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postgresql/src/backend/executor/execProcnode.c
Tom Lane 44d5be0e53 Implement SQL-standard WITH clauses, including WITH RECURSIVE. 
There are some unimplemented aspects: recursive queries must use UNION ALL
(should allow UNION too), and we don't have SEARCH or CYCLE clauses.
These might or might not get done for 8.4, but even without them it's a
pretty useful feature.

There are also a couple of small loose ends and definitional quibbles,
which I'll send a memo about to pgsql-hackers shortly.  But let's land
the patch now so we can get on with other development.

Yoshiyuki Asaba, with lots of help from Tatsuo Ishii and Tom Lane
2008-10-04 21:56:55 +00:00

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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) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/execProcnode.c,v 1.63 2008/10/04 21:56:53 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
*
* 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:
*
* select 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")
*
* ExecutorStart() 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/nodeBitmapAnd.h"
#include "executor/nodeBitmapHeapscan.h"
#include "executor/nodeBitmapIndexscan.h"
#include "executor/nodeBitmapOr.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/nodeRecursiveunion.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 "executor/nodeValuesscan.h"
#include "executor/nodeCtescan.h"
#include "executor/nodeWorktablescan.h"
#include "miscadmin.h"
/* ------------------------------------------------------------------------
* ExecInitNode
*
* Recursively initializes all the nodes in the plan tree rooted
* at 'node'.
*
* Inputs:
* 'node' is the current node of the plan produced by the query planner
* 'estate' is the shared execution state for the plan tree
* 'eflags' is a bitwise OR of flag bits described in executor.h
*
* Returns a PlanState node corresponding to the given Plan node.
* ------------------------------------------------------------------------
*/
PlanState *
ExecInitNode(Plan *node, EState *estate, int eflags)
{
PlanState *result;
List *subps;
ListCell *l;
/*
* 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, eflags);
break;
case T_Append:
result = (PlanState *) ExecInitAppend((Append *) node,
estate, eflags);
break;
case T_RecursiveUnion:
result = (PlanState *) ExecInitRecursiveUnion((RecursiveUnion *) node,
estate, eflags);
break;
case T_BitmapAnd:
result = (PlanState *) ExecInitBitmapAnd((BitmapAnd *) node,
estate, eflags);
break;
case T_BitmapOr:
result = (PlanState *) ExecInitBitmapOr((BitmapOr *) node,
estate, eflags);
break;
/*
* scan nodes
*/
case T_SeqScan:
result = (PlanState *) ExecInitSeqScan((SeqScan *) node,
estate, eflags);
break;
case T_IndexScan:
result = (PlanState *) ExecInitIndexScan((IndexScan *) node,
estate, eflags);
break;
case T_BitmapIndexScan:
result = (PlanState *) ExecInitBitmapIndexScan((BitmapIndexScan *) node,
estate, eflags);
break;
case T_BitmapHeapScan:
result = (PlanState *) ExecInitBitmapHeapScan((BitmapHeapScan *) node,
estate, eflags);
break;
case T_TidScan:
result = (PlanState *) ExecInitTidScan((TidScan *) node,
estate, eflags);
break;
case T_SubqueryScan:
result = (PlanState *) ExecInitSubqueryScan((SubqueryScan *) node,
estate, eflags);
break;
case T_FunctionScan:
result = (PlanState *) ExecInitFunctionScan((FunctionScan *) node,
estate, eflags);
break;
case T_ValuesScan:
result = (PlanState *) ExecInitValuesScan((ValuesScan *) node,
estate, eflags);
break;
case T_CteScan:
result = (PlanState *) ExecInitCteScan((CteScan *) node,
estate, eflags);
break;
case T_WorkTableScan:
result = (PlanState *) ExecInitWorkTableScan((WorkTableScan *) node,
estate, eflags);
