/*-------------------------------------------------------------------------
*
* 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) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/execProcnode.c,v 1.34 2002/12/14 00:17:50 tgl Exp $
*
*-------------------------------------------------------------------------
*/
/*
* INTERFACE ROUTINES
* ExecCountSlotsNode - count tuple slots needed by plan tree
* 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
* ExecGetTupType - get result tuple type of a plan node
*
* 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. The result
* of ExecInitNode() is a plan state tree built with the same structure
* as the underlying plan tree.
*
* * Then when ExecRun() is called, it calls ExecutePlan() which calls
* ExecProcNode() repeatedly on the top node of the plan state tree.
* 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/instrument.h"
#include "executor/nodeAgg.h"
#include "executor/nodeAppend.h"
#include "executor/nodeFunctionscan.h"
#include "executor/nodeGroup.h"
#include "executor/nodeHash.h"
#include "executor/nodeHashjoin.h"
#include "executor/nodeIndexscan.h"
#include "executor/nodeLimit.h"
#include "executor/nodeMaterial.h"
#include "executor/nodeMergejoin.h"
#include "executor/nodeNestloop.h"
#include "executor/nodeResult.h"
#include "executor/nodeSeqscan.h"
#include "executor/nodeSetOp.h"
#include "executor/nodeSort.h"
#include "executor/nodeSubplan.h"
#include "executor/nodeSubqueryscan.h"
#include "executor/nodeTidscan.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
* 'estate' is the shared execution state for the query tree
*
* Returns a PlanState node corresponding to the given Plan node.
* ------------------------------------------------------------------------
*/
PlanState *
ExecInitNode(Plan *node, EState *estate)
{
PlanState *result;
List *subps;
List *subp;
/*
* do nothing when we get to the end of a leaf on tree.
*/
if (node == NULL)
return NULL;
switch (nodeTag(node))
{
/*
* control nodes
*/
case T_Result:
result = (PlanState *) ExecInitResult((Result *) node, estate);
break;
case T_Append:
result = (PlanState *) ExecInitAppend((Append *) node, estate);
break;
/*
* scan nodes
*/
case T_SeqScan:
result = (PlanState *) ExecInitSeqScan((SeqScan *) node, estate);
break;
case T_IndexScan:
result = (PlanState *) ExecInitIndexScan((IndexScan *) node, estate);
break;
case T_TidScan:
result = (PlanState *) ExecInitTidScan((TidScan *) node, estate);
break;
case T_SubqueryScan:
result = (PlanState *) ExecInitSubqueryScan((SubqueryScan *) node, estate);
break;
case T_FunctionScan:
result = (PlanState *) ExecInitFunctionScan((FunctionScan *) node, estate);
break;
/*
* join nodes
*/
case T_NestLoop:
result = (PlanState *) ExecInitNestLoop((NestLoop *) node, estate);
break;
case T_MergeJoin:
result = (PlanState *) ExecInitMergeJoin((MergeJoin *) node, estate);
break;
case T_HashJoin:
result = (PlanState *) ExecInitHashJoin((HashJoin *) node, estate);
break;
/*
* materialization nodes
*/
case T_Material:
result = (PlanState *) ExecInitMaterial((Material *) node, estate);
break;
case T_Sort:
result = (PlanState *) ExecInitSort((Sort *) node, estate);
break;
case T_Group:
result = (PlanState *) ExecInitGroup((Group *) node, estate);
break;
case T_Agg:
result = (PlanState *) ExecInitAgg((Agg *) node, estate);
break;
case T_Unique:
result = (PlanState *) ExecInitUnique((Unique *) node, estate);
break;
case T_Hash:
result = (PlanState *) ExecInitHash((Hash *) node, estate);
break;
case T_SetOp:
result = (PlanState *) ExecInitSetOp((SetOp *) node, estate);
break;
case T_Limit:
result = (PlanState *) ExecInitLimit((Limit *) node, estate);
break;
default:
elog(ERROR, "ExecInitNode: node type %d unsupported",
(int) nodeTag(node));
result = NULL; /* keep compiler quiet */
break;
}
/*
* Initialize any initPlans present in this node. The planner put
* them in a separate list for us.
*/
subps = NIL;
foreach(subp, node->initPlan)
{
SubPlan *subplan = (SubPlan *) lfirst(subp);
SubPlanState *sstate;
Assert(IsA(subplan, SubPlan));
sstate = ExecInitExprInitPlan(subplan, result);
ExecInitSubPlan(sstate, estate);
subps = lappend(subps, sstate);
}
result->initPlan = subps;
/*
* Initialize any subPlans present in this node. These were found
* by ExecInitExpr during initialization of the PlanState. Note we
* must do this after initializing initPlans, in case their arguments
* contain subPlans (is that actually possible? perhaps not).
*/
subps = NIL;
foreach(subp, result->subPlan)
{
SubPlanState *sstate = (SubPlanState *) lfirst(subp);
Assert(IsA(sstate, SubPlanState));
ExecInitSubPlan(sstate, estate);
subps = lappend(subps, sstate);
}
result->subPlan = subps;
/* Set up instrumentation for this node if requested */
if (estate->es_instrument)
result->instrument = InstrAlloc();
return result;
}
/* ----------------------------------------------------------------
* ExecProcNode
*
* Execute the given node to return a(nother) tuple.
