06c8f2afcf
Offering: openGaussDev More detail: deep copy procedure arg value Match-id-dda612d112a2a69b554912340314383a39e71a7c
2004 lines
75 KiB
C++
2004 lines
75 KiB
C++
/* -------------------------------------------------------------------------
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*
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* nodeWindowAgg.cpp
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* routines to handle WindowAgg nodes.
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*
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* A WindowAgg node evaluates "window functions" across suitable partitions
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* of the input tuple set. Any one WindowAgg works for just a single window
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* specification, though it can evaluate multiple window functions sharing
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* identical window specifications. The input tuples are required to be
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* delivered in sorted order, with the PARTITION BY columns (if any) as
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* major sort keys and the ORDER BY columns (if any) as minor sort keys.
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* (The planner generates a stack of WindowAggs with intervening Sort nodes
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* as needed, if a query involves more than one window specification.)
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*
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* Since window functions can require access to any or all of the rows in
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* the current partition, we accumulate rows of the partition into a
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* tuplestore. The window functions are called using the WindowObject API
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* so that they can access those rows as needed.
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*
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* We also support using plain aggregate functions as window functions.
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* For these, the regular Agg-node environment is emulated for each partition.
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* As required by the SQL spec, the output represents the value of the
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* aggregate function over all rows in the current row's window frame.
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*
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* Portions Copyright (c) 2020 Huawei Technologies Co.,Ltd.
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* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* IDENTIFICATION
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* src/gausskernel/runtime/executor/nodeWindowAgg.cpp
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*
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* -------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "knl/knl_variable.h"
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#include "catalog/pg_aggregate.h"
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#include "catalog/pg_proc.h"
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#include "catalog/pg_type.h"
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#include "executor/executor.h"
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#include "executor/node/nodeWindowAgg.h"
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#include "miscadmin.h"
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#include "nodes/nodeFuncs.h"
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#include "optimizer/clauses.h"
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#include "parser/parse_agg.h"
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#include "parser/parse_coerce.h"
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#include "utils/acl.h"
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#include "utils/builtins.h"
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#include "utils/datum.h"
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#include "utils/lsyscache.h"
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#include "utils/memutils.h"
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#include "utils/syscache.h"
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#include "windowapi.h"
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static void initialize_windowaggregate(
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WindowAggState* winstate, WindowStatePerFunc perfuncstate, WindowStatePerAgg peraggstate);
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static void advance_windowaggregate(
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WindowAggState* winstate, WindowStatePerFunc perfuncstate, WindowStatePerAgg peraggstate);
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static void finalize_windowaggregate(WindowAggState* winstate, WindowStatePerFunc perfuncstate,
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WindowStatePerAgg peraggstate, Datum* result, bool* is_null);
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static void eval_windowaggregates(WindowAggState* winstate);
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static void eval_windowfunction(WindowAggState* winstate, WindowStatePerFunc perfuncstate, Datum* result, bool* is_null);
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static void begin_partition(WindowAggState* winstate);
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static void spool_tuples(WindowAggState* winstate, int64 pos);
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static void release_partition(WindowAggState* winstate);
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static bool row_is_in_frame(WindowAggState* winstate, int64 pos, TupleTableSlot* slot);
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static void update_frameheadpos(WindowObject winobj, TupleTableSlot* slot);
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static void update_frametailpos(WindowObject winobj, TupleTableSlot* slot);
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WindowStatePerAggData* initialize_peragg(WindowAggState* winstate, WindowFunc* wfunc, WindowStatePerAgg peraggstate);
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static Datum get_agg_init_val(Datum text_init_val, Oid transtype);
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static bool are_peers(WindowAggState* winstate, TupleTableSlot* slot1, TupleTableSlot* slot2);
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static bool window_gettupleslot(WindowObject winobj, int64 pos, TupleTableSlot* slot);
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/*
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* initialize_windowaggregate
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* parallel to initialize_aggregates in nodeAgg.c
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*/
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static void initialize_windowaggregate(
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WindowAggState* winstate, WindowStatePerFunc perfuncstate, WindowStatePerAgg peraggstate)
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{
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MemoryContext old_context;
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if (peraggstate->initValueIsNull)
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peraggstate->transValue = peraggstate->initValue;
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else {
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old_context = MemoryContextSwitchTo(winstate->aggcontext);
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peraggstate->transValue =
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datumCopy(peraggstate->initValue, peraggstate->transtypeByVal, peraggstate->transtypeLen);
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MemoryContextSwitchTo(old_context);
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}
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peraggstate->transValueIsNull = peraggstate->initValueIsNull;
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peraggstate->noTransValue = peraggstate->initValueIsNull;
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peraggstate->resultValueIsNull = true;
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}
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/*
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* advance_windowaggregate
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* parallel to advance_aggregates in nodeAgg.c
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*/
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static void advance_windowaggregate(
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WindowAggState* winstate, WindowStatePerFunc perfuncstate, WindowStatePerAgg peraggstate)
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{
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WindowFuncExprState* wfuncstate = perfuncstate->wfuncstate;
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int num_arguments = perfuncstate->numArguments;
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FunctionCallInfoData fcinfodata;
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FunctionCallInfo fcinfo = &fcinfodata;
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Datum new_val;
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ListCell* arg = NULL;
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int i;
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MemoryContext old_context;
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ExprContext* econtext = winstate->tmpcontext;
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old_context = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
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/* init the number of arguments to a function. */
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InitFunctionCallInfoArgs(*fcinfo, num_arguments + 1, 1);
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/* We start from 1, since the 0th arg will be the transition value */
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i = 1;
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foreach (arg, wfuncstate->args) {
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ExprState* arg_state = (ExprState*)lfirst(arg);
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fcinfo->arg[i] = ExecEvalExpr(arg_state, econtext, &fcinfo->argnull[i], NULL);
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fcinfo->argTypes[i] = arg_state->resultType;
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i++;
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}
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if (peraggstate->transfn.fn_strict) {
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/*
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* For a strict transfn, nothing happens when there's a NULL input; we
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* just keep the prior transValue.
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*/
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for (i = 1; i <= num_arguments; i++) {
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if (fcinfo->argnull[i]) {
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MemoryContextSwitchTo(old_context);
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return;
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}
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}
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if (peraggstate->noTransValue) {
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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. (We
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* already checked that the agg's input type is binary-compatible
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* with its transtype, so straight copy here is OK.)
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*
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* We must copy the datum into aggcontext if it is pass-by-ref. We
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* do not need to pfree the old transValue, since it's NULL.
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*/
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MemoryContextSwitchTo(winstate->aggcontext);
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peraggstate->transValue = datumCopy(fcinfo->arg[1], peraggstate->transtypeByVal, peraggstate->transtypeLen);
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peraggstate->transValueIsNull = false;
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peraggstate->noTransValue = false;
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MemoryContextSwitchTo(old_context);
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return;
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}
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if (peraggstate->transValueIsNull) {
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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 is
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* strict *and* returned a NULL on a prior cycle. If that happens
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* we will propagate the NULL all the way to the end.
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*/
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MemoryContextSwitchTo(old_context);
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return;
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}
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}
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/*
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* OK to call the transition function
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*/
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InitFunctionCallInfoData(
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*fcinfo, &(peraggstate->transfn), num_arguments + 1, perfuncstate->winCollation, (Node*)winstate, NULL);
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fcinfo->arg[0] = peraggstate->transValue;
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fcinfo->argnull[0] = peraggstate->transValueIsNull;
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fcinfo->argTypes[0] = InvalidOid;
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new_val = FunctionCallInvoke(fcinfo);
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/*
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* If pass-by-ref datatype, must copy the new value into aggcontext and
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* pfree the prior transValue. But if transfn returned a pointer to its
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* first input, we don't need to do anything.
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*/
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if (!peraggstate->transtypeByVal && DatumGetPointer(new_val) != DatumGetPointer(peraggstate->transValue)) {
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if (!fcinfo->isnull) {
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MemoryContextSwitchTo(winstate->aggcontext);
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new_val = datumCopy(new_val, peraggstate->transtypeByVal, peraggstate->transtypeLen);
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}
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if (!peraggstate->transValueIsNull)
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pfree(DatumGetPointer(peraggstate->transValue));
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}
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MemoryContextSwitchTo(old_context);
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peraggstate->transValue = new_val;
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peraggstate->transValueIsNull = fcinfo->isnull;
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}
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/*
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* finalize_windowaggregate
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* parallel to finalize_aggregate in nodeAgg.c
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*/
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static void finalize_windowaggregate(WindowAggState* winstate, WindowStatePerFunc perfuncstate,
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WindowStatePerAgg peraggstate, Datum* result, bool* is_null)
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{
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MemoryContext old_context;
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old_context = MemoryContextSwitchTo(winstate->ss.ps.ps_ExprContext->ecxt_per_tuple_memory);
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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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FunctionCallInfoData fcinfo;
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InitFunctionCallInfoData(fcinfo, &(peraggstate->finalfn), 1, perfuncstate->winCollation, (Node*)winstate, NULL);
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fcinfo.arg[0] = peraggstate->transValue;
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fcinfo.argnull[0] = peraggstate->transValueIsNull;
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fcinfo.argTypes[0] = InvalidOid;
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if (fcinfo.flinfo->fn_strict && peraggstate->transValueIsNull) {
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/* don't call a strict function with NULL inputs */
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*result = (Datum)0;
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*is_null = true;
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} else {
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*result = FunctionCallInvoke(&fcinfo);
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*is_null = fcinfo.isnull;
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}
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} else {
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*result = peraggstate->transValue;
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*is_null = 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 && !*is_null &&
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!MemoryContextContains(CurrentMemoryContext, DatumGetPointer(*result)))
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*result = datumCopy(*result, peraggstate->resulttypeByVal, peraggstate->resulttypeLen);
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MemoryContextSwitchTo(old_context);
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}
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/*
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* eval_windowaggregates
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* evaluate plain aggregates being used as window functions
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*
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* Much of this is duplicated from nodeAgg.c. But NOTE that we expect to be
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* able to call aggregate final functions repeatedly after aggregating more
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* data onto the same transition value. This is not a behavior required by
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* nodeAgg.c.
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*/
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static void eval_windowaggregates(WindowAggState* winstate)
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{
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WindowStatePerAgg peraggstate;
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int wfuncno, num_aggs;
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int i;
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MemoryContext old_context;
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ExprContext* econtext = NULL;
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WindowObject agg_winobj;
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TupleTableSlot* agg_row_slot = NULL;
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num_aggs = winstate->numaggs;
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if (num_aggs == 0) {
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return; /* nothing to do */
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}
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/* final output execution is in ps_ExprContext */
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econtext = winstate->ss.ps.ps_ExprContext;
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agg_winobj = winstate->agg_winobj;
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agg_row_slot = winstate->agg_row_slot;
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/*
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* Currently, we support only a subset of the SQL-standard window framing
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* rules.
