[aggno].xfn1_oid = xfn1_oid;
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value1[aggno] = (Datum) AggNameGetInitVal((char *) aggname,
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aggp->aggbasetype,
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1,
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&isNull1);
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/* ------------------------------------------
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* If the initial value for the first transition function
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* doesn't exist in the pg_aggregate table then we let
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* the first value returned from the outer procNode become
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* the initial value. (This is useful for aggregates like
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* max{} and min{}.)
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* ------------------------------------------
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*/
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if (isNull1)
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{
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noInitValue[aggno] = 1;
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nulls[aggno] = 1;
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}
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}
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}
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/* ----------------
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* for each tuple from the the outer plan, apply all the aggregates
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* ----------------
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*/
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for (;;)
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{
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TupleTableSlot *outerslot;
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isNull = isNull1 = isNull2 = 0;
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outerslot = ExecProcNode(outerPlan, (Plan *) node);
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if (TupIsNull(outerslot))
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{
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/*
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* when the outerplan doesn't return a single tuple,
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* create a dummy heaptuple anyway because we still need
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* to return a valid aggregate value. The value returned
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* will be the initial values of the transition functions
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*/
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if (nTuplesAgged == 0)
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{
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TupleDesc tupType;
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Datum *tupValue;
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char *null_array;
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AttrNumber attnum;
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tupType = aggstate->csstate.css_ScanTupleSlot->ttc_tupleDescriptor;
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tupValue = projInfo->pi_tupValue;
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/* initially, set all the values to NULL */
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null_array = palloc(sizeof(char) * tupType->natts);
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for (attnum = 0; attnum < tupType->natts; attnum++)
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null_array[attnum] = 'n';
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oneTuple = heap_formtuple(tupType, tupValue, null_array);
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pfree(null_array);
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}
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break;
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}
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aggno = -1;
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foreach(alist, aggstate->aggs)
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{
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Aggref *aggref = lfirst(alist);
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AggFuncInfo *aggfns = &aggFuncInfo[++aggno];
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Datum newVal;
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Datum args[2];
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/* Do we really need the special case for Var here? */
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if (IsA(aggref->target, Var))
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{
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newVal = aggGetAttr(outerslot, aggref,
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&isNull);
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}
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else
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{
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econtext->ecxt_scantuple = outerslot;
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newVal = ExecEvalExpr(aggref->target, econtext,
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&isNull, &isDone);
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}
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if (isNull && !aggref->usenulls)
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continue; /* ignore this tuple for this agg */
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if (aggfns->xfn1.fn_addr != NULL)
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{
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if (noInitValue[aggno])
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{
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/*
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* value1 has not been initialized. This is the
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* first non-NULL input value. We use it as the
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* initial value for value1.
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*
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* But we can't just use it straight, we have to make
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* a copy of it since the tuple from which it came
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* will be freed on the next iteration of the
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* scan. This requires finding out how to copy
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* the Datum. We assume the datum is of the agg's
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* basetype, or at least binary compatible with
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* it.
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*/
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Type aggBaseType = typeidType(aggref->basetype);
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int attlen = typeLen(aggBaseType);
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bool byVal = typeByVal(aggBaseType);
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if (byVal)
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value1[aggno] = newVal;
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else
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{
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if (attlen == -1) /* variable length */
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attlen = VARSIZE((struct varlena *) newVal);
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value1[aggno] = (Datum) palloc(attlen);
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memcpy((char *) (value1[aggno]), (char *) newVal,
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attlen);
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}
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noInitValue[aggno] = 0;
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nulls[aggno] = 0;
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}
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else
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{
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/*
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* apply the transition functions.
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*/
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args[0] = value1[aggno];
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args[1] = newVal;
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value1[aggno] = (Datum) fmgr_c(&aggfns->xfn1,
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(FmgrValues *) args, &isNull1);
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Assert(!isNull1);
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}
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}
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if (aggfns->xfn2.fn_addr != NULL)
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{
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args[0] = value2[aggno];
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value2[aggno] = (Datum) fmgr_c(&aggfns->xfn2,
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(FmgrValues *) args, &isNull2);
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Assert(!isNull2);
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}
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}
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/*
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* keep this for the projection (we only need one of these -
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* all the tuples we aggregate over share the same group
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* column)
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*/
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if (!oneTuple)
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oneTuple = heap_copytuple(outerslot->val);
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nTuplesAgged++;
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}
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/* --------------
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* finalize the aggregate (if necessary), and get the resultant value
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* --------------
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*/
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aggno = -1;
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foreach(alist, aggstate->aggs)
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{
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char *args[2];
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AggFuncInfo *aggfns = &aggFuncInfo[++aggno];
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if (noInitValue[aggno])
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{
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/*
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* No values found for this agg; return current state.
