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a933ee38bb
maintained for each cache entry. A cache entry will not be freed until the matching ReleaseSysCache call has been executed. This eliminates worries about cache entries getting dropped while still in use. See my posting to pg-hackers of even date for more info.
976 lines
29 KiB
C
976 lines
29 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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* ExecAgg evaluates each aggregate in the following steps:
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*
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* transvalue = initcond
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* foreach input_value do
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* transvalue = transfunc(transvalue, input_value)
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* result = finalfunc(transvalue)
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*
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* If a finalfunc is not supplied then the result is just the ending
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* value of transvalue.
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*
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* If transfunc is marked "strict" in pg_proc and initcond is NULL,
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* then the first non-NULL input_value is assigned directly to transvalue,
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* and transfunc isn't applied until the second non-NULL input_value.
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* The agg's input type and transtype must be the same in this case!
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*
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* If transfunc is marked "strict" then NULL input_values are skipped,
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* keeping the previous transvalue. If transfunc is not strict then it
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* is called for every input tuple and must deal with NULL initcond
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* or NULL input_value for itself.
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*
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* If finalfunc is marked "strict" then it is not called when the
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* ending transvalue is NULL, instead a NULL result is created
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* automatically (this is just the usual handling of strict functions,
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* of course). A non-strict finalfunc can make its own choice of
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* what to return for a NULL ending transvalue.
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*
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*
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* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
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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/nodeAgg.c,v 1.72 2000/11/16 22:30:22 tgl 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 "catalog/pg_operator.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_coerce.h"
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#include "parser/parse_expr.h"
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#include "parser/parse_oper.h"
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#include "parser/parse_type.h"
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#include "utils/lsyscache.h"
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#include "utils/syscache.h"
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#include "utils/tuplesort.h"
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#include "utils/datum.h"
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/*
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* AggStatePerAggData - per-aggregate working state for the Agg scan
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*/
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typedef struct AggStatePerAggData
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{
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/*
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* These values are set up during ExecInitAgg() and do not change
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* thereafter:
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*/
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/* Link to Aggref node this working state is for */
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Aggref *aggref;
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/* Oids of transfer functions */
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Oid transfn_oid;
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Oid finalfn_oid; /* may be InvalidOid */
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/*
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* fmgr lookup data for transfer functions --- only valid when
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* corresponding oid is not InvalidOid. Note in particular that
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* fn_strict flags are kept here.
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*/
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FmgrInfo transfn;
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FmgrInfo finalfn;
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/*
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* Type of input data and Oid of sort operator to use for it; only
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* set/used when aggregate has DISTINCT flag. (These are not used
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* directly by nodeAgg, but must be passed to the Tuplesort object.)
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*/
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Oid inputType;
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Oid sortOperator;
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/*
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* fmgr lookup data for input type's equality operator --- only
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* set/used when aggregate has DISTINCT flag.
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*/
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FmgrInfo equalfn;
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/*
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* initial value from pg_aggregate entry
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*/
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Datum initValue;
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bool initValueIsNull;
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/*
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* We need the len and byval info for the agg's input, result, and
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* transition data types in order to know how to copy/delete values.
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*/
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int16 inputtypeLen,
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resulttypeLen,
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transtypeLen;
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bool inputtypeByVal,
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resulttypeByVal,
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transtypeByVal;
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/*
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* These values are working state that is initialized at the start of
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* an input tuple group and updated for each input tuple.
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*
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* For a simple (non DISTINCT) aggregate, we just feed the input values
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* straight to the transition function. If it's DISTINCT, we pass
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* the input values into a Tuplesort object; then at completion of the
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* input tuple group, we scan the sorted values, eliminate duplicates,
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* and run the transition function on the rest.
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*/
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Tuplesortstate *sortstate; /* sort object, if a DISTINCT agg */
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Datum transValue;
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bool transValueIsNull;
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bool noTransValue; /* true if transValue not set yet */
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/*
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* Note: noTransValue initially has the same value as transValueIsNull,
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* and if true both are cleared to false at the same time. They are
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* not the same though: if transfn later returns a NULL, we want to
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* keep that NULL and not auto-replace it with a later input value.
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* Only the first non-NULL input will be auto-substituted.