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*
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* If the frame start is UNBOUNDED_PRECEDING, the window frame consists of
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* a contiguous group of rows extending forward from the start of the
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* partition, and rows only enter the frame, never exit it, as the current
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* row advances forward. This makes it possible to use an incremental
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* strategy for evaluating aggregates: we run the transition function for
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* each row added to the frame, and run the final function whenever we
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* need the current aggregate value. This is considerably more efficient
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* than the naive approach of re-running the entire aggregate calculation
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* for each current row. It does assume that the final function doesn't
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* damage the running transition value, but we have the same assumption in
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* nodeAgg.c too (when it rescans an existing hash table).
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*
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* For other frame start rules, we discard the aggregate state and re-run
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* the aggregates whenever the frame head row moves. We can still
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* optimize as above whenever successive rows share the same frame head.
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*
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* In many common cases, multiple rows share the same frame and hence the
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* same aggregate value. (In particular, if there's no ORDER BY in a RANGE
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* window, then all rows are peers and so they all have window frame equal
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* to the whole partition.) We optimize such cases by calculating the
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* aggregate value once when we reach the first row of a peer group, and
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* then returning the saved value for all subsequent rows.
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*
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* 'aggregatedupto' keeps track of the first row that has not yet been
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* accumulated into the aggregate transition values. Whenever we start a
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* new peer group, we accumulate forward to the end of the peer group.
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*
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* Rerunning aggregates from the frame start can be pretty slow. For
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* some aggregates like SUM and COUNT we could avoid that by implementing
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* a "negative transition function" that would be called for each row as
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* it exits the frame. We'd have to think about avoiding recalculation of
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* volatile arguments of aggregate functions, too.
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*/
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/*
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* First, update the frame head position.
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*/
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update_frameheadpos(agg_winobj, winstate->temp_slot_1);
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/*
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* Initialize aggregates on first call for partition, or if the frame head
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* position moved since last time.
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*/
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if (winstate->currentpos == 0 || winstate->frameheadpos != winstate->aggregatedbase) {
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/*
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* Discard transient aggregate values
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*/
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MemoryContextResetAndDeleteChildren(winstate->aggcontext);
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for (i = 0; i < num_aggs; i++) {
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peraggstate = &winstate->peragg[i];
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wfuncno = peraggstate->wfuncno;
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initialize_windowaggregate(winstate, &winstate->perfunc[wfuncno], peraggstate);
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}
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/*
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* If we created a mark pointer for aggregates, keep it pushed up to
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* frame head, so that tuplestore can discard unnecessary rows.
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*/
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if (agg_winobj->markptr >= 0)
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WinSetMarkPosition(agg_winobj, winstate->frameheadpos);
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/*
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* Initialize for loop below
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*/
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(void)ExecClearTuple(agg_row_slot);
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winstate->aggregatedbase = winstate->frameheadpos;
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winstate->aggregatedupto = winstate->frameheadpos;
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}
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/*
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* In UNBOUNDED_FOLLOWING mode, we don't have to recalculate aggregates
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* except when the frame head moves. In END_CURRENT_ROW mode, we only
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* have to recalculate when the frame head moves or currentpos has
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* advanced past the place we'd aggregated up to. Check for these cases
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* and if so, reuse the saved result values.
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*/
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if ((winstate->frameOptions & (FRAMEOPTION_END_UNBOUNDED_FOLLOWING | FRAMEOPTION_END_CURRENT_ROW)) &&
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winstate->aggregatedbase <= winstate->currentpos && winstate->aggregatedupto > winstate->currentpos) {
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for (i = 0; i < num_aggs; i++) {
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peraggstate = &winstate->peragg[i];
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wfuncno = peraggstate->wfuncno;
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econtext->ecxt_aggvalues[wfuncno] = peraggstate->resultValue;
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econtext->ecxt_aggnulls[wfuncno] = peraggstate->resultValueIsNull;
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}
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return;
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}
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/*
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* Advance until we reach a row not in frame (or end of partition).
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*
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* Note the loop invariant: agg_row_slot is either empty or holds the row
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* at position aggregatedupto. We advance aggregatedupto after processing
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* a row.
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*/
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for (;;) {
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/* Fetch next row if we didn't already */
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if (TupIsNull(agg_row_slot)) {
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if (!window_gettupleslot(agg_winobj, winstate->aggregatedupto, agg_row_slot))
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break; /* must be end of partition */
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}
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/* Exit loop (for now) if not in frame */
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if (!row_is_in_frame(winstate, winstate->aggregatedupto, agg_row_slot))
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break;
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/* Set tuple context for evaluation of aggregate arguments */
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winstate->tmpcontext->ecxt_outertuple = agg_row_slot;
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/* Accumulate row into the aggregates */
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for (i = 0; i < num_aggs; i++) {
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peraggstate = &winstate->peragg[i];
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wfuncno = peraggstate->wfuncno;
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advance_windowaggregate(winstate, &winstate->perfunc[wfuncno], peraggstate);
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}
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/* Reset per-input-tuple context after each tuple */
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ResetExprContext(winstate->tmpcontext);
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/* And advance the aggregated-row state */
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winstate->aggregatedupto++;
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(void)ExecClearTuple(agg_row_slot);
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}
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/*
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* finalize aggregates and fill result/isnull fields.
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*/
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for (i = 0; i < num_aggs; i++) {
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Datum* result = NULL;
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bool* is_null = NULL;
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peraggstate = &winstate->peragg[i];
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wfuncno = peraggstate->wfuncno;
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result = &econtext->ecxt_aggvalues[wfuncno];
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is_null = &econtext->ecxt_aggnulls[wfuncno];
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finalize_windowaggregate(winstate, &winstate->perfunc[wfuncno], peraggstate, result, is_null);
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/*
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* save the result in case next row shares the same frame.
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*
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* XXX in some framing modes, eg ROWS/END_CURRENT_ROW, we can know in
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* advance that the next row can't possibly share the same frame. Is
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* it worth detecting that and skipping this code?
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*/
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if (!peraggstate->resulttypeByVal) {
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/*
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* clear old resultValue in order not to leak memory. (Note: the
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* new result can't possibly be the same datum as old resultValue,
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* because we never passed it to the trans function.)
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*/
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if (!peraggstate->resultValueIsNull)
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pfree(DatumGetPointer(peraggstate->resultValue));
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/*
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* If pass-by-ref, copy it into our aggregate context.
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*/
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if (!*is_null) {
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old_context = MemoryContextSwitchTo(winstate->aggcontext);
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peraggstate->resultValue = datumCopy(*result, peraggstate->resulttypeByVal, peraggstate->resulttypeLen);
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MemoryContextSwitchTo(old_context);
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}
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} else {
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peraggstate->resultValue = *result;
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}
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peraggstate->resultValueIsNull = *is_null;
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}
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}
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/*
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* eval_windowfunction
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*
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* Arguments of window functions are not evaluated here, because a window
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* function can need random access to arbitrary rows in the partition.
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* The window function uses the special WinGetFuncArgInPartition and
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* WinGetFuncArgInFrame functions to evaluate the arguments for the rows
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* it wants.
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*/
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static void eval_windowfunction(WindowAggState* winstate, WindowStatePerFunc perfuncstate, Datum* result, bool* is_null)
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{
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FunctionCallInfoData fcinfo;
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MemoryContext old_context;
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errno_t errorno = EOK;
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old_context = MemoryContextSwitchTo(winstate->ss.ps.ps_ExprContext->ecxt_per_tuple_memory);
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/*
|
|
* We don't pass any normal arguments to a window function, but we do pass
|
|
* it the number of arguments, in order to permit window function
|
|
* implementations to support varying numbers of arguments. The real info
|
|
* goes through the WindowObject, which is passed via fcinfo->context.
|
|
*/
|
|
InitFunctionCallInfoData(fcinfo,
|
|
&(perfuncstate->flinfo),
|
|
perfuncstate->numArguments,
|
|
perfuncstate->winCollation,
|
|
(Node*)perfuncstate->winobj,
|
|
NULL);
|
|
/* Just in case, make all the regular argument slots be null */
|
|
errorno = memset_s(fcinfo.argnull, perfuncstate->numArguments, true, perfuncstate->numArguments);
|
|
securec_check(errorno, "\0", "\0");
|
|
|
|
*result = FunctionCallInvoke(&fcinfo);
|
|
*is_null = fcinfo.isnull;
|
|
|
|
/*
|
|
* Make sure pass-by-ref data is allocated in the appropriate context. (We
|
|
* need this in case the function returns a pointer into some short-lived
|
|
* tuple, as is entirely possible.)
|
|
*/
|
|
if (!perfuncstate->resulttypeByVal && !fcinfo.isnull &&
|
|
!MemoryContextContains(CurrentMemoryContext, DatumGetPointer(*result)))
|
|
*result = datumCopy(*result, perfuncstate->resulttypeByVal, perfuncstate->resulttypeLen);
|
|
|
|
MemoryContextSwitchTo(old_context);
|
|
}
|
|
|
|
/*
|
|
* begin_partition
|
|
* Start buffering rows of the next partition.
|
|
*/
|
|
static void begin_partition(WindowAggState* winstate)
|
|
{
|
|
PlanState* outer_plan = outerPlanState(winstate);
|
|
int numfuncs = winstate->numfuncs;
|
|
int i;
|
|
Plan* plan = winstate->ss.ps.plan;
|
|
|
|
winstate->partition_spooled = false;
|
|
winstate->framehead_valid = false;
|
|
winstate->frametail_valid = false;
|
|
winstate->spooled_rows = 0;
|
|
winstate->currentpos = 0;
|
|
winstate->frameheadpos = 0;
|
|
winstate->frametailpos = -1;
|
|
(void)ExecClearTuple(winstate->agg_row_slot);
|
|
|
|
int64 operator_mem = SET_NODEMEM(plan->operatorMemKB[0], plan->dop);
|
|
int64 max_mem = (plan->operatorMaxMem > 0) ? SET_NODEMEM(plan->operatorMaxMem, plan->dop) : 0;
|
|
|
|
/*
|
|
* If this is the very first partition, we need to fetch the first input
|
|
* row to store in first_part_slot.