* ----------------------------------------------------------------
*/
TupleTableSlot *
ExecProcNode(PlanState *node)
{
TupleTableSlot *result;
CHECK_FOR_INTERRUPTS();
/*
* deal with NULL nodes..
*/
if (node == NULL)
return NULL;
if (node->chgParam != NIL) /* something changed */
ExecReScan(node, NULL); /* let ReScan handle this */
if (node->instrument)
InstrStartNode(node->instrument);
switch (nodeTag(node))
{
/*
* control nodes
*/
case T_ResultState:
result = ExecResult((ResultState *) node);
break;
case T_AppendState:
result = ExecProcAppend((AppendState *) node);
break;
/*
* scan nodes
*/
case T_SeqScanState:
result = ExecSeqScan((SeqScanState *) node);
break;
case T_IndexScanState:
result = ExecIndexScan((IndexScanState *) node);
break;
case T_TidScanState:
result = ExecTidScan((TidScanState *) node);
break;
case T_SubqueryScanState:
result = ExecSubqueryScan((SubqueryScanState *) node);
break;
case T_FunctionScanState:
result = ExecFunctionScan((FunctionScanState *) node);
break;
/*
* join nodes
*/
case T_NestLoopState:
result = ExecNestLoop((NestLoopState *) node);
break;
case T_MergeJoinState:
result = ExecMergeJoin((MergeJoinState *) node);
break;
case T_HashJoinState:
result = ExecHashJoin((HashJoinState *) node);
break;
/*
* materialization nodes
*/
case T_MaterialState:
result = ExecMaterial((MaterialState *) node);
break;
case T_SortState:
result = ExecSort((SortState *) node);
break;
case T_GroupState:
result = ExecGroup((GroupState *) node);
break;
case T_AggState:
result = ExecAgg((AggState *) node);
break;
case T_UniqueState:
result = ExecUnique((UniqueState *) node);
break;
case T_HashState:
result = ExecHash((HashState *) node);
break;
case T_SetOpState:
result = ExecSetOp((SetOpState *) node);
break;
case T_LimitState:
result = ExecLimit((LimitState *) node);
break;
default:
elog(ERROR, "ExecProcNode: node type %d unsupported",
(int) nodeTag(node));
result = NULL;
break;
}
if (node->instrument)
InstrStopNode(node->instrument, !TupIsNull(result));
return result;
}
/*
* ExecCountSlotsNode - count up the number of tuple table slots needed
*
* Note that this scans a Plan tree, not a PlanState tree, because we
* haven't built the PlanState tree yet ...
*/
int
ExecCountSlotsNode(Plan *node)
{
if (node == 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);
case T_TidScan:
return ExecCountSlotsTidScan((TidScan *) node);
case T_SubqueryScan:
return ExecCountSlotsSubqueryScan((SubqueryScan *) node);
case T_FunctionScan:
return ExecCountSlotsFunctionScan((FunctionScan *) node);
/*
* join nodes
*/
case T_NestLoop:
return ExecCountSlotsNestLoop((NestLoop *) node);
case T_MergeJoin:
return ExecCountSlotsMergeJoin((MergeJoin *) node);
case T_HashJoin:
return ExecCountSlotsHashJoin((HashJoin *) node);
/*
* materialization nodes
*/
case T_Material:
return ExecCountSlotsMaterial((Material *) node);
case T_Sort:
return ExecCountSlotsSort((Sort *) node);
case T_Group:
return ExecCountSlotsGroup((Group *) node);
case T_Agg:
return ExecCountSlotsAgg((Agg *) node);
case T_Unique:
return ExecCountSlotsUnique((Unique *) node);
case T_Hash:
return ExecCountSlotsHash((Hash *) node);
case T_SetOp:
return ExecCountSlotsSetOp((SetOp *) node);
case T_Limit:
return ExecCountSlotsLimit((Limit *) node);
default:
elog(ERROR, "ExecCountSlotsNode: node type %d unsupported",
(int) 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(PlanState *node)
{
List *subp;
/*
* do nothing when we get to the end of a leaf on tree.