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*/
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} AggStatePerAggData;
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static void initialize_aggregate(AggStatePerAgg peraggstate);
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static void advance_transition_function(AggStatePerAgg peraggstate,
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Datum newVal, bool isNull);
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static void process_sorted_aggregate(AggState *aggstate,
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AggStatePerAgg peraggstate);
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static void finalize_aggregate(AggStatePerAgg peraggstate,
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Datum *resultVal, bool *resultIsNull);
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/*
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* Initialize one aggregate for a new set of input values.
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*
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* When called, CurrentMemoryContext should be the per-query context.
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*/
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static void
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initialize_aggregate(AggStatePerAgg peraggstate)
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{
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Aggref *aggref = peraggstate->aggref;
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/*
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* Start a fresh sort operation for each DISTINCT aggregate.
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*/
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if (aggref->aggdistinct)
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{
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/*
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* In case of rescan, maybe there could be an uncompleted sort
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* operation? Clean it up if so.
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*/
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if (peraggstate->sortstate)
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tuplesort_end(peraggstate->sortstate);
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peraggstate->sortstate =
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tuplesort_begin_datum(peraggstate->inputType,
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peraggstate->sortOperator,
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false);
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}
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/*
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* (Re)set transValue to the initial value.
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*
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* Note that when the initial value is pass-by-ref, we just reuse it
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* without copying for each group. Hence, transition function
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* had better not scribble on its input, or it will fail for GROUP BY!
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*/
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peraggstate->transValue = peraggstate->initValue;
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peraggstate->transValueIsNull = peraggstate->initValueIsNull;
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/* ------------------------------------------
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* If the initial value for the transition state doesn't exist in the
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* pg_aggregate table then we will let the first non-NULL value returned
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* from the outer procNode become the initial value. (This is useful for
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* aggregates like max() and min().) The noTransValue flag signals that
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* we still need to do this.
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* ------------------------------------------
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*/
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peraggstate->noTransValue = peraggstate->initValueIsNull;
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}
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/*
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* Given a new input value, advance the transition function of an aggregate.
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*
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* When called, CurrentMemoryContext should be the context we want the
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* transition function result to be delivered into on this cycle.
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*/
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static void
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advance_transition_function(AggStatePerAgg peraggstate,
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Datum newVal, bool isNull)
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{
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FunctionCallInfoData fcinfo;
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if (peraggstate->transfn.fn_strict)
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{
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if (isNull)
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{
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/*
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* For a strict transfn, nothing happens at a NULL input tuple;
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* we just keep the prior transValue. However, if the transtype
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* is pass-by-ref, we have to copy it into the new context
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* because the old one is going to get reset.
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*/
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if (!peraggstate->transValueIsNull)
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peraggstate->transValue = datumCopy(peraggstate->transValue,
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peraggstate->transtypeByVal,
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peraggstate->transtypeLen);
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return;
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}
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if (peraggstate->noTransValue)
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{
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/*
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* transValue has not been initialized. This is the first non-NULL
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* input value. We use it as the initial value for transValue.
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* (We already checked that the agg's input type is binary-
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* compatible with its transtype, so straight copy here is OK.)
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*
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* We had better copy the datum if it is pass-by-ref, since
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* the given pointer may be pointing into a scan tuple that
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* will be freed on the next iteration of the scan.
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*/
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peraggstate->transValue = datumCopy(newVal,
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peraggstate->transtypeByVal,
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peraggstate->transtypeLen);
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peraggstate->transValueIsNull = false;
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peraggstate->noTransValue = false;
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return;
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}
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if (peraggstate->transValueIsNull)
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{
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/*
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* Don't call a strict function with NULL inputs. Note it is
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* possible to get here despite the above tests, if the transfn
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* is strict *and* returned a NULL on a prior cycle. If that
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* happens we will propagate the NULL all the way to the end.
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*/
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return;
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}
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}
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/* OK to call the transition function */
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MemSet(&fcinfo, 0, sizeof(fcinfo));
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fcinfo.flinfo = &peraggstate->transfn;
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fcinfo.nargs = 2;
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fcinfo.arg[0] = peraggstate->transValue;
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fcinfo.argnull[0] = peraggstate->transValueIsNull;
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fcinfo.arg[1] = newVal;
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fcinfo.argnull[1] = isNull;
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newVal = FunctionCallInvoke(&fcinfo);
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/*
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* If the transition function was uncooperative, it may have
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* given us a pass-by-ref result that points at the scan tuple
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* or the prior-cycle working memory. Copy it into the active
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* context if it doesn't look right.