|
|
*/
|
|
if (TupIsNull(winstate->first_part_slot)) {
|
|
TupleTableSlot* outerslot = ExecProcNode(outer_plan);
|
|
|
|
if (!TupIsNull(outerslot))
|
|
ExecCopySlot(winstate->first_part_slot, outerslot);
|
|
else {
|
|
/* outer plan is empty, so we have nothing to do */
|
|
winstate->partition_spooled = true;
|
|
winstate->more_partitions = false;
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* Create new tuplestore for this partition */
|
|
winstate->buffer =
|
|
tuplestore_begin_heap(false, false, operator_mem, max_mem, plan->plan_node_id, SET_DOP(plan->dop), true);
|
|
|
|
/*
|
|
* Set up read pointers for the tuplestore. The current pointer doesn't
|
|
* need BACKWARD capability, but the per-window-function read pointers do,
|
|
* and the aggregate pointer does if frame start is movable.
|
|
*/
|
|
winstate->current_ptr = 0; /* read pointer 0 is pre-allocated */
|
|
|
|
/* reset default REWIND capability bit for current ptr */
|
|
tuplestore_set_eflags(winstate->buffer, 0);
|
|
|
|
/* create read pointers for aggregates, if needed */
|
|
if (winstate->numaggs > 0) {
|
|
WindowObject agg_winobj = winstate->agg_winobj;
|
|
int readptr_flags = 0;
|
|
|
|
/* If the frame head is potentially movable ... */
|
|
if (!(winstate->frameOptions & FRAMEOPTION_START_UNBOUNDED_PRECEDING)) {
|
|
/* ... create a mark pointer to track the frame head */
|
|
agg_winobj->markptr = tuplestore_alloc_read_pointer(winstate->buffer, 0);
|
|
/* and the read pointer will need BACKWARD capability */
|
|
readptr_flags |= EXEC_FLAG_BACKWARD;
|
|
}
|
|
|
|
agg_winobj->readptr = tuplestore_alloc_read_pointer(winstate->buffer, readptr_flags);
|
|
agg_winobj->markpos = -1;
|
|
agg_winobj->seekpos = -1;
|
|
|
|
/* Also reset the row counters for aggregates */
|
|
winstate->aggregatedbase = 0;
|
|
winstate->aggregatedupto = 0;
|
|
}
|
|
|
|
/* create mark and read pointers for each real window function */
|
|
for (i = 0; i < numfuncs; i++) {
|
|
WindowStatePerFunc perfuncstate = &(winstate->perfunc[i]);
|
|
|
|
if (!perfuncstate->plain_agg) {
|
|
WindowObject winobj = perfuncstate->winobj;
|
|
|
|
winobj->markptr = tuplestore_alloc_read_pointer(winstate->buffer, 0);
|
|
winobj->readptr = tuplestore_alloc_read_pointer(winstate->buffer, EXEC_FLAG_BACKWARD);
|
|
winobj->markpos = -1;
|
|
winobj->seekpos = -1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Store the first tuple into the tuplestore (it's always available now;
|
|
* we either read it above, or saved it at the end of previous partition)
|
|
*/
|
|
tuplestore_puttupleslot(winstate->buffer, winstate->first_part_slot);
|
|
winstate->spooled_rows++;
|
|
}
|
|
|
|
/*
|
|
* Read tuples from the outer node, up to and including position 'pos', and
|
|
* store them into the tuplestore. If pos is -1, reads the whole partition.
|
|
*/
|
|
static void spool_tuples(WindowAggState* winstate, int64 pos)
|
|
{
|
|
WindowAgg* node = (WindowAgg*)winstate->ss.ps.plan;
|
|
PlanState* outer_plan = NULL;
|
|
TupleTableSlot* outer_slot = NULL;
|
|
MemoryContext old_context;
|
|
|
|
if (!winstate->buffer)
|
|
return; /* just a safety check */
|
|
if (winstate->partition_spooled)
|
|
return; /* whole partition done already */
|
|
|
|
/*
|
|
* If the tuplestore has spilled to disk, alternate reading and writing
|
|
* becomes quite expensive due to frequent buffer flushes. It's cheaper
|
|
* to force the entire partition to get spooled in one go.
|
|
*/
|
|
if (!tuplestore_in_memory(winstate->buffer))
|
|
pos = -1;
|
|
|
|
outer_plan = outerPlanState(winstate);
|
|
|
|
/* Must be in query context to call outerplan */
|
|
old_context = MemoryContextSwitchTo(winstate->ss.ps.ps_ExprContext->ecxt_per_query_memory);
|
|
|
|
while (winstate->spooled_rows <= pos || pos == -1) {
|
|
outer_slot = ExecProcNode(outer_plan);
|
|
if (TupIsNull(outer_slot)) {
|
|
/* reached the end of the last partition */
|
|
winstate->partition_spooled = true;
|
|
winstate->more_partitions = false;
|
|
break;
|
|
}
|
|
|
|
if (node->partNumCols > 0) {
|
|
/* Check if this tuple still belongs to the current partition */
|
|
if (!execTuplesMatch(winstate->first_part_slot, outer_slot, node->partNumCols, node->partColIdx,
|
|
winstate->partEqfunctions, winstate->tmpcontext->ecxt_per_tuple_memory)) {
|
|
/*
|
|
* end of partition; copy the tuple for the next cycle.
|
|
*/
|
|
ExecCopySlot(winstate->first_part_slot, outer_slot);
|
|
winstate->partition_spooled = true;
|
|
winstate->more_partitions = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Still in partition, so save it into the tuplestore */
|
|
tuplestore_puttupleslot(winstate->buffer, outer_slot);
|
|
winstate->spooled_rows++;
|
|
}
|
|
|
|
MemoryContextSwitchTo(old_context);
|
|
}
|
|
|
|
/*
|
|
* release_partition
|
|
* clear information kept within a partition, including
|
|
* tuplestore and aggregate results.
|
|
*/
|
|
static void release_partition(WindowAggState* winstate)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < winstate->numfuncs; i++) {
|
|
WindowStatePerFunc perfuncstate = &(winstate->perfunc[i]);
|
|
|
|
/* Release any partition-local state of this window function */
|
|
if (perfuncstate->winobj)
|
|
perfuncstate->winobj->localmem = NULL;
|
|
}
|
|
|
|
/*
|
|
* Release all partition-local memory (in particular, any partition-local
|
|
* state that we might have trashed our pointers to in the above loop, and
|
|
* any aggregate temp data). We don't rely on retail pfree because some
|
|
* aggregates might have allocated data we don't have direct pointers to.
|
|
*/
|
|
MemoryContextResetAndDeleteChildren(winstate->partcontext);
|
|
MemoryContextResetAndDeleteChildren(winstate->aggcontext);
|
|
|
|
if (winstate->buffer)
|
|
tuplestore_end(winstate->buffer);
|
|
winstate->buffer = NULL;
|
|
winstate->partition_spooled = false;
|
|
}
|
|
|
|
/*
|
|
* row_is_in_frame
|
|
* Determine whether a row is in the current row's window frame according
|
|
* to our window framing rule
|
|
*
|
|
* The caller must have already determined that the row is in the partition
|
|
* and fetched it into a slot. This function just encapsulates the framing
|
|
* rules.
|
|
*/
|
|
static bool row_is_in_frame(WindowAggState* winstate, int64 pos, TupleTableSlot* slot)
|
|
{
|
|
int frame_options = winstate->frameOptions;
|
|
|
|
Assert(pos >= 0); /* else caller error */
|
|
|
|
/* First, check frame starting conditions */
|
|
if (frame_options & FRAMEOPTION_START_CURRENT_ROW) {
|
|
if (frame_options & FRAMEOPTION_ROWS) {
|
|
/* rows before current row are out of frame */
|
|
if (pos < winstate->currentpos)
|
|
return false;
|
|
} else if (frame_options & FRAMEOPTION_RANGE) {
|
|
/* preceding row that is not peer is out of frame */
|
|
if (pos < winstate->currentpos && !are_peers(winstate, slot, winstate->ss.ss_ScanTupleSlot))
|
|
return false;
|
|
} else
|
|
Assert(false);
|
|
} else if (frame_options & FRAMEOPTION_START_VALUE) {
|
|
if (frame_options & FRAMEOPTION_ROWS) {
|
|
int64 offset = DatumGetInt64(winstate->startOffsetValue);
|
|
|
|
/* rows before current row + offset are out of frame */
|
|
if (frame_options & FRAMEOPTION_START_VALUE_PRECEDING)
|
|
offset = -offset;
|
|
|
|
if (pos < winstate->currentpos + offset)
|
|
return false;
|
|
} else if (frame_options & FRAMEOPTION_RANGE) {
|
|
/* parser should have rejected this */
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("window frame with value offset is not implemented")));
|
|
} else
|
|
Assert(false);
|
|
}
|
|
|
|
/* Okay so far, now check frame ending conditions */
|
|
if (frame_options & FRAMEOPTION_END_CURRENT_ROW) {
|
|
if (frame_options & FRAMEOPTION_ROWS) {
|
|
/* rows after current row are out of frame */
|
|
if (pos > winstate->currentpos)
|
|
return false;
|
|
} else if (frame_options & FRAMEOPTION_RANGE) {
|
|
/* following row that is not peer is out of frame */
|
|
if (pos > winstate->currentpos && !are_peers(winstate, slot, winstate->ss.ss_ScanTupleSlot))
|
|
return false;
|
|
} else
|
|
Assert(false);
|
|
} else if (frame_options & FRAMEOPTION_END_VALUE) {
|
|
if (frame_options & FRAMEOPTION_ROWS) {
|
|
int64 offset = DatumGetInt64(winstate->endOffsetValue);
|
|
|
|
/* rows after current row + offset are out of frame */
|
|
if (frame_options & FRAMEOPTION_END_VALUE_PRECEDING)
|
|
offset = -offset;
|
|
|
|
if (pos > winstate->currentpos + offset)
|
|
return false;
|
|
} else if (frame_options & FRAMEOPTION_RANGE) {
|
|
/* parser should have rejected this */
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("window frame with value offset is not implemented")));
|
|
} else
|
|
Assert(false);
|
|
}
|
|
|
|
/* If we get here, it's in frame */
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* update_frameheadpos
|
|
* make frameheadpos valid for the current row
|
|
*
|
|
* Uses the winobj's read pointer for any required fetches; hence, if the
|
|
* frame mode is one that requires row comparisons, the winobj's mark must
|
|
* not be past the currently known frame head. Also uses the specified slot
|
|
* for any required fetches.
