greenplumn planshare 源码
greenplumn planshare 代码
文件路径：/src/backend/optimizer/plan/planshare.c
/*-------------------------------------------------------------------------
*
* planshare.c
* Plan shared plan
*
* Portions Copyright (c) 2007-2008, Greenplum inc
* Portions Copyright (c) 2012-Present VMware, Inc. or its affiliates.
*
*
* IDENTIFICATION
* src/backend/optimizer/plan/planshare.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "optimizer/clauses.h"
#include "optimizer/cost.h"
#include "optimizer/pathnode.h"
#include "optimizer/paths.h"
#include "optimizer/planmain.h"
#include "optimizer/subselect.h"
#include "optimizer/planshare.h"
static ShareInputScan *
make_shareinputscan(PlannerInfo *root, Plan *inputplan)
{
ShareInputScan *sisc;
Path sipath;
sisc = makeNode(ShareInputScan);
sisc->scan.plan.targetlist = copyObject(inputplan->targetlist);
sisc->scan.plan.lefttree = inputplan;
sisc->scan.plan.flow = copyObject(inputplan->flow);
sisc->cross_slice = false;
sisc->producer_slice_id = -1;
sisc->this_slice_id = -1;
sisc->nconsumers = 0;
sisc->discard_output = false;
sisc->scan.plan.qual = NIL;
sisc->scan.plan.righttree = NULL;
cost_shareinputscan(&sipath, root, inputplan->total_cost, inputplan->plan_rows, inputplan->plan_width);
sisc->scan.plan.startup_cost = sipath.startup_cost;
sisc->scan.plan.total_cost = sipath.total_cost;
sisc->scan.plan.plan_rows = inputplan->plan_rows;
sisc->scan.plan.plan_width = inputplan->plan_width;
return sisc;
}
/*
* Prepare a subplan for sharing. After this, you can call
* share_prepared_plan() as many times as you want to share this plan.
*
* This doesn't do much at the moment. One little optimization is that
* if the subplan is a ShareInputScan, we make the new ShareInputScans
* be siblings of that, rather than creating a ShareInputScan on
* top of a ShareInputScan.
*/
Plan *
prepare_plan_for_sharing(PlannerInfo *root, Plan *common)
{
Plan *shared = common;
if (IsA(common, ShareInputScan))
{
shared = common->lefttree;
}
return shared;
}
/*
* Create a ShareInputScan to scan the given subplan. The subplan
* must've been prepared for sharing by calling
* prepare_plan_for_sharing().
*/
Plan *
share_prepared_plan(PlannerInfo *root, Plan *common)
{
return (Plan *) make_shareinputscan(root, common);
}
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