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*/
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if (!peraggstate->transtypeByVal && !fcinfo.isnull &&
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! MemoryContextContains(CurrentMemoryContext,
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DatumGetPointer(newVal)))
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newVal = datumCopy(newVal,
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peraggstate->transtypeByVal,
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peraggstate->transtypeLen);
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peraggstate->transValue = newVal;
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peraggstate->transValueIsNull = fcinfo.isnull;
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}
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/*
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* Run the transition function for a DISTINCT aggregate. This is called
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* after we have completed entering all the input values into the sort
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* object. We complete the sort, read out the values in sorted order,
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* and run the transition function on each non-duplicate value.
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*
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* When called, CurrentMemoryContext should be the per-query context.
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*/
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static void
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process_sorted_aggregate(AggState *aggstate,
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AggStatePerAgg peraggstate)
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{
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Datum oldVal = (Datum) 0;
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bool haveOldVal = false;
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MemoryContext oldContext;
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Datum newVal;
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bool isNull;
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tuplesort_performsort(peraggstate->sortstate);
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/*
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* Note: if input type is pass-by-ref, the datums returned by the sort
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* are freshly palloc'd in the per-query context, so we must be careful
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* to pfree them when they are no longer needed.
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*/
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while (tuplesort_getdatum(peraggstate->sortstate, true,
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&newVal, &isNull))
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{
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/*
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* DISTINCT always suppresses nulls, per SQL spec, regardless of
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* the transition function's strictness.
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*/
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if (isNull)
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continue;
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/*
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* Clear and select the current working context for evaluation of
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* the equality function and transition function.
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*/
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MemoryContextReset(aggstate->agg_cxt[aggstate->which_cxt]);
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oldContext =
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MemoryContextSwitchTo(aggstate->agg_cxt[aggstate->which_cxt]);
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if (haveOldVal &&
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DatumGetBool(FunctionCall2(&peraggstate->equalfn,
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oldVal, newVal)))
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{
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/* equal to prior, so forget this one */
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if (!peraggstate->inputtypeByVal)
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pfree(DatumGetPointer(newVal));
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/*
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* note we do NOT flip contexts in this case, so no need to
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* copy prior transValue to other context.
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*/
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}
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else
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{
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advance_transition_function(peraggstate, newVal, false);
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/*
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* Make the other context current so that this transition
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* result is preserved.
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*/
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aggstate->which_cxt = 1 - aggstate->which_cxt;
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/* forget the old value, if any */
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if (haveOldVal && !peraggstate->inputtypeByVal)
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pfree(DatumGetPointer(oldVal));
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oldVal = newVal;
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haveOldVal = true;
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}
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MemoryContextSwitchTo(oldContext);
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}
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if (haveOldVal && !peraggstate->inputtypeByVal)
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pfree(DatumGetPointer(oldVal));
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tuplesort_end(peraggstate->sortstate);
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peraggstate->sortstate = NULL;
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}
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/*
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* Compute the final value of one aggregate.
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*
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* When called, CurrentMemoryContext should be the context where we want
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* final values delivered (ie, the per-output-tuple expression context).
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*/
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static void
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finalize_aggregate(AggStatePerAgg peraggstate,
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Datum *resultVal, bool *resultIsNull)
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{
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/*
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* Apply the agg's finalfn if one is provided, else return transValue.
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*/
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if (OidIsValid(peraggstate->finalfn_oid))
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{
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FunctionCallInfoData fcinfo;
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MemSet(&fcinfo, 0, sizeof(fcinfo));
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fcinfo.flinfo = &peraggstate->finalfn;
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fcinfo.nargs = 1;
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fcinfo.arg[0] = peraggstate->transValue;
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fcinfo.argnull[0] = peraggstate->transValueIsNull;
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if (fcinfo.flinfo->fn_strict && peraggstate->transValueIsNull)
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{
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/* don't call a strict function with NULL inputs */
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*resultVal = (Datum) 0;
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*resultIsNull = true;
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}
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else
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{
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*resultVal = FunctionCallInvoke(&fcinfo);
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*resultIsNull = fcinfo.isnull;
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}
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}
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else
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{
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*resultVal = peraggstate->transValue;
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*resultIsNull = peraggstate->transValueIsNull;
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}
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/*
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* If result is pass-by-ref, make sure it is in the right context.