|
|
*/
|
|
static void update_frameheadpos(WindowObject winobj, TupleTableSlot* slot)
|
|
{
|
|
WindowAggState* winstate = winobj->winstate;
|
|
WindowAgg* node = (WindowAgg*)winstate->ss.ps.plan;
|
|
int frame_options = winstate->frameOptions;
|
|
|
|
if (winstate->framehead_valid)
|
|
return; /* already known for current row */
|
|
|
|
bool isFrameHead = frame_options & FRAMEOPTION_START_UNBOUNDED_PRECEDING;
|
|
if (isFrameHead) {
|
|
/* In UNBOUNDED PRECEDING mode, frame head is always row 0 */
|
|
winstate->frameheadpos = 0;
|
|
winstate->framehead_valid = true;
|
|
} else if (frame_options & FRAMEOPTION_START_CURRENT_ROW) {
|
|
if (frame_options & FRAMEOPTION_ROWS) {
|
|
/* In ROWS mode, frame head is the same as current */
|
|
winstate->frameheadpos = winstate->currentpos;
|
|
winstate->framehead_valid = true;
|
|
} else if (frame_options & FRAMEOPTION_RANGE) {
|
|
int64 fhprev;
|
|
|
|
/* If no ORDER BY, all rows are peers with each other */
|
|
if (node->ordNumCols == 0) {
|
|
winstate->frameheadpos = 0;
|
|
winstate->framehead_valid = true;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* In RANGE START_CURRENT mode, frame head is the first row that
|
|
* is a peer of current row. We search backwards from current,
|
|
* which could be a bit inefficient if peer sets are large. Might
|
|
* be better to have a separate read pointer that moves forward
|
|
* tracking the frame head.
|
|
*/
|
|
fhprev = winstate->currentpos - 1;
|
|
for (;;) {
|
|
/* assume the frame head can't go backwards */
|
|
if (fhprev < winstate->frameheadpos)
|
|
break;
|
|
if (!window_gettupleslot(winobj, fhprev, slot))
|
|
break; /* start of partition */
|
|
if (!are_peers(winstate, slot, winstate->ss.ss_ScanTupleSlot))
|
|
break; /* not peer of current row */
|
|
fhprev--;
|
|
}
|
|
winstate->frameheadpos = fhprev + 1;
|
|
winstate->framehead_valid = true;
|
|
} else
|
|
Assert(false);
|
|
} else if (frame_options & FRAMEOPTION_START_VALUE) {
|
|
if (frame_options & FRAMEOPTION_ROWS) {
|
|
/* In ROWS mode, bound is physically n before/after current */
|
|
int64 offset = DatumGetInt64(winstate->startOffsetValue);
|
|
|
|
if (frame_options & FRAMEOPTION_START_VALUE_PRECEDING)
|
|
offset = -offset;
|
|
|
|
winstate->frameheadpos = winstate->currentpos + offset;
|
|
/* frame head can't go before first row */
|
|
if (winstate->frameheadpos < 0)
|
|
winstate->frameheadpos = 0;
|
|
else if (winstate->frameheadpos > winstate->currentpos) {
|
|
/* make sure frameheadpos is not past end of partition */
|
|
spool_tuples(winstate, winstate->frameheadpos - 1);
|
|
if (winstate->frameheadpos > winstate->spooled_rows)
|
|
winstate->frameheadpos = winstate->spooled_rows;
|
|
}
|
|
winstate->framehead_valid = true;
|
|
} else if (frame_options & FRAMEOPTION_RANGE) {
|
|
/* parser should have rejected this */
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("window frame with value offset is not implemented")));
|
|
} else
|
|
Assert(false);
|
|
} else
|
|
Assert(false);
|
|
}
|
|
|
|
/*
|
|
* update_frametailpos
|
|
* make frametailpos valid for the current row
|
|
*
|
|
* Uses the winobj's read pointer for any required fetches; hence, if the
|
|
* frame mode is one that requires row comparisons, the winobj's mark must
|
|
* not be past the currently known frame tail. Also uses the specified slot
|
|
* for any required fetches.
|
|
*/
|
|
static void update_frametailpos(WindowObject winobj, TupleTableSlot* slot)
|
|
{
|
|
WindowAggState* winstate = winobj->winstate;
|
|
WindowAgg* node = (WindowAgg*)winstate->ss.ps.plan;
|
|
int frame_options = winstate->frameOptions;
|
|
|
|
if (winstate->frametail_valid)
|
|
return; /* already known for current row */
|
|
|
|
if (frame_options & FRAMEOPTION_END_UNBOUNDED_FOLLOWING) {
|
|
/* In UNBOUNDED FOLLOWING mode, all partition rows are in frame */
|
|
spool_tuples(winstate, -1);
|
|
winstate->frametailpos = winstate->spooled_rows - 1;
|
|
winstate->frametail_valid = true;
|
|
} else if (frame_options & FRAMEOPTION_END_CURRENT_ROW) {
|
|
if (frame_options & FRAMEOPTION_ROWS) {
|
|
/* In ROWS mode, exactly the rows up to current are in frame */
|
|
winstate->frametailpos = winstate->currentpos;
|
|
winstate->frametail_valid = true;
|
|
} else if (frame_options & FRAMEOPTION_RANGE) {
|
|
int64 ftnext;
|
|
|
|
/* If no ORDER BY, all rows are peers with each other */
|
|
if (node->ordNumCols == 0) {
|
|
spool_tuples(winstate, -1);
|
|
winstate->frametailpos = winstate->spooled_rows - 1;
|
|
winstate->frametail_valid = true;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Else we have to search for the first non-peer of the current
|
|
* row. We assume the current value of frametailpos is a lower
|
|
* bound on the possible frame tail location, ie, frame tail never
|
|
* goes backward, and that currentpos is also a lower bound, ie,
|
|
* frame end always >= current row.
|
|
*/
|
|
ftnext = Max(winstate->frametailpos, winstate->currentpos) + 1;
|
|
for (;;) {
|
|
if (!window_gettupleslot(winobj, ftnext, slot))
|
|
break; /* end of partition */
|
|
if (!are_peers(winstate, slot, winstate->ss.ss_ScanTupleSlot))
|
|
break; /* not peer of current row */
|
|
ftnext++;
|
|
}
|
|
winstate->frametailpos = ftnext - 1;
|
|
winstate->frametail_valid = true;
|
|
} else
|
|
Assert(false);
|
|
} else if (frame_options & FRAMEOPTION_END_VALUE) {
|
|
if (frame_options & FRAMEOPTION_ROWS) {
|
|
/* In ROWS mode, bound is physically n before/after current */
|
|
int64 offset = DatumGetInt64(winstate->endOffsetValue);
|
|
|
|
if (frame_options & FRAMEOPTION_END_VALUE_PRECEDING)
|
|
offset = -offset;
|
|
|
|
winstate->frametailpos = winstate->currentpos + offset;
|
|
/* smallest allowable value of frametailpos is -1 */
|
|
if (winstate->frametailpos < 0)
|
|
winstate->frametailpos = -1;
|
|
else if (winstate->frametailpos > winstate->currentpos) {
|
|
/* make sure frametailpos is not past last row of partition */
|
|
spool_tuples(winstate, winstate->frametailpos);
|
|
if (winstate->frametailpos >= winstate->spooled_rows)
|
|
winstate->frametailpos = winstate->spooled_rows - 1;
|
|
}
|
|
winstate->frametail_valid = true;
|
|
} else if (frame_options & FRAMEOPTION_RANGE) {
|
|
/* parser should have rejected this */
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("window frame with value offset is not implemented")));
|
|
} else
|
|
Assert(false);
|
|
} else
|
|
Assert(false);
|
|
}
|
|
|
|
/* -----------------
|
|
* ExecWindowAgg
|
|
*
|
|
* ExecWindowAgg receives tuples from its outer subplan and
|
|
* stores them into a tuplestore, then processes window functions.
|
|
* This node doesn't reduce nor qualify any row so the number of
|
|
* returned rows is exactly the same as its outer subplan's result
|
|
* (ignoring the case of SRFs in the targetlist, that is).
|
|
* -----------------
|
|
*/
|
|
TupleTableSlot* ExecWindowAgg(WindowAggState* winstate)
|
|
{
|
|
TupleTableSlot* result = NULL;
|
|
ExprDoneCond is_done;
|
|
ExprContext* econtext = NULL;
|
|
int i;
|
|
int numfuncs;
|
|
|
|
if (winstate->all_done)
|
|
return NULL;
|
|
|
|
/*
|
|
* Check to see if we're still projecting out tuples from a previous
|
|
* output tuple (because there is a function-returning-set in the
|
|
* projection expressions). If so, try to project another one.
|
|
*/
|
|
if (winstate->ss.ps.ps_TupFromTlist) {
|
|
TupleTableSlot* res = ExecProject(winstate->ss.ps.ps_ProjInfo, &is_done);
|
|
if (is_done == ExprMultipleResult)
|
|
return res;
|
|
/* Done with that source tuple... */
|
|
winstate->ss.ps.ps_TupFromTlist = false;
|
|
}
|
|
|
|
/*
|
|
* Compute frame offset values, if any, during first call.