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* This seems to fix behavior for avg() aggregate. -tgl
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* 12/96
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*/
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}
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else if (aggfns->finalfn.fn_addr != NULL && nTuplesAgged > 0)
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{
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if (aggfns->finalfn.fn_nargs > 1)
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{
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args[0] = (char *) value1[aggno];
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args[1] = (char *) value2[aggno];
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}
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else if (aggfns->xfn1.fn_addr != NULL)
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args[0] = (char *) value1[aggno];
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else if (aggfns->xfn2.fn_addr != NULL)
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args[0] = (char *) value2[aggno];
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else
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elog(NOTICE, "ExecAgg: no valid transition functions??");
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value1[aggno] = (Datum) fmgr_c(&aggfns->finalfn,
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(FmgrValues *) args, &(nulls[aggno]));
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}
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else if (aggfns->xfn1.fn_addr != NULL)
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{
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/*
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* value in the right place, ignore. (If you remove this
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* case, fix the else part. -ay 2/95)
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*/
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}
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else if (aggfns->xfn2.fn_addr != NULL)
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value1[aggno] = value2[aggno];
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else
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elog(ERROR, "ExecAgg: no valid transition functions??");
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}
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/*
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* whether the aggregation is done depends on whether we are doing
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* aggregation over groups or the entire table
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*/
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if (nodeTag(outerPlan) == T_Group)
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{
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/* aggregation over groups */
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aggstate->agg_done = ((Group *) outerPlan)->grpstate->grp_done;
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}
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else
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aggstate->agg_done = TRUE;
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/* ----------------
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* form a projection tuple, store it in the result tuple
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* slot and return it.
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* ----------------
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*/
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ExecStoreTuple(oneTuple,
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aggstate->csstate.css_ScanTupleSlot,
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InvalidBuffer,
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false);
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econtext->ecxt_scantuple = aggstate->csstate.css_ScanTupleSlot;
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resultSlot = ExecProject(projInfo, &isDone);
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/*
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* As long as the retrieved group does not match the
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* qualifications it is ignored and the next group is fetched
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*/
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if (node->plan.qual != NULL)
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qual_result = ExecQual(node->plan.qual, econtext);
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else
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qual_result = false;
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if (oneTuple)
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pfree(oneTuple);
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}
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while (node->plan.qual != NULL && qual_result != true);
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return resultSlot;
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}
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/* -----------------
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* ExecInitAgg
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*
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* Creates the run-time information for the agg node produced by the
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* planner and initializes its outer subtree
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* -----------------
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*/
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bool
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ExecInitAgg(Agg *node, EState *estate, Plan *parent)
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{
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AggState *aggstate;
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Plan *outerPlan;
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ExprContext *econtext;
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int numaggs;
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/*
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* assign the node's execution state
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*/
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node->plan.state = estate;
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/*
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* create state structure
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*/
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aggstate = makeNode(AggState);
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node->aggstate = aggstate;
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aggstate->agg_done = false;
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/*
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* find aggregates in targetlist and quals
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*/
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aggstate->aggs = nconc(pull_agg_clause((Node *) node->plan.targetlist),
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pull_agg_clause((Node *) node->plan.qual));
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numaggs = length(aggstate->aggs);
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if (numaggs <= 0)
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elog(ERROR, "ExecInitAgg: could not find any aggregate functions");
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/*
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* assign node's base id and create expression context
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*/
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ExecAssignNodeBaseInfo(estate, &aggstate->csstate.cstate, (Plan *) parent);
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ExecAssignExprContext(estate, &aggstate->csstate.cstate);
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#define AGG_NSLOTS 2
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/*
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* tuple table initialization
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*/
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ExecInitScanTupleSlot(estate, &aggstate->csstate);
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ExecInitResultTupleSlot(estate, &aggstate->csstate.cstate);
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econtext = aggstate->csstate.cstate.cs_ExprContext;
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econtext->ecxt_values = (Datum *) palloc(sizeof(Datum) * numaggs);
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MemSet(econtext->ecxt_values, 0, sizeof(Datum) * numaggs);
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econtext->ecxt_nulls = (char *) palloc(sizeof(char) * numaggs);
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MemSet(econtext->ecxt_nulls, 0, sizeof(char) * numaggs);
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/*
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* initializes child nodes
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*/
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outerPlan = outerPlan(node);
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ExecInitNode(outerPlan, estate, (Plan *) node);
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/*
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* Result runs in its own context, but make it use our aggregates fix
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* for 'select sum(2+2)'
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*/
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if (IsA(outerPlan, Result))
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{
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((Result *) outerPlan)->resstate->cstate.cs_ProjInfo->pi_exprContext->ecxt_values =
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econtext->ecxt_values;
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((Result *) outerPlan)->resstate->cstate.cs_ProjInfo->pi_exprContext->ecxt_nulls =
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econtext->ecxt_nulls;
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}
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/* ----------------
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* initialize tuple type.