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*/
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if (!peraggstate->resulttypeByVal && ! *resultIsNull &&
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! MemoryContextContains(CurrentMemoryContext,
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DatumGetPointer(*resultVal)))
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*resultVal = datumCopy(*resultVal,
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peraggstate->resulttypeByVal,
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peraggstate->resulttypeLen);
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}
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|
|
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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 aggregate function use (Aggref
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* node) appearing in the targetlist or qual of the node. The number
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* of tuples to aggregate over depends on whether a GROUP BY clause is
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* present. We can produce an aggregate result row per group, or just
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* one for the whole query. The value of each aggregate is stored in
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* the expression context to be used when ExecProject evaluates the
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* result tuple.
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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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* ------------------------------------------
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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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ExprContext *econtext;
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ProjectionInfo *projInfo;
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Datum *aggvalues;
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bool *aggnulls;
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AggStatePerAgg peragg;
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MemoryContext oldContext;
|
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TupleTableSlot *resultSlot;
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HeapTuple inputTuple;
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int aggno;
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bool isNull;
|
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|
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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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aggstate = node->aggstate;
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estate = node->plan.state;
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outerPlan = outerPlan(node);
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econtext = aggstate->csstate.cstate.cs_ExprContext;
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aggvalues = econtext->ecxt_aggvalues;
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aggnulls = econtext->ecxt_aggnulls;
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projInfo = aggstate->csstate.cstate.cs_ProjInfo;
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peragg = aggstate->peragg;
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|
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/*
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* We loop retrieving groups until we find one matching node->plan.qual
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*/
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do
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{
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if (aggstate->agg_done)
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return NULL;
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|
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/*
|
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* Clear the per-output-tuple context for each group
|
|
*/
|
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MemoryContextReset(aggstate->tup_cxt);
|
|
|
|
/*
|
|
* Initialize working state for a new input tuple group
|
|
*/
|
|
for (aggno = 0; aggno < aggstate->numaggs; aggno++)
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{
|
|
AggStatePerAgg peraggstate = &peragg[aggno];
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|
|
initialize_aggregate(peraggstate);
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}
|
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|
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inputTuple = NULL; /* no saved input tuple yet */
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|
|
/* ----------------
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* for each tuple from the outer plan, update all the aggregates
|
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* ----------------
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*/
|
|
for (;;)
|
|
{
|
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TupleTableSlot *outerslot;
|
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|
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outerslot = ExecProcNode(outerPlan, (Plan *) node);
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if (TupIsNull(outerslot))
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break;
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econtext->ecxt_scantuple = outerslot;
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|
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/*
|
|
* Clear and select the current working context for evaluation
|
|
* of the input expressions and transition functions at this
|
|
* input tuple.
|
|
*/
|
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econtext->ecxt_per_tuple_memory =
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aggstate->agg_cxt[aggstate->which_cxt];
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ResetExprContext(econtext);
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oldContext =
|
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MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
|
|
|
|
for (aggno = 0; aggno < aggstate->numaggs; aggno++)
|
|
{
|
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AggStatePerAgg peraggstate = &peragg[aggno];
|
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Aggref *aggref = peraggstate->aggref;
|
|
Datum newVal;
|
|
|
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newVal = ExecEvalExpr(aggref->target, econtext,
|
|
&isNull, NULL);
|
|
|
|
if (aggref->aggdistinct)
|
|
{
|
|
/* in DISTINCT mode, we may ignore nulls */
|
|
if (isNull)
|
|
continue;
|
|
/* putdatum has to be called in per-query context */
|
|
MemoryContextSwitchTo(oldContext);
|
|
tuplesort_putdatum(peraggstate->sortstate,
|
|
newVal, isNull);
|
|
MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
|
|
}
|
|
else
|
|
{
|
|
advance_transition_function(peraggstate,
|
|
newVal, isNull);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Make the other context current so that these transition
|
|
* results are preserved.
|
|
*/
|
|
aggstate->which_cxt = 1 - aggstate->which_cxt;
|
|
|
|
MemoryContextSwitchTo(oldContext);
|
|
|
|
/*
|
|
* Keep a copy of the first input tuple for the projection.
|
|
* (We only need one since only the GROUP BY columns in it can
|
|
* be referenced, and these will be the same for all tuples
|
|
* aggregated over.)
