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postgresql/src/backend/executor/execProcnode.c

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/*-------------------------------------------------------------------------
*
* execProcnode.c
* contains dispatch functions which call the appropriate "initialize",
* "get a tuple", and "cleanup" routines for the given node type.
* If the node has children, then it will presumably call ExecInitNode,
* ExecProcNode, or ExecEndNode on its subnodes and do the appropriate
* processing..
*
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/execProcnode.c,v 1.18 2000/01/26 05:56:21 momjian Exp $
*
*-------------------------------------------------------------------------
*/
/*
* INTERFACE ROUTINES
* ExecInitNode - initialize a plan node and its subplans
* ExecProcNode - get a tuple by executing the plan node
* ExecEndNode - shut down a plan node and its subplans
*
* NOTES
* This used to be three files. It is now all combined into
* one file so that it is easier to keep ExecInitNode, ExecProcNode,
* and ExecEndNode in sync when new nodes are added.
*
* EXAMPLE
* suppose we want the age of the manager of the shoe department and
* the number of employees in that department. so we have the query:
*
* retrieve (DEPT.no_emps, EMP.age)
* where EMP.name = DEPT.mgr and
* DEPT.name = "shoe"
*
* Suppose the planner gives us the following plan:
*
* Nest Loop (DEPT.mgr = EMP.name)
* / \
* / \
* Seq Scan Seq Scan
* DEPT EMP
* (name = "shoe")
*
* ExecStart() is called first.
* It calls InitPlan() which calls ExecInitNode() on
* the root of the plan -- the nest loop node.
*
* * ExecInitNode() notices that it is looking at a nest loop and
* as the code below demonstrates, it calls ExecInitNestLoop().
* Eventually this calls ExecInitNode() on the right and left subplans
* and so forth until the entire plan is initialized.
*
* * Then when ExecRun() is called, it calls ExecutePlan() which
* calls ExecProcNode() repeatedly on the top node of the plan.
* Each time this happens, ExecProcNode() will end up calling
* ExecNestLoop(), which calls ExecProcNode() on its subplans.
* Each of these subplans is a sequential scan so ExecSeqScan() is
* called. The slots returned by ExecSeqScan() may contain
* tuples which contain the attributes ExecNestLoop() uses to
* form the tuples it returns.
*
* * Eventually ExecSeqScan() stops returning tuples and the nest
* loop join ends. Lastly, ExecEnd() calls ExecEndNode() which
* calls ExecEndNestLoop() which in turn calls ExecEndNode() on
* its subplans which result in ExecEndSeqScan().
*
* This should show how the executor works by having
* ExecInitNode(), ExecProcNode() and ExecEndNode() dispatch
* their work to the appopriate node support routines which may
* in turn call these routines themselves on their subplans.
*
*/
#include "postgres.h"
#include "executor/executor.h"
#include "executor/nodeAgg.h"
#include "executor/nodeAppend.h"
#include "executor/nodeGroup.h"
#include "executor/nodeHash.h"
#include "executor/nodeHashjoin.h"
#include "executor/nodeIndexscan.h"
#include "executor/nodeTidscan.h"
#include "executor/nodeMaterial.h"
#include "executor/nodeMergejoin.h"
#include "executor/nodeNestloop.h"
#include "executor/nodeResult.h"
#include "executor/nodeSeqscan.h"
#include "executor/nodeSort.h"
#include "executor/nodeSubplan.h"
#include "executor/nodeUnique.h"
#include "miscadmin.h"
#include "tcop/tcopprot.h"
/* ------------------------------------------------------------------------
* ExecInitNode
*
* Recursively initializes all the nodes in the plan rooted
* at 'node'.
*
* Initial States:
* 'node' is the plan produced by the query planner
*
* returns TRUE/FALSE on whether the plan was successfully initialized
* ------------------------------------------------------------------------
*/
bool
ExecInitNode(Plan *node, EState *estate, Plan *parent)
{
bool result;
List *subp;
/* ----------------
* do nothing when we get to the end
* of a leaf on tree.