|
|
*/
|
|
if (winstate->all_first) {
|
|
int frameOptions = winstate->frameOptions;
|
|
ExprContext* exprContext = winstate->ss.ps.ps_ExprContext;
|
|
Datum value;
|
|
bool isnull = false;
|
|
int16 len;
|
|
bool byval = false;
|
|
|
|
if (frameOptions & FRAMEOPTION_START_VALUE) {
|
|
Assert(winstate->startOffset != NULL);
|
|
value = ExecEvalExprSwitchContext(winstate->startOffset, exprContext, &isnull, NULL);
|
|
if (isnull)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("frame starting offset must not be null")));
|
|
/* copy value into query-lifespan context */
|
|
get_typlenbyval(exprType((Node*)winstate->startOffset->expr), &len, &byval);
|
|
winstate->startOffsetValue = datumCopy(value, byval, len);
|
|
if (frameOptions & FRAMEOPTION_ROWS) {
|
|
/* value is known to be int8 */
|
|
int64 offset = DatumGetInt64(value);
|
|
if (offset < 0)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("frame starting offset must not be negative")));
|
|
}
|
|
}
|
|
if (frameOptions & FRAMEOPTION_END_VALUE) {
|
|
Assert(winstate->endOffset != NULL);
|
|
value = ExecEvalExprSwitchContext(winstate->endOffset, exprContext, &isnull, NULL);
|
|
if (isnull)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("frame ending offset must not be null")));
|
|
/* copy value into query-lifespan context */
|
|
get_typlenbyval(exprType((Node*)winstate->endOffset->expr), &len, &byval);
|
|
winstate->endOffsetValue = datumCopy(value, byval, len);
|
|
if (frameOptions & FRAMEOPTION_ROWS) {
|
|
/* value is known to be int8 */
|
|
int64 offset = DatumGetInt64(value);
|
|
if (offset < 0)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("frame ending offset must not be negative")));
|
|
}
|
|
}
|
|
winstate->all_first = false;
|
|
}
|
|
|
|
restart:
|
|
if (winstate->buffer == NULL) {
|
|
/* Initialize for first partition and set current row = 0 */
|
|
begin_partition(winstate);
|
|
/* If there are no input rows, we'll detect that and exit below */
|
|
} else {
|
|
/* Advance current row within partition */
|
|
winstate->currentpos++;
|
|
/* This might mean that the frame moves, too */
|
|
winstate->framehead_valid = false;
|
|
winstate->frametail_valid = false;
|
|
}
|
|
|
|
/*
|
|
* Spool all tuples up to and including the current row, if we haven't
|
|
* already
|
|
*/
|
|
spool_tuples(winstate, winstate->currentpos);
|
|
|
|
/* Move to the next partition if we reached the end of this partition */
|
|
if (winstate->partition_spooled && winstate->currentpos >= winstate->spooled_rows) {
|
|
release_partition(winstate);
|
|
|
|
if (winstate->more_partitions) {
|
|
begin_partition(winstate);
|
|
Assert(winstate->spooled_rows > 0);
|
|
} else {
|
|
winstate->all_done = true;
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
/* final output execution is in ps_ExprContext */
|
|
econtext = winstate->ss.ps.ps_ExprContext;
|
|
|
|
/* Clear the per-output-tuple context for current row */
|
|
ResetExprContext(econtext);
|
|
|
|
/*
|
|
* Read the current row from the tuplestore, and save in ScanTupleSlot.
|
|
* (We can't rely on the outerplan's output slot because we may have to
|
|
* read beyond the current row. Also, we have to actually copy the row
|
|
* out of the tuplestore, since window function evaluation might cause the
|
|
* tuplestore to dump its state to disk.)
|
|
*
|
|
* Current row must be in the tuplestore, since we spooled it above.
|
|
*/
|
|
tuplestore_select_read_pointer(winstate->buffer, winstate->current_ptr);
|
|
if (!tuplestore_gettupleslot(winstate->buffer, true, true, winstate->ss.ss_ScanTupleSlot))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATA_EXCEPTION),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("cannot get result from tuplestore for WinwdowsAgg")));
|
|
|
|
/*
|
|
* Evaluate true window functions
|
|
*/
|
|
numfuncs = winstate->numfuncs;
|
|
for (i = 0; i < numfuncs; i++) {
|
|
WindowStatePerFunc perfuncstate = &(winstate->perfunc[i]);
|
|
|
|
if (perfuncstate->plain_agg)
|
|
continue;
|
|
eval_windowfunction(winstate,
|
|
perfuncstate,
|
|
&(econtext->ecxt_aggvalues[perfuncstate->wfuncstate->wfuncno]),
|
|
&(econtext->ecxt_aggnulls[perfuncstate->wfuncstate->wfuncno]));
|
|
}
|
|
|
|
/*
|
|
* Evaluate aggregates
|
|
*/
|
|
if (winstate->numaggs > 0)
|
|
eval_windowaggregates(winstate);
|
|
|
|
/*
|
|
* Truncate any no-longer-needed rows from the tuplestore.
|
|
*/
|
|
tuplestore_trim(winstate->buffer);
|
|
|
|
/*
|
|
* Form and return a projection tuple using the windowfunc results and the
|
|
* current row. Setting ecxt_outertuple arranges that any Vars will be
|
|
* evaluated with respect to that row.
|
|
*/
|
|
econtext->ecxt_outertuple = winstate->ss.ss_ScanTupleSlot;
|
|
result = ExecProject(winstate->ss.ps.ps_ProjInfo, &is_done);
|
|
|
|
if (is_done == ExprEndResult) {
|
|
/* SRF in tlist returned no rows, so advance to next input tuple */
|
|
goto restart;
|
|
}
|
|
|
|
winstate->ss.ps.ps_TupFromTlist = (is_done == ExprMultipleResult);
|
|
return result;
|
|
}
|
|
|
|
/* -----------------
|
|
* ExecInitWindowAgg
|
|
*
|
|
* Creates the run-time information for the WindowAgg node produced by the
|
|
* planner and initializes its outer subtree
|
|
* -----------------
|
|
*/
|
|
WindowAggState* ExecInitWindowAgg(WindowAgg* node, EState* estate, int eflags)
|
|
{
|
|
Plan* left_tree = NULL;
|
|
ExprContext* econtext = NULL;
|
|
ExprContext* tmp_context = NULL;
|
|
WindowStatePerFunc perfunc = NULL;
|
|
WindowStatePerAgg peragg;
|
|
int num_funcs;
|
|
int wfuncno;
|
|
int numaggs;
|
|
int aggno;
|
|
ListCell* l = NULL;
|
|
|
|
/* check for unsupported flags */
|
|
Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
|
|
|
|
/*
|
|
* create state structure
|
|
*/
|
|
WindowAggState* winstate = makeNode(WindowAggState);
|
|
winstate->ss.ps.plan = (Plan*)node;
|
|
winstate->ss.ps.state = estate;
|
|
|
|
int64 operator_mem = SET_NODEMEM(((Plan*)node)->operatorMemKB[0], ((Plan*)node)->dop);
|
|
AllocSetContext* set = (AllocSetContext*)(estate->es_query_cxt);
|
|
set->maxSpaceSize = operator_mem * 1024L + SELF_GENRIC_MEMCTX_LIMITATION;
|
|
|
|
/*
|
|
* Create expression contexts. We need two, one for per-input-tuple
|
|
* processing and one for per-output-tuple processing. We cheat a little
|
|
* by using ExecAssignExprContext() to build both.
|
|
*/
|
|
ExecAssignExprContext(estate, &winstate->ss.ps);
|
|
tmp_context = winstate->ss.ps.ps_ExprContext;
|
|
winstate->tmpcontext = tmp_context;
|
|
ExecAssignExprContext(estate, &winstate->ss.ps);
|
|
|
|
/* Create long-lived context for storage of partition-local memory etc */
|
|
winstate->partcontext = AllocSetContextCreate(CurrentMemoryContext,
|
|
"WindowAgg_Partition",
|
|
ALLOCSET_DEFAULT_MINSIZE,
|
|
ALLOCSET_DEFAULT_INITSIZE,
|
|
ALLOCSET_DEFAULT_MAXSIZE);
|
|
|
|
/* Create mid-lived context for aggregate trans values etc */
|
|
winstate->aggcontext = AllocSetContextCreate(CurrentMemoryContext,
|
|
"WindowAgg_Aggregates",
|
|
ALLOCSET_DEFAULT_MINSIZE,
|
|
ALLOCSET_DEFAULT_INITSIZE,
|
|
ALLOCSET_DEFAULT_MAXSIZE);
|
|
|
|
/*
|
|
* tuple table initialization
|
|
*/
|
|
ExecInitScanTupleSlot(estate, &winstate->ss);
|
|
ExecInitResultTupleSlot(estate, &winstate->ss.ps);
|
|
winstate->first_part_slot = ExecInitExtraTupleSlot(estate);
|
|
winstate->agg_row_slot = ExecInitExtraTupleSlot(estate);
|
|
winstate->temp_slot_1 = ExecInitExtraTupleSlot(estate);
|
|
winstate->temp_slot_2 = ExecInitExtraTupleSlot(estate);
|
|
|
|
winstate->ss.ps.targetlist = (List*)ExecInitExpr((Expr*)node->plan.targetlist, (PlanState*)winstate);
|
|
|
|
/*
|
|
* WindowAgg nodes never have quals, since they can only occur at the
|
|
* logical top level of a query (ie, after any WHERE or HAVING filters)
|
|
*/
|
|
Assert(node->plan.qual == NIL);
|
|
winstate->ss.ps.qual = NIL;
|
|
|
|
/*
|
|
* initialize child nodes
|
|
*/
|
|
left_tree = outerPlan(node);
|
|
outerPlanState(winstate) = ExecInitNode(left_tree, estate, eflags);
|
|
|
|
/*
|
|
* initialize source tuple type (which is also the tuple type that we'll
|
|
* store in the tuplestore and use in all our working slots).
|
|
*/
|
|
ExecAssignScanTypeFromOuterPlan(&winstate->ss);
|
|
|
|
ExecSetSlotDescriptor(winstate->first_part_slot, winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor);
|
|
ExecSetSlotDescriptor(winstate->agg_row_slot, winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor);
|
|
ExecSetSlotDescriptor(winstate->temp_slot_1, winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor);
|
|
ExecSetSlotDescriptor(winstate->temp_slot_2, winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor);
|
|
|
|
/*
|
|
* Initialize result tuple type and projection info.
|
|
* result Tuple Table Slot contains virtual tuple, default tableAm type is set to HEAP.
|
|
*/
|
|
ExecAssignResultTypeFromTL(&winstate->ss.ps, TAM_HEAP);
|
|
|
|
ExecAssignProjectionInfo(&winstate->ss.ps, NULL);
|
|
|
|
winstate->ss.ps.ps_TupFromTlist = false;
|
|
|
|
/* Set up data for comparing tuples */
|
|
if (node->partNumCols > 0)
|
|
winstate->partEqfunctions = execTuplesMatchPrepare(node->partNumCols, node->partOperators);
|
|
if (node->ordNumCols > 0)
|
|
winstate->ordEqfunctions = execTuplesMatchPrepare(node->ordNumCols, node->ordOperators);
|
|
|
|
/*
|
|
* WindowAgg nodes use aggvalues and aggnulls as well as Agg nodes.
|
|
*/
|
|
num_funcs = winstate->numfuncs;
|
|
numaggs = winstate->numaggs;
|
|
econtext = winstate->ss.ps.ps_ExprContext;
|
|
econtext->ecxt_aggvalues = (Datum*)palloc0(sizeof(Datum) * num_funcs);
|
|
econtext->ecxt_aggnulls = (bool*)palloc0(sizeof(bool) * num_funcs);
|
|
|
|
/*
|
|
* allocate per-wfunc/per-agg state information.