|
|
*/
|
|
if (!inputTuple)
|
|
inputTuple = heap_copytuple(outerslot->val);
|
|
}
|
|
|
|
/*
|
|
* Done scanning input tuple group. Finalize each aggregate
|
|
* calculation, and stash results in the per-output-tuple context.
|
|
*
|
|
* This is a bit tricky when there are both DISTINCT and plain
|
|
* aggregates: we must first finalize all the plain aggs and then all
|
|
* the DISTINCT ones. This is needed because the last transition
|
|
* values for the plain aggs are stored in the not-current working
|
|
* context, and we have to evaluate those aggs (and stash the results
|
|
* in the output tup_cxt!) before we start flipping contexts again
|
|
* in process_sorted_aggregate.
|
|
*/
|
|
oldContext = MemoryContextSwitchTo(aggstate->tup_cxt);
|
|
for (aggno = 0; aggno < aggstate->numaggs; aggno++)
|
|
{
|
|
AggStatePerAgg peraggstate = &peragg[aggno];
|
|
|
|
if (! peraggstate->aggref->aggdistinct)
|
|
finalize_aggregate(peraggstate,
|
|
&aggvalues[aggno], &aggnulls[aggno]);
|
|
}
|
|
MemoryContextSwitchTo(oldContext);
|
|
for (aggno = 0; aggno < aggstate->numaggs; aggno++)
|
|
{
|
|
AggStatePerAgg peraggstate = &peragg[aggno];
|
|
|
|
if (peraggstate->aggref->aggdistinct)
|
|
{
|
|
process_sorted_aggregate(aggstate, peraggstate);
|
|
oldContext = MemoryContextSwitchTo(aggstate->tup_cxt);
|
|
finalize_aggregate(peraggstate,
|
|
&aggvalues[aggno], &aggnulls[aggno]);
|
|
MemoryContextSwitchTo(oldContext);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If the outerPlan is a Group node, we will reach here after each
|
|
* group. We are not done unless the Group node is done (a little
|
|
* ugliness here while we reach into the Group's state to find
|
|
* out). Furthermore, when grouping we return nothing at all
|
|
* unless we had some input tuple(s). By the nature of Group,
|
|
* there are no empty groups, so if we get here with no input the
|
|
* whole scan is empty.
|
|
*
|
|
* If the outerPlan isn't a Group, we are done when we get here, and
|
|
* we will emit a (single) tuple even if there were no input
|
|
* tuples.
|
|
*/
|
|
if (IsA(outerPlan, Group))
|
|
{
|
|
/* aggregation over groups */
|
|
aggstate->agg_done = ((Group *) outerPlan)->grpstate->grp_done;
|
|
/* check for no groups */
|
|
if (inputTuple == NULL)
|
|
return NULL;
|
|
}
|
|
else
|
|
{
|
|
aggstate->agg_done = true;
|
|
|
|
/*
|
|
* If inputtuple==NULL (ie, the outerPlan didn't return
|
|
* anything), create a dummy all-nulls input tuple for use by
|
|
* ExecProject. 99.44% of the time this is a waste of cycles,
|
|
* because ordinarily the projected output tuple's targetlist
|
|
* cannot contain any direct (non-aggregated) references to
|
|
* input columns, so the dummy tuple will not be referenced.
|
|
* However there are special cases where this isn't so --- in
|
|
* particular an UPDATE involving an aggregate will have a
|
|
* targetlist reference to ctid. We need to return a null for
|
|
* ctid in that situation, not coredump.
|
|
*
|
|
* The values returned for the aggregates will be the initial
|
|
* values of the transition functions.
|
|
*/
|
|
if (inputTuple == NULL)
|
|
{
|
|
TupleDesc tupType;
|
|
Datum *tupValue;
|
|
char *null_array;
|
|
AttrNumber attnum;
|
|
|
|
tupType = aggstate->csstate.css_ScanTupleSlot->ttc_tupleDescriptor;
|
|
tupValue = projInfo->pi_tupValue;
|
|
/* watch out for null input tuples, though... */
|
|
if (tupType && tupValue)
|
|
{
|
|
null_array = (char *) palloc(sizeof(char) * tupType->natts);
|
|
for (attnum = 0; attnum < tupType->natts; attnum++)
|
|
null_array[attnum] = 'n';
|
|
inputTuple = heap_formtuple(tupType, tupValue, null_array);
|
|
pfree(null_array);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Store the representative input tuple in the tuple table slot
|
|
* reserved for it. The tuple will be deleted when it is cleared
|
|
* from the slot.
