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/* ------------------------------------------------------------------------
*
* nodeCustom.c
* Routines to handle execution of custom scan node
*
* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* ------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/parallel.h"
#include "executor/executor.h"
#include "executor/nodeCustom.h"
#include "miscadmin.h"
#include "nodes/execnodes.h"
#include "nodes/extensible.h"
#include "nodes/plannodes.h"
#include "parser/parsetree.h"
#include "utils/hsearch.h"
#include "utils/memutils.h"
#include "utils/rel.h"
static TupleTableSlot *ExecCustomScan(PlanState *pstate);
CustomScanState *
ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
{
CustomScanState *css;
Relation scan_rel = NULL;
Index scanrelid = cscan->scan.scanrelid;
Index tlistvarno;
/*
* Allocate the CustomScanState object. We let the custom scan provider
* do the palloc, in case it wants to make a larger object that embeds
* CustomScanState as the first field. It must set the node tag and the
* methods field correctly at this time. Other standard fields should be
* set to zero.
*/
css = castNode(CustomScanState,
cscan->methods->CreateCustomScanState(cscan));
/* ensure flags is filled correctly */
css->flags = cscan->flags;
/* fill up fields of ScanState */
css->ss.ps.plan = &cscan->scan.plan;
css->ss.ps.state = estate;
css->ss.ps.ExecProcNode = ExecCustomScan;
/* create expression context for node */
ExecAssignExprContext(estate, &css->ss.ps);
/*
* open the scan relation, if any
*/
if (scanrelid > 0)
{
scan_rel = ExecOpenScanRelation(estate, scanrelid, eflags);
css->ss.ss_currentRelation = scan_rel;
}
/*
* Determine the scan tuple type. If the custom scan provider provided a
* targetlist describing the scan tuples, use that; else use base
* relation's rowtype.
*/
if (cscan->custom_scan_tlist != NIL || scan_rel == NULL)
{
TupleDesc scan_tupdesc;
scan_tupdesc = ExecTypeFromTL(cscan->custom_scan_tlist);
ExecInitScanTupleSlot(estate, &css->ss, scan_tupdesc, &TTSOpsVirtual);
/* Node's targetlist will contain Vars with varno = INDEX_VAR */
tlistvarno = INDEX_VAR;
}
else
{
ExecInitScanTupleSlot(estate, &css->ss, RelationGetDescr(scan_rel),
&TTSOpsVirtual);
/* Node's targetlist will contain Vars with varno = scanrelid */
tlistvarno = scanrelid;
}
/*
* Initialize result slot, type and projection.
*/
ExecInitResultTupleSlotTL(&css->ss.ps, &TTSOpsVirtual);
ExecAssignScanProjectionInfoWithVarno(&css->ss, tlistvarno);
/* initialize child expressions */
css->ss.ps.qual =
ExecInitQual(cscan->scan.plan.qual, (PlanState *) css);
/*
* The callback of custom-scan provider applies the final initialization
* of the custom-scan-state node according to its logic.
*/
css->methods->BeginCustomScan(css, estate, eflags);
return css;
}
static TupleTableSlot *
ExecCustomScan(PlanState *pstate)
{
CustomScanState *node = castNode(CustomScanState, pstate);
CHECK_FOR_INTERRUPTS();
Assert(node->methods->ExecCustomScan != NULL);
return node->methods->ExecCustomScan(node);
}
void
ExecEndCustomScan(CustomScanState *node)
{
Assert(node->methods->EndCustomScan != NULL);
node->methods->EndCustomScan(node);
/* Free the exprcontext */
ExecFreeExprContext(&node->ss.ps);
/* Clean out the tuple table */
ExecClearTuple(node->ss.ps.ps_ResultTupleSlot);
ExecClearTuple(node->ss.ss_ScanTupleSlot);
}
void
ExecReScanCustomScan(CustomScanState *node)
{
Assert(node->methods->ReScanCustomScan != NULL);
node->methods->ReScanCustomScan(node);
}
void
ExecCustomMarkPos(CustomScanState *node)
{
if (!node->methods->MarkPosCustomScan)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("custom scan \"%s\" does not support MarkPos",
node->methods->CustomName)));
node->methods->MarkPosCustomScan(node);
}
void
ExecCustomRestrPos(CustomScanState *node)
{
if (!node->methods->RestrPosCustomScan)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("custom scan \"%s\" does not support MarkPos",
node->methods->CustomName)));
node->methods->RestrPosCustomScan(node);
}
void
ExecCustomScanEstimate(CustomScanState *node, ParallelContext *pcxt)
{
const CustomExecMethods *methods = node->methods;
if (methods->EstimateDSMCustomScan)
{
node->pscan_len = methods->EstimateDSMCustomScan(node, pcxt);
shm_toc_estimate_chunk(&pcxt->estimator, node->pscan_len);
shm_toc_estimate_keys(&pcxt->estimator, 1);
}
}
void
ExecCustomScanInitializeDSM(CustomScanState *node, ParallelContext *pcxt)
{
const CustomExecMethods *methods = node->methods;
if (methods->InitializeDSMCustomScan)
{
int plan_node_id = node->ss.ps.plan->plan_node_id;
void *coordinate;
coordinate = shm_toc_allocate(pcxt->toc, node->pscan_len);
methods->InitializeDSMCustomScan(node, pcxt, coordinate);
shm_toc_insert(pcxt->toc, plan_node_id, coordinate);
}
}
void
ExecCustomScanReInitializeDSM(CustomScanState *node, ParallelContext *pcxt)
{
const CustomExecMethods *methods = node->methods;
if (methods->ReInitializeDSMCustomScan)
{
int plan_node_id = node->ss.ps.plan->plan_node_id;
void *coordinate;
coordinate = shm_toc_lookup(pcxt->toc, plan_node_id, false);
methods->ReInitializeDSMCustomScan(node, pcxt, coordinate);
}
}
void
ExecCustomScanInitializeWorker(CustomScanState *node,
ParallelWorkerContext *pwcxt)
{
const CustomExecMethods *methods = node->methods;
if (methods->InitializeWorkerCustomScan)
{
int plan_node_id = node->ss.ps.plan->plan_node_id;
void *coordinate;
coordinate = shm_toc_lookup(pwcxt->toc, plan_node_id, false);
methods->InitializeWorkerCustomScan(node, pwcxt->toc, coordinate);
}
}
void
ExecShutdownCustomScan(CustomScanState *node)
{
const CustomExecMethods *methods = node->methods;
if (methods->ShutdownCustomScan)
methods->ShutdownCustomScan(node);
}
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