* ----------------
*/
if (node == NULL)
return FALSE;
foreach(subp, node->initPlan)
{
result = ExecInitSubPlan((SubPlan *) lfirst(subp), estate, node);
if (result == FALSE)
return FALSE;
}
switch (nodeTag(node))
{
/* ----------------
* control nodes
* ----------------
*/
case T_Result:
result = ExecInitResult((Result *) node, estate, parent);
break;
case T_Append:
result = ExecInitAppend((Append *) node, estate, parent);
break;
/* ----------------
* scan nodes
* ----------------
*/
case T_SeqScan:
result = ExecInitSeqScan((SeqScan *) node, estate, parent);
break;
case T_IndexScan:
result = ExecInitIndexScan((IndexScan *) node, estate, parent);
break;
/* ----------------
* join nodes
* ----------------
*/
case T_NestLoop:
result = ExecInitNestLoop((NestLoop *) node, estate, parent);
break;
case T_MergeJoin:
result = ExecInitMergeJoin((MergeJoin *) node, estate, parent);
break;
/* ----------------
* materialization nodes
* ----------------
*/
case T_Material:
result = ExecInitMaterial((Material *) node, estate, parent);
break;
case T_Sort:
result = ExecInitSort((Sort *) node, estate, parent);
break;
case T_Unique:
result = ExecInitUnique((Unique *) node, estate, parent);
break;
case T_Group:
result = ExecInitGroup((Group *) node, estate, parent);
break;
case T_Agg:
result = ExecInitAgg((Agg *) node, estate, parent);
break;
case T_Hash:
result = ExecInitHash((Hash *) node, estate, parent);
break;
case T_HashJoin:
result = ExecInitHashJoin((HashJoin *) node, estate, parent);
break;
case T_TidScan:
result = ExecInitTidScan((TidScan *) node, estate, parent);
break;
default:
elog(ERROR, "ExecInitNode: node %d unsupported", nodeTag(node));
result = FALSE;
}
if (result != FALSE)
{
foreach(subp, node->subPlan)
{
result = ExecInitSubPlan((SubPlan *) lfirst(subp), estate, node);
if (result == FALSE)
return FALSE;
}
}
return result;
}
/* ----------------------------------------------------------------
* ExecProcNode
*
* Initial States:
* the query tree must be initialized once by calling ExecInit.
* ----------------------------------------------------------------
*/
TupleTableSlot *
ExecProcNode(Plan *node, Plan *parent)
{
TupleTableSlot *result;
/* ----------------
* deal with NULL nodes..
* ----------------
*/
if (QueryCancel)
CancelQuery();
if (node == NULL)
return NULL;
if (node->chgParam != NULL) /* something changed */
ExecReScan(node, NULL, parent); /* let ReScan handle this */
switch (nodeTag(node))
{
/* ----------------
* control nodes
* ----------------
*/
case T_Result:
result = ExecResult((Result *) node);
break;
case T_Append:
result = ExecProcAppend((Append *) node);
break;
/* ----------------
* scan nodes
* ----------------
*/
case T_SeqScan:
result = ExecSeqScan((SeqScan *) node);
break;
case T_IndexScan:
result = ExecIndexScan((IndexScan *) node);
break;
/* ----------------
* join nodes
* ----------------
*/
case T_NestLoop:
result = ExecNestLoop((NestLoop *) node, parent);
break;
case T_MergeJoin:
result = ExecMergeJoin((MergeJoin *) node);
break;
/* ----------------
* materialization nodes
* ----------------
*/
case T_Material:
result = ExecMaterial((Material *) node);
break;
case T_Sort:
result = ExecSort((Sort *) node);
break;
case T_Unique:
result = ExecUnique((Unique *) node);
break;
case T_Group:
result = ExecGroup((Group *) node);
break;
case T_Agg:
result = ExecAgg((Agg *) node);
break;
case T_Hash:
result = ExecHash((Hash *) node);
break;
case T_HashJoin:
result = ExecHashJoin((HashJoin *) node);
break;
case T_TidScan:
result = ExecTidScan((TidScan *) node);
break;
default:
elog(ERROR, "ExecProcNode: node %d unsupported", nodeTag(node));
result = NULL;
}
return result;
}
int
ExecCountSlotsNode(Plan *node)
{
if (node == (Plan *) NULL)
return 0;
switch (nodeTag(node))
{
/* ----------------
* control nodes
* ----------------
*/
case T_Result:
return ExecCountSlotsResult((Result *) node);
case T_Append:
return ExecCountSlotsAppend((Append *) node);
/* ----------------
* scan nodes
* ----------------
*/
case T_SeqScan:
return ExecCountSlotsSeqScan((SeqScan *) node);
case T_IndexScan:
return ExecCountSlotsIndexScan((IndexScan *) node);
/* ----------------
* join nodes
* ----------------
*/
case T_NestLoop:
return ExecCountSlotsNestLoop((NestLoop *) node);
case T_MergeJoin:
return ExecCountSlotsMergeJoin((MergeJoin *) node);
/* ----------------
* materialization nodes
* ----------------
*/
case T_Material:
return ExecCountSlotsMaterial((Material *) node);
case T_Sort:
return ExecCountSlotsSort((Sort *) node);
case T_Unique:
return ExecCountSlotsUnique((Unique *) node);
case T_Group:
return ExecCountSlotsGroup((Group *) node);
case T_Agg:
return ExecCountSlotsAgg((Agg *) node);
case T_Hash:
return ExecCountSlotsHash((Hash *) node);
case T_HashJoin:
return ExecCountSlotsHashJoin((HashJoin *) node);
case T_TidScan:
return ExecCountSlotsTidScan((TidScan *) node);
default:
elog(ERROR, "ExecCountSlotsNode: node not yet supported: %d",
nodeTag(node));
break;
}
return 0;
}
/* ----------------------------------------------------------------
* ExecEndNode
*
* Recursively cleans up all the nodes in the plan rooted
* at 'node'.
*
* After this operation, the query plan will not be able to
* processed any further. This should be called only after
* the query plan has been fully executed.
* ----------------------------------------------------------------
*/
void
ExecEndNode(Plan *node, Plan *parent)
{
List *subp;
/* ----------------
* do nothing when we get to the end
* of a leaf on tree.
* ----------------
*/
if (node == NULL)
return;
foreach(subp, node->initPlan)
ExecEndSubPlan((SubPlan *) lfirst(subp));
foreach(subp, node->subPlan)
ExecEndSubPlan((SubPlan *) lfirst(subp));
if (node->chgParam != NULL)
{
freeList(node->chgParam);
node->chgParam = NULL;
}
switch (nodeTag(node))
{
/* ----------------
* control nodes
* ----------------
*/
case T_Result:
ExecEndResult((Result *) node);
break;
case T_Append:
ExecEndAppend((Append *) node);
break;
/* ----------------
* scan nodes
* ----------------
*/
case T_SeqScan:
ExecEndSeqScan((SeqScan *) node);
break;
case T_IndexScan:
ExecEndIndexScan((IndexScan *) node);
break;
/* ----------------
* join nodes
* ----------------
*/
case T_NestLoop:
ExecEndNestLoop((NestLoop *) node);
break;
case T_MergeJoin:
ExecEndMergeJoin((MergeJoin *) node);
break;
/* ----------------
* materialization nodes
* ----------------
*/
case T_Material:
ExecEndMaterial((Material *) node);
break;
case T_Sort:
ExecEndSort((Sort *) node);
break;
case T_Unique:
ExecEndUnique((Unique *) node);
break;
case T_Group:
ExecEndGroup((Group *) node);
break;
case T_Agg:
ExecEndAgg((Agg *) node);
break;
/* ----------------
* XXX add hooks to these
* ----------------
*/
case T_Hash:
ExecEndHash((Hash *) node);
break;
case T_HashJoin:
ExecEndHashJoin((HashJoin *) node);
break;
case T_TidScan:
ExecEndTidScan((TidScan *) node);
break;
default:
elog(ERROR, "ExecEndNode: node %d unsupported", nodeTag(node));
break;
}
}
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