|
|
*/
|
|
ExecStoreTuple(inputTuple,
|
|
aggstate->csstate.css_ScanTupleSlot,
|
|
InvalidBuffer,
|
|
true);
|
|
econtext->ecxt_scantuple = aggstate->csstate.css_ScanTupleSlot;
|
|
|
|
/*
|
|
* Do projection and qual check in the per-output-tuple context.
|
|
*/
|
|
econtext->ecxt_per_tuple_memory = aggstate->tup_cxt;
|
|
|
|
/*
|
|
* Form a projection tuple using the aggregate results and the
|
|
* representative input tuple. Store it in the result tuple slot.
|
|
* Note we do not support aggregates returning sets ...
|
|
*/
|
|
resultSlot = ExecProject(projInfo, NULL);
|
|
|
|
/*
|
|
* If the completed tuple does not match the qualifications, it is
|
|
* ignored and we loop back to try to process another group.
|
|
* Otherwise, return the tuple.
|
|
*/
|
|
}
|
|
while (!ExecQual(node->plan.qual, econtext, false));
|
|
|
|
return resultSlot;
|
|
}
|
|
|
|
/* -----------------
|
|
* ExecInitAgg
|
|
*
|
|
* Creates the run-time information for the agg node produced by the
|
|
* planner and initializes its outer subtree
|
|
* -----------------
|
|
*/
|
|
bool
|
|
ExecInitAgg(Agg *node, EState *estate, Plan *parent)
|
|
{
|
|
AggState *aggstate;
|
|
AggStatePerAgg peragg;
|
|
Plan *outerPlan;
|
|
ExprContext *econtext;
|
|
int numaggs,
|
|
aggno;
|
|
List *alist;
|
|
|
|
/*
|
|
* assign the node's execution state
|
|
*/
|
|
node->plan.state = estate;
|
|
|
|
/*
|
|
* create state structure
|
|
*/
|
|
aggstate = makeNode(AggState);
|
|
node->aggstate = aggstate;
|
|
aggstate->agg_done = false;
|
|
|
|
/*
|
|
* find aggregates in targetlist and quals
|
|
*
|
|
* Note: pull_agg_clauses also checks that no aggs contain other agg
|
|
* calls in their arguments. This would make no sense under SQL
|
|
* semantics anyway (and it's forbidden by the spec). Because that is
|
|
* true, we don't need to worry about evaluating the aggs in any
|
|
* particular order.
|
|
*/
|
|
aggstate->aggs = nconc(pull_agg_clause((Node *) node->plan.targetlist),
|
|
pull_agg_clause((Node *) node->plan.qual));
|
|
aggstate->numaggs = numaggs = length(aggstate->aggs);
|
|
if (numaggs <= 0)
|
|
{
|
|
|
|
/*
|
|
* This used to be treated as an error, but we can't do that
|
|
* anymore because constant-expression simplification could
|
|
* optimize away all of the Aggrefs in the targetlist and qual.
|
|
* So, just make a debug note, and force numaggs positive so that
|
|
* palloc()s below don't choke.
|
|
*/
|
|
elog(DEBUG, "ExecInitAgg: could not find any aggregate functions");
|
|
numaggs = 1;
|
|
}
|
|
|
|
/*
|
|
* Create expression context
|
|
*/
|
|
ExecAssignExprContext(estate, &aggstate->csstate.cstate);
|
|
|
|
/*
|
|
* We actually need three separate expression memory contexts: one
|
|
* for calculating per-output-tuple values (ie, the finished aggregate
|
|
* results), and two that we ping-pong between for per-input-tuple
|
|
* evaluation of input expressions and transition functions. The
|
|
* context made by ExecAssignExprContext() is used as the output context.