|
|
*/
|
|
perfunc = (WindowStatePerFunc)palloc0(sizeof(WindowStatePerFuncData) * num_funcs);
|
|
peragg = (WindowStatePerAgg)palloc0(sizeof(WindowStatePerAggData) * numaggs);
|
|
winstate->perfunc = perfunc;
|
|
winstate->peragg = peragg;
|
|
|
|
wfuncno = -1;
|
|
aggno = -1;
|
|
foreach (l, winstate->funcs) {
|
|
WindowFuncExprState* wfuncstate = (WindowFuncExprState*)lfirst(l);
|
|
WindowFunc* wfunc = (WindowFunc*)wfuncstate->xprstate.expr;
|
|
WindowStatePerFunc perfuncstate;
|
|
AclResult aclresult;
|
|
int i;
|
|
|
|
if (wfunc->winref != node->winref) /* planner screwed up? */
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATATYPE_MISMATCH),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("WindowFunc with winref %u assigned to WindowAgg with winref %u",
|
|
wfunc->winref,
|
|
node->winref)));
|
|
|
|
/* Look for a previous duplicate window function */
|
|
for (i = 0; i <= wfuncno; i++) {
|
|
if (equal(wfunc, perfunc[i].wfunc) && !contain_volatile_functions((Node*)wfunc))
|
|
break;
|
|
}
|
|
if (i <= wfuncno) {
|
|
/* Found a match to an existing entry, so just mark it */
|
|
wfuncstate->wfuncno = i;
|
|
continue;
|
|
}
|
|
|
|
/* Nope, so assign a new PerAgg record */
|
|
perfuncstate = &perfunc[++wfuncno];
|
|
|
|
/* Mark WindowFunc state node with assigned index in the result array */
|
|
wfuncstate->wfuncno = wfuncno;
|
|
|
|
/* Check permission to call window function */
|
|
aclresult = pg_proc_aclcheck(wfunc->winfnoid, GetUserId(), ACL_EXECUTE);
|
|
if (aclresult != ACLCHECK_OK)
|
|
aclcheck_error(aclresult, ACL_KIND_PROC, get_func_name(wfunc->winfnoid));
|
|
|
|
/* Fill in the perfuncstate data */
|
|
perfuncstate->wfuncstate = wfuncstate;
|
|
perfuncstate->wfunc = wfunc;
|
|
perfuncstate->numArguments = list_length(wfuncstate->args);
|
|
|
|
fmgr_info_cxt(wfunc->winfnoid, &perfuncstate->flinfo, econtext->ecxt_per_query_memory);
|
|
fmgr_info_set_expr((Node*)wfunc, &perfuncstate->flinfo);
|
|
|
|
perfuncstate->winCollation = wfunc->inputcollid;
|
|
|
|
get_typlenbyval(wfunc->wintype, &perfuncstate->resulttypeLen, &perfuncstate->resulttypeByVal);
|
|
|
|
/*
|
|
* If it's really just a plain aggregate function, we'll emulate the
|
|
* Agg environment for it.
|
|
*/
|
|
perfuncstate->plain_agg = wfunc->winagg;
|
|
if (wfunc->winagg) {
|
|
WindowStatePerAgg peraggstate;
|
|
|
|
perfuncstate->aggno = ++aggno;
|
|
peraggstate = &winstate->peragg[aggno];
|
|
initialize_peragg(winstate, wfunc, peraggstate);
|
|
peraggstate->wfuncno = wfuncno;
|
|
} else {
|
|
WindowObject winobj = makeNode(WindowObjectData);
|
|
|
|
winobj->winstate = winstate;
|
|
winobj->argstates = wfuncstate->args;
|
|
winobj->localmem = NULL;
|
|
perfuncstate->winobj = winobj;
|
|
}
|
|
}
|
|
|
|
/* Update numfuncs, numaggs to match number of unique functions found */
|
|
winstate->numfuncs = wfuncno + 1;
|
|
winstate->numaggs = aggno + 1;
|
|
|
|
/* Set up WindowObject for aggregates, if needed */
|
|
if (winstate->numaggs > 0) {
|
|
WindowObject agg_winobj = makeNode(WindowObjectData);
|
|
|
|
agg_winobj->winstate = winstate;
|
|
agg_winobj->argstates = NIL;
|
|
agg_winobj->localmem = NULL;
|
|
/* make sure markptr = -1 to invalidate. It may not get used */
|
|
agg_winobj->markptr = -1;
|
|
agg_winobj->readptr = -1;
|
|
winstate->agg_winobj = agg_winobj;
|
|
}
|
|
|
|
/* copy frame options to state node for easy access */
|
|
winstate->frameOptions = node->frameOptions;
|
|
|
|
/* initialize frame bound offset expressions */
|
|
winstate->startOffset = ExecInitExpr((Expr*)node->startOffset, (PlanState*)winstate);
|
|
winstate->endOffset = ExecInitExpr((Expr*)node->endOffset, (PlanState*)winstate);
|
|
|
|
winstate->all_first = true;
|
|
winstate->partition_spooled = false;
|
|
winstate->more_partitions = false;
|
|
|
|
return winstate;
|
|
}
|
|
|
|
/* -----------------
|
|
* ExecEndWindowAgg
|
|
* -----------------
|
|
*/
|
|
void ExecEndWindowAgg(WindowAggState* node)
|
|
{
|
|
PlanState* outer_plan = NULL;
|
|
|
|
release_partition(node);
|
|
|
|
pfree_ext(node->perfunc);
|
|
pfree_ext(node->peragg);
|
|
|
|
(void)ExecClearTuple(node->ss.ss_ScanTupleSlot);
|
|
(void)ExecClearTuple(node->first_part_slot);
|
|
(void)ExecClearTuple(node->agg_row_slot);
|
|
(void)ExecClearTuple(node->temp_slot_1);
|
|
(void)ExecClearTuple(node->temp_slot_2);
|
|
|
|
/*
|
|
* Free both the expr contexts.
|
|
*/
|
|
ExecFreeExprContext(&node->ss.ps);
|
|
node->ss.ps.ps_ExprContext = node->tmpcontext;
|
|
ExecFreeExprContext(&node->ss.ps);
|
|
|
|
MemoryContextDelete(node->partcontext);
|
|
MemoryContextDelete(node->aggcontext);
|
|
|
|
outer_plan = outerPlanState(node);
|
|
ExecEndNode(outer_plan);
|
|
}
|
|
|
|
/* -----------------
|
|
* ExecReScanWindowAgg
|
|
* -----------------
|
|
*/
|
|
void ExecReScanWindowAgg(WindowAggState* node)
|
|
{
|
|
ExprContext* econtext = node->ss.ps.ps_ExprContext;
|
|
|
|
node->all_done = false;
|
|
|
|
node->ss.ps.ps_TupFromTlist = false;
|
|
node->all_first = true;
|
|
|
|
/* release tuplestore et al */
|
|
release_partition(node);
|
|
|
|
/* release all temp tuples, but especially first_part_slot */
|
|
(void)ExecClearTuple(node->ss.ss_ScanTupleSlot);
|
|
(void)ExecClearTuple(node->first_part_slot);
|
|
(void)ExecClearTuple(node->agg_row_slot);
|
|
(void)ExecClearTuple(node->temp_slot_1);
|
|
(void)ExecClearTuple(node->temp_slot_2);
|
|
|
|
/* Forget current wfunc values */
|
|
errno_t rc = memset_s(econtext->ecxt_aggvalues, sizeof(Datum) * node->numfuncs, 0, sizeof(Datum) * node->numfuncs);
|
|
securec_check(rc, "", "");
|
|
rc = memset_s(econtext->ecxt_aggnulls, sizeof(bool) * node->numfuncs, 0, sizeof(bool) * node->numfuncs);
|
|
securec_check(rc, "", "");
|
|
|
|
/*
|
|
* if chgParam of subnode is not null then plan will be re-scanned by
|
|
* first ExecProcNode.
|
|
*/
|
|
if (node->ss.ps.lefttree->chgParam == NULL)
|
|
ExecReScan(node->ss.ps.lefttree);
|
|
}
|
|
|
|
/*
|
|
* initialize_peragg
|
|
*
|
|
* Almost same as in nodeAgg.c, except we don't support DISTINCT currently.
|
|
*/
|
|
WindowStatePerAggData* initialize_peragg(WindowAggState* winstate, WindowFunc* wfunc,
|
|
WindowStatePerAgg peraggstate)
|
|
{
|
|
Oid input_types[FUNC_MAX_ARGS];
|
|
int num_arguments;
|
|
HeapTuple agg_tuple;
|
|
Form_pg_aggregate aggform;
|
|
Oid agg_trans_type;
|
|
AclResult aclresult;
|
|
Oid transfn_oid, finalfn_oid;
|
|
Expr* transfnexpr = NULL;
|
|
Expr* finalfnexpr = NULL;
|
|
Datum text_initVal;
|
|
int i;
|
|
ListCell* lc = NULL;
|
|
|
|
num_arguments = list_length(wfunc->args);
|
|
|
|
i = 0;
|
|
foreach (lc, wfunc->args) {
|
|
input_types[i++] = exprType((Node*)lfirst(lc));
|
|
}
|
|
|
|
agg_tuple = SearchSysCache1(AGGFNOID, ObjectIdGetDatum(wfunc->winfnoid));
|
|
if (!HeapTupleIsValid(agg_tuple))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_CACHE_LOOKUP_FAILED),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("cache lookup failed for aggregate %u of WindowsAgg", wfunc->winfnoid)));
|
|
aggform = (Form_pg_aggregate)GETSTRUCT(agg_tuple);
|
|
|
|
/*
|
|
* ExecInitWindowAgg already checked permission to call aggregate function
|
|
* ... but we still need to check the component functions
|
|
*/
|
|
peraggstate->transfn_oid = transfn_oid = aggform->aggtransfn;
|
|
peraggstate->finalfn_oid = finalfn_oid = aggform->aggfinalfn;
|
|
|
|
/* Check that aggregate owner has permission to call component fns */
|
|
{
|
|
HeapTuple proc_tuple;
|
|
Oid agg_owner;
|
|
|
|
proc_tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(wfunc->winfnoid));
|
|
if (!HeapTupleIsValid(proc_tuple))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_CACHE_LOOKUP_FAILED),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("cache lookup failed for function %u of WindowsAgg in pg_proc", wfunc->winfnoid)));
|
|
agg_owner = ((Form_pg_proc)GETSTRUCT(proc_tuple))->proowner;
|
|
ReleaseSysCache(proc_tuple);
|
|
|
|
aclresult = pg_proc_aclcheck(transfn_oid, agg_owner, ACL_EXECUTE);
|
|
if (aclresult != ACLCHECK_OK)
|
|
aclcheck_error(aclresult, ACL_KIND_PROC, get_func_name(transfn_oid));
|
|
if (OidIsValid(finalfn_oid)) {
|
|
aclresult = pg_proc_aclcheck(finalfn_oid, agg_owner, ACL_EXECUTE);
|
|
if (aclresult != ACLCHECK_OK)
|
|
aclcheck_error(aclresult, ACL_KIND_PROC, get_func_name(finalfn_oid));
|
|
}
|
|
}
|
|
|
|
/* resolve actual type of transition state, if polymorphic */
|
|
agg_trans_type = resolve_aggregate_transtype(wfunc->winfnoid, aggform->aggtranstype, input_types, num_arguments);
|
|
|
|
/* build expression trees using actual argument & result types */
|
|
build_trans_aggregate_fnexprs(num_arguments,
|
|
0, /* no ordered-set window functions yet */
|
|
false,
|
|
false, /* no variadic window functions yet */
|
|
agg_trans_type,
|
|
input_types,
|
|
wfunc->wintype,
|
|
wfunc->inputcollid,
|
|
transfn_oid,
|
|
finalfn_oid,
|
|
&transfnexpr,
|
|
&finalfnexpr);
|
|
|
|
fmgr_info(transfn_oid, &peraggstate->transfn);
|
|
fmgr_info_set_expr((Node*)transfnexpr, &peraggstate->transfn);
|
|
|
|
if (OidIsValid(finalfn_oid)) {
|
|
fmgr_info(finalfn_oid, &peraggstate->finalfn);
|
|
fmgr_info_set_expr((Node*)finalfnexpr, &peraggstate->finalfn);
|
|
}
|
|
|
|
get_typlenbyval(wfunc->wintype, &peraggstate->resulttypeLen, &peraggstate->resulttypeByVal);
|
|
get_typlenbyval(agg_trans_type, &peraggstate->transtypeLen, &peraggstate->transtypeByVal);
|
|
|
|
/*
|
|
* initval is potentially null, so don't try to access it as a struct
|
|
* field. Must do it the hard way with SysCacheGetAttr.