*/
if (node == NULL)
return;
/* Clean up initPlans and subPlans */
foreach(subp, node->initPlan)
ExecEndSubPlan((SubPlanState *) lfirst(subp));
foreach(subp, node->subPlan)
ExecEndSubPlan((SubPlanState *) lfirst(subp));
if (node->chgParam != NIL)
{
freeList(node->chgParam);
node->chgParam = NIL;
}
switch (nodeTag(node))
{
/*
* control nodes
*/
case T_ResultState:
ExecEndResult((ResultState *) node);
break;
case T_AppendState:
ExecEndAppend((AppendState *) node);
break;
/*
* scan nodes
*/
case T_SeqScanState:
ExecEndSeqScan((SeqScanState *) node);
break;
case T_IndexScanState:
ExecEndIndexScan((IndexScanState *) node);
break;
case T_TidScanState:
ExecEndTidScan((TidScanState *) node);
break;
case T_SubqueryScanState:
ExecEndSubqueryScan((SubqueryScanState *) node);
break;
case T_FunctionScanState:
ExecEndFunctionScan((FunctionScanState *) node);
break;
/*
* join nodes
*/
case T_NestLoopState:
ExecEndNestLoop((NestLoopState *) node);
break;
case T_MergeJoinState:
ExecEndMergeJoin((MergeJoinState *) node);
break;
case T_HashJoinState:
ExecEndHashJoin((HashJoinState *) node);
break;
/*
* materialization nodes
*/
case T_MaterialState:
ExecEndMaterial((MaterialState *) node);
break;
case T_SortState:
ExecEndSort((SortState *) node);
break;
case T_GroupState:
ExecEndGroup((GroupState *) node);
break;
case T_AggState:
ExecEndAgg((AggState *) node);
break;
case T_UniqueState:
ExecEndUnique((UniqueState *) node);
break;
case T_HashState:
ExecEndHash((HashState *) node);
break;
case T_SetOpState:
ExecEndSetOp((SetOpState *) node);
break;
case T_LimitState:
ExecEndLimit((LimitState *) node);
break;
default:
elog(ERROR, "ExecEndNode: node type %d unsupported",
(int) nodeTag(node));
break;
}
}
/* ----------------------------------------------------------------
* ExecGetTupType
*
* this gives you the tuple descriptor for tuples returned
* by this node. I really wish I could ditch this routine,
* but since not all nodes store their type info in the same
* place, we have to do something special for each node type.
*
* ----------------------------------------------------------------
*/
TupleDesc
ExecGetTupType(PlanState *node)
{
TupleTableSlot *slot;
if (node == NULL)
return NULL;
switch (nodeTag(node))
{
case T_ResultState:
{
ResultState *resstate = (ResultState *) node;
slot = resstate->ps.ps_ResultTupleSlot;
}
break;
case T_AppendState:
{
AppendState *appendstate = (AppendState *) node;
slot = appendstate->ps.ps_ResultTupleSlot;
}
break;
case T_SeqScanState:
{
SeqScanState *scanstate = (SeqScanState *) node;
slot = scanstate->ps.ps_ResultTupleSlot;
}
break;
case T_IndexScanState:
{
IndexScanState *scanstate = (IndexScanState *) node;
slot = scanstate->ss.ps.ps_ResultTupleSlot;
}
break;
case T_TidScanState:
{
TidScanState *scanstate = (TidScanState *) node;
slot = scanstate->ss.ps.ps_ResultTupleSlot;
}
break;
case T_SubqueryScanState:
{
SubqueryScanState *scanstate = (SubqueryScanState *) node;
slot = scanstate->ss.ps.ps_ResultTupleSlot;
}
break;
case T_FunctionScanState:
{
FunctionScanState *scanstate = (FunctionScanState *) node;
slot = scanstate->ss.ps.ps_ResultTupleSlot;
}
break;
case T_NestLoopState:
{
NestLoopState *nlstate = (NestLoopState *) node;
slot = nlstate->js.ps.ps_ResultTupleSlot;
}
break;
case T_MergeJoinState:
{
MergeJoinState *mergestate = (MergeJoinState *) node;
slot = mergestate->js.ps.ps_ResultTupleSlot;
}
break;
case T_HashJoinState:
{
HashJoinState *hashjoinstate = (HashJoinState *) node;
slot = hashjoinstate->js.ps.ps_ResultTupleSlot;
}
break;
case T_MaterialState:
{
MaterialState *matstate = (MaterialState *) node;
slot = matstate->ss.ss_ScanTupleSlot;
}
break;
case T_SortState:
{
SortState *sortstate = (SortState *) node;
slot = sortstate->ss.ss_ScanTupleSlot;
}
break;
case T_GroupState:
{
GroupState *grpstate = (GroupState *) node;
slot = grpstate->ss.ps.ps_ResultTupleSlot;
}
break;
case T_AggState:
{
AggState *aggstate = (AggState *) node;
slot = aggstate->ss.ps.ps_ResultTupleSlot;
}
break;
case T_UniqueState:
{
UniqueState *uniquestate = (UniqueState *) node;
slot = uniquestate->ps.ps_ResultTupleSlot;
}
break;
case T_HashState:
{
HashState *hashstate = (HashState *) node;
slot = hashstate->ps.ps_ResultTupleSlot;
}
break;
case T_SetOpState:
{
SetOpState *setopstate = (SetOpState *) node;
slot = setopstate->ps.ps_ResultTupleSlot;
}
break;
case T_LimitState:
{
LimitState *limitstate = (LimitState *) node;
slot = limitstate->ps.ps_ResultTupleSlot;
}
break;
default:
/*
* should never get here
*/
elog(ERROR, "ExecGetTupType: node type %d unsupported",
(int) nodeTag(node));
return NULL;
}
return slot->ttc_tupleDescriptor;
}