|
|
*/
|
|
aggstate->tup_cxt =
|
|
aggstate->csstate.cstate.cs_ExprContext->ecxt_per_tuple_memory;
|
|
aggstate->agg_cxt[0] =
|
|
AllocSetContextCreate(CurrentMemoryContext,
|
|
"AggExprContext1",
|
|
ALLOCSET_DEFAULT_MINSIZE,
|
|
ALLOCSET_DEFAULT_INITSIZE,
|
|
ALLOCSET_DEFAULT_MAXSIZE);
|
|
aggstate->agg_cxt[1] =
|
|
AllocSetContextCreate(CurrentMemoryContext,
|
|
"AggExprContext2",
|
|
ALLOCSET_DEFAULT_MINSIZE,
|
|
ALLOCSET_DEFAULT_INITSIZE,
|
|
ALLOCSET_DEFAULT_MAXSIZE);
|
|
aggstate->which_cxt = 0;
|
|
|
|
#define AGG_NSLOTS 2
|
|
|
|
/*
|
|
* tuple table initialization
|
|
*/
|
|
ExecInitScanTupleSlot(estate, &aggstate->csstate);
|
|
ExecInitResultTupleSlot(estate, &aggstate->csstate.cstate);
|
|
|
|
/*
|
|
* Set up aggregate-result storage in the expr context, and also
|
|
* allocate my private per-agg working storage
|
|
*/
|
|
econtext = aggstate->csstate.cstate.cs_ExprContext;
|
|
econtext->ecxt_aggvalues = (Datum *) palloc(sizeof(Datum) * numaggs);
|
|
MemSet(econtext->ecxt_aggvalues, 0, sizeof(Datum) * numaggs);
|
|
econtext->ecxt_aggnulls = (bool *) palloc(sizeof(bool) * numaggs);
|
|
MemSet(econtext->ecxt_aggnulls, 0, sizeof(bool) * numaggs);
|
|
|
|
peragg = (AggStatePerAgg) palloc(sizeof(AggStatePerAggData) * numaggs);
|
|
MemSet(peragg, 0, sizeof(AggStatePerAggData) * numaggs);
|
|
aggstate->peragg = peragg;
|
|
|
|
/*
|
|
* initialize child nodes
|
|
*/
|
|
outerPlan = outerPlan(node);
|
|
ExecInitNode(outerPlan, estate, (Plan *) node);
|
|
|
|
/* ----------------
|
|
* initialize source tuple type.
|
|
* ----------------
|
|
*/
|
|
ExecAssignScanTypeFromOuterPlan((Plan *) node, &aggstate->csstate);
|
|
|
|
/*
|
|
* Initialize result tuple type and projection info.
|
|
*/
|
|
ExecAssignResultTypeFromTL((Plan *) node, &aggstate->csstate.cstate);
|
|
ExecAssignProjectionInfo((Plan *) node, &aggstate->csstate.cstate);
|
|
|
|
/*
|
|
* Perform lookups of aggregate function info, and initialize the
|
|
* unchanging fields of the per-agg data
|
|
*/
|
|
aggno = -1;
|
|
foreach(alist, aggstate->aggs)
|
|
{
|
|
Aggref *aggref = (Aggref *) lfirst(alist);
|
|
AggStatePerAgg peraggstate = &peragg[++aggno];
|
|
char *aggname = aggref->aggname;
|
|
HeapTuple aggTuple;
|
|
Form_pg_aggregate aggform;
|
|
Oid transfn_oid,
|
|
finalfn_oid;
|
|
|
|
/* Mark Aggref node with its associated index in the result array */
|
|
aggref->aggno = aggno;
|
|
|
|
/* Fill in the peraggstate data */
|
|
peraggstate->aggref = aggref;
|
|
|
|
aggTuple = SearchSysCache(AGGNAME,
|
|
PointerGetDatum(aggname),
|
|
ObjectIdGetDatum(aggref->basetype),
|
|
0, 0);
|
|
if (!HeapTupleIsValid(aggTuple))
|
|
elog(ERROR, "ExecAgg: cache lookup failed for aggregate %s(%s)",
|
|
aggname,
|
|
aggref->basetype ?
|
|
typeidTypeName(aggref->basetype) : (char *) "");
|
|
aggform = (Form_pg_aggregate) GETSTRUCT(aggTuple);
|
|
|
|
get_typlenbyval(aggform->aggfinaltype,
|
|
&peraggstate->resulttypeLen,
|
|
&peraggstate->resulttypeByVal);
|
|
get_typlenbyval(aggform->aggtranstype,
|
|
&peraggstate->transtypeLen,
|
|
&peraggstate->transtypeByVal);
|
|
|
|
peraggstate->initValue =
|
|
AggNameGetInitVal(aggname,
|
|
aggform->aggbasetype,
|
|
&peraggstate->initValueIsNull);
|
|
|
|
peraggstate->transfn_oid = transfn_oid = aggform->aggtransfn;
|
|
peraggstate->finalfn_oid = finalfn_oid = aggform->aggfinalfn;
|
|
|
|
fmgr_info(transfn_oid, &peraggstate->transfn);
|
|
if (OidIsValid(finalfn_oid))
|
|
fmgr_info(finalfn_oid, &peraggstate->finalfn);
|
|
|
|
/*
|
|
* If the transfn is strict and the initval is NULL, make sure
|
|
* input type and transtype are the same (or at least binary-
|
|
* compatible), so that it's OK to use the first input value
|
|
* as the initial transValue. This should have been checked at
|
|
* agg definition time, but just in case...