|
|
*/
|
|
text_initVal = SysCacheGetAttr(AGGFNOID, agg_tuple, Anum_pg_aggregate_agginitval, &peraggstate->initValueIsNull);
|
|
|
|
if (peraggstate->initValueIsNull)
|
|
peraggstate->initValue = (Datum)0;
|
|
else
|
|
peraggstate->initValue = get_agg_init_val(text_initVal, agg_trans_type);
|
|
|
|
/*
|
|
* 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) {
|
|
if (num_arguments < 1 || !IsBinaryCoercible(input_types[0], agg_trans_type))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("aggregate %u needs to have compatible input type and transition type", wfunc->winfnoid)));
|
|
}
|
|
|
|
ReleaseSysCache(agg_tuple);
|
|
|
|
return peraggstate;
|
|
}
|
|
|
|
static Datum get_agg_init_val(Datum text_init_val, Oid transtype)
|
|
{
|
|
Oid typ_input, typ_io_param;
|
|
char* str_init_val = NULL;
|
|
Datum init_val;
|
|
|
|
getTypeInputInfo(transtype, &typ_input, &typ_io_param);
|
|
str_init_val = TextDatumGetCString(text_init_val);
|
|
init_val = OidInputFunctionCall(typ_input, str_init_val, typ_io_param, -1);
|
|
pfree_ext(str_init_val);
|
|
return init_val;
|
|
}
|
|
|
|
/*
|
|
* are_peers
|
|
* compare two rows to see if they are equal according to the ORDER BY clause
|
|
*
|
|
* NB: this does not consider the window frame mode.
|
|
*/
|
|
static bool are_peers(WindowAggState* winstate, TupleTableSlot* slot1, TupleTableSlot* slot2)
|
|
{
|
|
WindowAgg* node = (WindowAgg*)winstate->ss.ps.plan;
|
|
|
|
/* If no ORDER BY, all rows are peers with each other */
|
|
if (node->ordNumCols == 0)
|
|
return true;
|
|
|
|
return execTuplesMatch(slot1,
|
|
slot2,
|
|
node->ordNumCols,
|
|
node->ordColIdx,
|
|
winstate->ordEqfunctions,
|
|
winstate->tmpcontext->ecxt_per_tuple_memory);
|
|
}
|
|
|
|
/*
|
|
* window_gettupleslot
|
|
* Fetch the pos'th tuple of the current partition into the slot,
|
|
* using the winobj's read pointer
|
|
*
|
|
* Returns true if successful, false if no such row
|
|
*/
|
|
static bool window_gettupleslot(WindowObject winobj, int64 pos, TupleTableSlot* slot)
|
|
{
|
|
WindowAggState* winstate = winobj->winstate;
|
|
MemoryContext old_context;
|
|
|
|
/* Don't allow passing -1 to spool_tuples here */
|
|
if (pos < 0)
|
|
return false;
|
|
|
|
/* If necessary, fetch the tuple into the spool */
|
|
spool_tuples(winstate, pos);
|
|
|
|
if (pos >= winstate->spooled_rows)
|
|
return false;
|
|
|
|
if (pos < winobj->markpos)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FETCH_DATA_FAILED),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("cannot fetch row before WindowObject's mark position")));
|
|
|
|
old_context = MemoryContextSwitchTo(winstate->ss.ps.ps_ExprContext->ecxt_per_query_memory);
|
|
|
|
tuplestore_select_read_pointer(winstate->buffer, winobj->readptr);
|
|
|
|
/*
|
|
* There's no API to refetch the tuple at the current position. We have to
|
|
* move one tuple forward, and then one backward. (We don't do it the
|
|
* other way because we might try to fetch the row before our mark, which
|
|
* isn't allowed.) XXX this case could stand to be optimized.
|
|
*/
|
|
if (winobj->seekpos == pos) {
|
|
(void)tuplestore_advance(winstate->buffer, true);
|
|
winobj->seekpos++;
|
|
}
|
|
|
|
while (winobj->seekpos > pos) {
|
|
if (!tuplestore_gettupleslot(winstate->buffer, false, true, slot))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATA_EXCEPTION),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("cannot get result from tuplestore in WindowsAgg.")));
|
|
winobj->seekpos--;
|
|
}
|
|
|
|
while (winobj->seekpos < pos) {
|
|
if (!tuplestore_gettupleslot(winstate->buffer, true, true, slot))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATA_EXCEPTION),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("cannot get result from tuplestore in WindowsAgg.")));
|
|
winobj->seekpos++;
|
|
}
|
|
|
|
MemoryContextSwitchTo(old_context);
|
|
|
|
return true;
|
|
}
|
|
|
|
/***********************************************************************
|
|
* API exposed to window functions
|
|
***********************************************************************/
|
|
/*
|
|
* WinGetPartitionLocalMemory
|
|
* Get working memory that lives till end of partition processing
|
|
*
|
|
* On first call within a given partition, this allocates and zeroes the
|
|
* requested amount of space. Subsequent calls just return the same chunk.
|
|
*
|
|
* Memory obtained this way is normally used to hold state that should be
|
|
* automatically reset for each new partition. If a window function wants
|
|
* to hold state across the whole query, fcinfo->fn_extra can be used in the
|
|
* usual way for that.
|
|
*/
|
|
void* WinGetPartitionLocalMemory(WindowObject winobj, Size sz)
|
|
{
|
|
Assert(WindowObjectIsValid(winobj));
|
|
if (winobj->localmem == NULL)
|
|
winobj->localmem = MemoryContextAllocZero(winobj->winstate->partcontext, sz);
|
|
return winobj->localmem;
|
|
}
|
|
|
|
/*
|
|
* WinGetCurrentPosition
|
|
* Return the current row's position (counting from 0) within the current
|
|
* partition.
|
|
*/
|
|
int64 WinGetCurrentPosition(WindowObject winobj)
|
|
{
|
|
Assert(WindowObjectIsValid(winobj));
|
|
return winobj->winstate->currentpos;
|
|
}
|
|
|
|
/*
|
|
* WinGetPartitionRowCount
|
|
* Return total number of rows contained in the current partition.
|
|
*
|
|
* Note: this is a relatively expensive operation because it forces the
|
|
* whole partition to be "spooled" into the tuplestore at once. Once
|
|
* executed, however, additional calls within the same partition are cheap.
|
|
*/
|
|
int64 WinGetPartitionRowCount(WindowObject winobj)
|
|
{
|
|
Assert(WindowObjectIsValid(winobj));
|
|
spool_tuples(winobj->winstate, -1);
|
|
return winobj->winstate->spooled_rows;
|
|
}
|
|
|
|
/*
|
|
* WinSetMarkPosition
|
|
* Set the "mark" position for the window object, which is the oldest row
|
|
* number (counting from 0) it is allowed to fetch during all subsequent
|
|
* operations within the current partition.
|
|
*
|
|
* Window functions do not have to call this, but are encouraged to move the
|
|
* mark forward when possible to keep the tuplestore size down and prevent
|
|
* having to spill rows to disk.
|
|
*/
|
|
void WinSetMarkPosition(WindowObject winobj, int64 markpos)
|
|
{
|
|
WindowAggState* winstate = NULL;
|
|
|
|
Assert(WindowObjectIsValid(winobj));
|
|
winstate = winobj->winstate;
|
|
|
|
if (markpos < winobj->markpos)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("cannot move WindowObject's mark position backward")));
|
|
tuplestore_select_read_pointer(winstate->buffer, winobj->markptr);
|
|
while (markpos > winobj->markpos) {
|
|
(void)tuplestore_advance(winstate->buffer, true);
|
|
winobj->markpos++;
|
|
}
|
|
tuplestore_select_read_pointer(winstate->buffer, winobj->readptr);
|
|
while (markpos > winobj->seekpos) {
|
|
(void)tuplestore_advance(winstate->buffer, true);
|
|
winobj->seekpos++;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* WinRowsArePeers
|
|
* Compare two rows (specified by absolute position in window) to see
|
|
* if they are equal according to the ORDER BY clause.
|
|
*
|
|
* NB: this does not consider the window frame mode.