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|
* ----------------
|
|
*/
|
|
ExecAssignScanTypeFromOuterPlan((Plan *) node, &aggstate->csstate);
|
|
|
|
/*
|
|
* Initialize tuple type for both result and scan. This node does no
|
|
* projection
|
|
*/
|
|
ExecAssignResultTypeFromTL((Plan *) node, &aggstate->csstate.cstate);
|
|
ExecAssignProjectionInfo((Plan *) node, &aggstate->csstate.cstate);
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
int
|
|
ExecCountSlotsAgg(Agg *node)
|
|
{
|
|
return ExecCountSlotsNode(outerPlan(node)) +
|
|
ExecCountSlotsNode(innerPlan(node)) +
|
|
AGG_NSLOTS;
|
|
}
|
|
|
|
/* ------------------------
|
|
* ExecEndAgg(node)
|
|
*
|
|
* -----------------------
|
|
*/
|
|
void
|
|
ExecEndAgg(Agg *node)
|
|
{
|
|
AggState *aggstate;
|
|
Plan *outerPlan;
|
|
|
|
aggstate = node->aggstate;
|
|
|
|
ExecFreeProjectionInfo(&aggstate->csstate.cstate);
|
|
|
|
outerPlan = outerPlan(node);
|
|
ExecEndNode(outerPlan, (Plan *) node);
|
|
|
|
/* clean up tuple table */
|
|
ExecClearTuple(aggstate->csstate.css_ScanTupleSlot);
|
|
}
|
|
|
|
|
|
/*****************************************************************************
|
|
* Support Routines
|
|
*****************************************************************************/
|
|
|
|
/*
|
|
* aggGetAttr -
|
|
* get the attribute (specified in the Var node in agg) to aggregate
|
|
* over from the tuple
|
|
*/
|
|
static Datum
|
|
aggGetAttr(TupleTableSlot *slot,
|
|
Aggref *aggref,
|
|
bool *isNull)
|
|
{
|
|
Datum result;
|
|
AttrNumber attnum;
|
|
HeapTuple heapTuple;
|
|
TupleDesc tuple_type;
|
|
Buffer buffer;
|
|
|
|
/* ----------------
|
|
* extract tuple information from the slot
|
|
* ----------------
|
|
*/
|
|
heapTuple = slot->val;
|
|
tuple_type = slot->ttc_tupleDescriptor;
|
|
buffer = slot->ttc_buffer;
|
|
|
|
attnum = ((Var *) aggref->target)->varattno;
|
|
|
|
/*
|
|
* If the attribute number is invalid, then we are supposed to return
|
|
* the entire tuple, we give back a whole slot so that callers know
|
|
* what the tuple looks like.
|
|
*/
|
|
if (attnum == InvalidAttrNumber)
|
|
{
|
|
TupleTableSlot *tempSlot;
|
|
TupleDesc td;
|
|
HeapTuple tup;
|
|
|
|
tempSlot = makeNode(TupleTableSlot);
|
|
tempSlot->ttc_shouldFree = false;
|
|
tempSlot->ttc_descIsNew = true;
|
|
tempSlot->ttc_tupleDescriptor = (TupleDesc) NULL;
|
|
tempSlot->ttc_buffer = InvalidBuffer;
|
|
tempSlot->ttc_whichplan = -1;
|
|
|
|
tup = heap_copytuple(heapTuple);
|
|
td = CreateTupleDescCopy(slot->ttc_tupleDescriptor);
|
|
|
|
ExecSetSlotDescriptor(tempSlot, td);
|
|
|
|
ExecStoreTuple(tup, tempSlot, InvalidBuffer, true);
|
|
return (Datum) tempSlot;
|
|
}
|
|
|
|
result = heap_getattr(heapTuple, /* tuple containing attribute */
|
|
attnum, /* attribute number of desired
|
|
* attribute */
|
|
tuple_type, /* tuple descriptor of tuple */
|
|
isNull); /* return: is attribute null? */
|
|
|
|
/* ----------------
|
|
* return null if att is null
|
|
* ----------------
|
|
*/
|
|
if (*isNull)
|
|
return (Datum) NULL;
|
|
|
|
return result;
|
|
}
|
|
|
|
void
|
|
ExecReScanAgg(Agg *node, ExprContext *exprCtxt, Plan *parent)
|
|
{
|
|
AggState *aggstate = node->aggstate;
|
|
ExprContext *econtext = aggstate->csstate.cstate.cs_ExprContext;
|
|
|
|
aggstate->agg_done = false;
|
|
MemSet(econtext->ecxt_values, 0, sizeof(Datum) * length(aggstate->aggs));
|
|
MemSet(econtext->ecxt_nulls, 0, sizeof(char) * length(aggstate->aggs));
|
|
|
|
/*
|
|
* if chgParam of subnode is not null then plan will be re-scanned by
|
|
* first ExecProcNode.
|
|
*/
|
|
if (((Plan *) node)->lefttree->chgParam == NULL)
|
|
ExecReScan(((Plan *) node)->lefttree, exprCtxt, (Plan *) node);
|
|
|
|
}
|