|
|
*/
|
|
if (peraggstate->transfn.fn_strict && peraggstate->initValueIsNull)
|
|
{
|
|
/*
|
|
* Note: use the type from the input expression here,
|
|
* not aggform->aggbasetype, because the latter might be 0.
|
|
* (Consider COUNT(*).)
|
|
*/
|
|
Oid inputType = exprType(aggref->target);
|
|
|
|
if (inputType != aggform->aggtranstype &&
|
|
! IS_BINARY_COMPATIBLE(inputType, aggform->aggtranstype))
|
|
elog(ERROR, "Aggregate %s needs to have compatible input type and transition type",
|
|
aggname);
|
|
}
|
|
|
|
if (aggref->aggdistinct)
|
|
{
|
|
/*
|
|
* Note: use the type from the input expression here,
|
|
* not aggform->aggbasetype, because the latter might be 0.
|
|
* (Consider COUNT(*).)
|
|
*/
|
|
Oid inputType = exprType(aggref->target);
|
|
Operator eq_operator;
|
|
Form_pg_operator pgopform;
|
|
|
|
peraggstate->inputType = inputType;
|
|
get_typlenbyval(inputType,
|
|
&peraggstate->inputtypeLen,
|
|
&peraggstate->inputtypeByVal);
|
|
|
|
eq_operator = oper("=", inputType, inputType, true);
|
|
if (!HeapTupleIsValid(eq_operator))
|
|
elog(ERROR, "Unable to identify an equality operator for type '%s'",
|
|
typeidTypeName(inputType));
|
|
pgopform = (Form_pg_operator) GETSTRUCT(eq_operator);
|
|
fmgr_info(pgopform->oprcode, &(peraggstate->equalfn));
|
|
ReleaseSysCache(eq_operator);
|
|
peraggstate->sortOperator = any_ordering_op(inputType);
|
|
peraggstate->sortstate = NULL;
|
|
}
|
|
|
|
ReleaseSysCache(aggTuple);
|
|
}
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
int
|
|
ExecCountSlotsAgg(Agg *node)
|
|
{
|
|
return ExecCountSlotsNode(outerPlan(node)) +
|
|
ExecCountSlotsNode(innerPlan(node)) +
|
|
AGG_NSLOTS;
|
|
}
|
|
|
|
void
|
|
ExecEndAgg(Agg *node)
|
|
{
|
|
AggState *aggstate = node->aggstate;
|
|
Plan *outerPlan;
|
|
|
|
ExecFreeProjectionInfo(&aggstate->csstate.cstate);
|
|
/*
|
|
* Make sure ExecFreeExprContext() frees the right expr context...
|
|
*/
|
|
aggstate->csstate.cstate.cs_ExprContext->ecxt_per_tuple_memory =
|
|
aggstate->tup_cxt;
|
|
ExecFreeExprContext(&aggstate->csstate.cstate);
|
|
/*
|
|
* ... and I free the others.
|
|
*/
|
|
MemoryContextDelete(aggstate->agg_cxt[0]);
|
|
MemoryContextDelete(aggstate->agg_cxt[1]);
|
|
|
|
outerPlan = outerPlan(node);
|
|
ExecEndNode(outerPlan, (Plan *) node);
|
|
|
|
/* clean up tuple table */
|
|
ExecClearTuple(aggstate->csstate.css_ScanTupleSlot);
|
|
}
|
|
|
|
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_aggvalues, 0, sizeof(Datum) * aggstate->numaggs);
|
|
MemSet(econtext->ecxt_aggnulls, 0, sizeof(bool) * aggstate->numaggs);
|
|
|
|
/*
|
|
* 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);
|
|
}
|