|
|
*/
|
|
bool WinRowsArePeers(WindowObject winobj, int64 pos1, int64 pos2)
|
|
{
|
|
WindowAggState* winstate = NULL;
|
|
WindowAgg* node = NULL;
|
|
TupleTableSlot* slot1 = NULL;
|
|
TupleTableSlot* slot2 = NULL;
|
|
bool res = false;
|
|
|
|
Assert(WindowObjectIsValid(winobj));
|
|
winstate = winobj->winstate;
|
|
node = (WindowAgg*)winstate->ss.ps.plan;
|
|
|
|
/* If no ORDER BY, all rows are peers; don't bother to fetch them */
|
|
if (node->ordNumCols == 0)
|
|
return true;
|
|
|
|
slot1 = winstate->temp_slot_1;
|
|
slot2 = winstate->temp_slot_2;
|
|
|
|
if (!window_gettupleslot(winobj, pos1, slot1))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATA_EXCEPTION),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("specified position is out of window: " INT64_FORMAT, pos1)));
|
|
|
|
if (!window_gettupleslot(winobj, pos2, slot2))
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_DATA_EXCEPTION),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("specified position is out of window: " INT64_FORMAT, pos2)));
|
|
|
|
res = are_peers(winstate, slot1, slot2);
|
|
|
|
(void)ExecClearTuple(slot1);
|
|
(void)ExecClearTuple(slot2);
|
|
|
|
return res;
|
|
}
|
|
|
|
/*
|
|
* WinGetFuncArgInPartition
|
|
* Evaluate a window function's argument expression on a specified
|
|
* row of the partition. The row is identified in lseek(2) style,
|
|
* i.e. relative to the current, first, or last row.
|
|
*
|
|
* argno: argument number to evaluate (counted from 0)
|
|
* relpos: signed rowcount offset from the seek position
|
|
* seektype: WINDOW_SEEK_CURRENT, WINDOW_SEEK_HEAD, or WINDOW_SEEK_TAIL
|
|
* set_mark: If the row is found and set_mark is true, the mark is moved to
|
|
* the row as a side-effect.
|
|
* isnull: output argument, receives isnull status of result
|
|
* isout: output argument, set to indicate whether target row position
|
|
* is out of partition (can pass NULL if caller doesn't care about this)
|
|
*
|
|
* Specifying a nonexistent row is not an error, it just causes a null result
|
|
* (plus setting *isout true, if isout isn't NULL).
|
|
*/
|
|
Datum WinGetFuncArgInPartition(
|
|
WindowObject winobj, int argno, int relpos, int seektype, bool set_mark, bool* isnull, bool* isout)
|
|
{
|
|
WindowAggState* winstate = NULL;
|
|
ExprContext* econtext = NULL;
|
|
TupleTableSlot* slot = NULL;
|
|
bool got_tuple = false;
|
|
int64 abs_pos;
|
|
|
|
Assert(WindowObjectIsValid(winobj));
|
|
winstate = winobj->winstate;
|
|
econtext = winstate->ss.ps.ps_ExprContext;
|
|
slot = winstate->temp_slot_1;
|
|
|
|
switch (seektype) {
|
|
case WINDOW_SEEK_CURRENT:
|
|
abs_pos = winstate->currentpos + relpos;
|
|
break;
|
|
case WINDOW_SEEK_HEAD:
|
|
abs_pos = relpos;
|
|
break;
|
|
case WINDOW_SEEK_TAIL:
|
|
spool_tuples(winstate, -1);
|
|
abs_pos = winstate->spooled_rows - 1 + relpos;
|
|
break;
|
|
default:
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("unrecognized window seek type: %d on a specified row of partition.", seektype)));
|
|
abs_pos = 0; /* keep compiler quiet */
|
|
break;
|
|
}
|
|
|
|
got_tuple = window_gettupleslot(winobj, abs_pos, slot);
|
|
if (!got_tuple) {
|
|
if (isout !=NULL)
|
|
*isout = true;
|
|
*isnull = true;
|
|
return (Datum)0;
|
|
} else {
|
|
if (isout != NULL)
|
|
*isout = false;
|
|
if (set_mark) {
|
|
int frameOptions = winstate->frameOptions;
|
|
int64 mark_pos = abs_pos;
|
|
|
|
/*
|
|
* In RANGE mode with a moving frame head, we must not let the
|
|
* mark advance past frameheadpos, since that row has to be
|
|
* fetchable during future update_frameheadpos calls.
|
|
*
|
|
* XXX it is very ugly to pollute window functions' marks with
|
|
* this consideration; it could for instance mask a logic bug that
|
|
* lets a window function fetch rows before what it had claimed
|
|
* was its mark. Perhaps use a separate mark for frame head
|
|
* probes?
|
|
*/
|
|
if ((frameOptions & FRAMEOPTION_RANGE) && !(frameOptions & FRAMEOPTION_START_UNBOUNDED_PRECEDING)) {
|
|
update_frameheadpos(winobj, winstate->temp_slot_2);
|
|
if (mark_pos > winstate->frameheadpos)
|
|
mark_pos = winstate->frameheadpos;
|
|
}
|
|
WinSetMarkPosition(winobj, mark_pos);
|
|
}
|
|
econtext->ecxt_outertuple = slot;
|
|
return ExecEvalExpr((ExprState*)list_nth(winobj->argstates, argno), econtext, isnull, NULL);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* WinGetFuncArgInFrame
|
|
* Evaluate a window function's argument expression on a specified
|
|
* row of the window frame. The row is identified in lseek(2) style,
|
|
* i.e. relative to the current, first, or last row.
|
|
*
|
|
* argno: argument number to evaluate (counted from 0)
|
|
* relpos: signed rowcount offset from the seek position
|
|
* seektype: WINDOW_SEEK_CURRENT, WINDOW_SEEK_HEAD, or WINDOW_SEEK_TAIL
|
|
* set_mark: If the row is found and set_mark is true, the mark is moved to
|
|
* the row as a side-effect.
|
|
* isnull: output argument, receives isnull status of result
|
|
* isout: output argument, set to indicate whether target row position
|
|
* is out of frame (can pass NULL if caller doesn't care about this)
|
|
*
|
|
* Specifying a nonexistent row is not an error, it just causes a null result
|
|
* (plus setting *isout true, if isout isn't NULL).
|
|
*/
|
|
Datum WinGetFuncArgInFrame(
|
|
WindowObject winobj, int argno, int relpos, int seektype, bool set_mark, bool* isnull, bool* isout)
|
|
{
|
|
WindowAggState* winstate = NULL;
|
|
ExprContext* econtext = NULL;
|
|
TupleTableSlot* slot = NULL;
|
|
bool got_tuple = false;
|
|
int64 abs_pos;
|
|
|
|
if (!(WindowObjectIsValid(winobj))) {
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_UNEXPECTED_NULL_VALUE),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("window object is invalid")));
|
|
}
|
|
|
|
winstate = winobj->winstate;
|
|
econtext = winstate->ss.ps.ps_ExprContext;
|
|
slot = winstate->temp_slot_1;
|
|
|
|
switch (seektype) {
|
|
case WINDOW_SEEK_CURRENT:
|
|
abs_pos = winstate->currentpos + relpos;
|
|
break;
|
|
case WINDOW_SEEK_HEAD:
|
|
update_frameheadpos(winobj, slot);
|
|
abs_pos = winstate->frameheadpos + relpos;
|
|
break;
|
|
case WINDOW_SEEK_TAIL:
|
|
update_frametailpos(winobj, slot);
|
|
abs_pos = winstate->frametailpos + relpos;
|
|
break;
|
|
default:
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("unrecognized window seek type: %d on a specified row of window frame", seektype)));
|
|
abs_pos = 0; /* keep compiler quiet */
|
|
break;
|
|
}
|
|
|
|
got_tuple = window_gettupleslot(winobj, abs_pos, slot);
|
|
if (got_tuple)
|
|
got_tuple = row_is_in_frame(winstate, abs_pos, slot);
|
|
|
|
if (!got_tuple) {
|
|
if (isout != NULL)
|
|
*isout = true;
|
|
*isnull = true;
|
|
return (Datum)0;
|
|
} else {
|
|
if (isout != NULL)
|
|
*isout = false;
|
|
if (set_mark) {
|
|
int frameOptions = winstate->frameOptions;
|
|
int64 mark_pos = abs_pos;
|
|
|
|
/*
|
|
* In RANGE mode with a moving frame head, we must not let the
|
|
* mark advance past frameheadpos, since that row has to be
|
|
* fetchable during future update_frameheadpos calls.
|
|
*
|
|
* XXX it is very ugly to pollute window functions' marks with
|
|
* this consideration; it could for instance mask a logic bug that
|
|
* lets a window function fetch rows before what it had claimed
|
|
* was its mark. Perhaps use a separate mark for frame head
|
|
* probes?
|
|
*/
|
|
if ((frameOptions & FRAMEOPTION_RANGE) && !(frameOptions & FRAMEOPTION_START_UNBOUNDED_PRECEDING)) {
|
|
update_frameheadpos(winobj, winstate->temp_slot_2);
|
|
if (mark_pos > winstate->frameheadpos)
|
|
mark_pos = winstate->frameheadpos;
|
|
}
|
|
WinSetMarkPosition(winobj, mark_pos);
|
|
}
|
|
econtext->ecxt_outertuple = slot;
|
|
return ExecEvalExpr((ExprState*)list_nth(winobj->argstates, argno), econtext, isnull, NULL);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* WinGetFuncArgCurrent
|
|
* Evaluate a window function's argument expression on the current row.
|
|
*
|
|
* argno: argument number to evaluate (counted from 0)
|
|
* isnull: output argument, receives isnull status of result
|
|
*
|
|
* Note: this isn't quite equivalent to WinGetFuncArgInPartition or
|
|
* WinGetFuncArgInFrame targeting the current row, because it will succeed
|
|
* even if the WindowObject's mark has been set beyond the current row.
|
|
* This should generally be used for "ordinary" arguments of a window
|
|
* function, such as the offset argument of lead() or lag().
|
|
*/
|
|
Datum WinGetFuncArgCurrent(WindowObject winobj, int argno, bool* isnull)
|
|
{
|
|
WindowAggState* winstate = NULL;
|
|
ExprContext* econtext = NULL;
|
|
|
|
if (!(WindowObjectIsValid(winobj))) {
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_UNEXPECTED_NULL_VALUE),
|
|
errmodule(MOD_EXECUTOR),
|
|
errmsg("window object is invalid")));
|
|
}
|
|
winstate = winobj->winstate;
|
|
|
|
econtext = winstate->ss.ps.ps_ExprContext;
|
|
|
|
econtext->ecxt_outertuple = winstate->ss.ss_ScanTupleSlot;
|
|
return ExecEvalExpr((ExprState*)list_nth(winobj->argstates, argno), econtext, isnull, NULL);
|
|
}
|