break;
/*
* join nodes
*/
case T_NestLoop:
result = (PlanState *) ExecInitNestLoop((NestLoop *) node,
estate, eflags);
break;
case T_MergeJoin:
result = (PlanState *) ExecInitMergeJoin((MergeJoin *) node,
estate, eflags);
break;
case T_HashJoin:
result = (PlanState *) ExecInitHashJoin((HashJoin *) node,
estate, eflags);
break;
/*
* materialization nodes
*/
case T_Material:
result = (PlanState *) ExecInitMaterial((Material *) node,
estate, eflags);
break;
case T_Sort:
result = (PlanState *) ExecInitSort((Sort *) node,
estate, eflags);
break;
case T_Group:
result = (PlanState *) ExecInitGroup((Group *) node,
estate, eflags);
break;
case T_Agg:
result = (PlanState *) ExecInitAgg((Agg *) node,
estate, eflags);
break;
case T_Unique:
result = (PlanState *) ExecInitUnique((Unique *) node,
estate, eflags);
break;
case T_Hash:
result = (PlanState *) ExecInitHash((Hash *) node,
estate, eflags);
break;
case T_SetOp:
result = (PlanState *) ExecInitSetOp((SetOp *) node,
estate, eflags);
break;
case T_Limit:
result = (PlanState *) ExecInitLimit((Limit *) node,
estate, eflags);
break;
default:
elog(ERROR, "unrecognized node type: %d", (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(l, node->initPlan)
{
SubPlan *subplan = (SubPlan *) lfirst(l);
SubPlanState *sstate;
Assert(IsA(subplan, SubPlan));
sstate = ExecInitSubPlan(subplan, result);
subps = lappend(subps, sstate);
}
result->initPlan = subps;
/* Set up instrumentation for this node if requested */
if (estate->es_instrument)
result->instrument = InstrAlloc(1);
return result;
}
/* ----------------------------------------------------------------
* ExecProcNode
*
* Execute the given node to return a(nother) tuple.
* ----------------------------------------------------------------
*/
TupleTableSlot *
ExecProcNode(PlanState *node)
{
TupleTableSlot *result;
CHECK_FOR_INTERRUPTS();
if (node->chgParam != NULL) /* 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 = ExecAppend((AppendState *) node);
break;
case T_RecursiveUnionState:
result = ExecRecursiveUnion((RecursiveUnionState *) node);
break;
/* BitmapAndState does not yield tuples */
/* BitmapOrState does not yield tuples */
/*
* scan nodes
*/
case T_SeqScanState:
result = ExecSeqScan((SeqScanState *) node);
break;
case T_IndexScanState:
result = ExecIndexScan((IndexScanState *) node);
break;
/* BitmapIndexScanState does not yield tuples */
case T_BitmapHeapScanState:
result = ExecBitmapHeapScan((BitmapHeapScanState *) 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;
case T_ValuesScanState:
result = ExecValuesScan((ValuesScanState *) node);
break;
case T_CteScanState:
result = ExecCteScan((CteScanState *) node);
break;
case T_WorkTableScanState:
result = ExecWorkTableScan((WorkTableScanState *) 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, "unrecognized node type: %d", (int) nodeTag(node));
result = NULL;
break;
}
if (node->instrument)
InstrStopNode(node->instrument, TupIsNull(result) ? 0.0 : 1.0);
return result;
}
/* ----------------------------------------------------------------
* MultiExecProcNode
*
* Execute a node that doesn't return individual tuples
* (it might return a hashtable, bitmap, etc). Caller should
* check it got back the expected kind of Node.
*
* This has essentially the same responsibilities as ExecProcNode,
* but it does not do InstrStartNode/InstrStopNode (mainly because
* it can't tell how many returned tuples to count). Each per-node
* function must provide its own instrumentation support.
* ----------------------------------------------------------------
*/
Node *
MultiExecProcNode(PlanState *node)
{
Node *result;
CHECK_FOR_INTERRUPTS();
if (node->chgParam != NULL) /* something changed */
ExecReScan(node, NULL); /* let ReScan handle this */
switch (nodeTag(node))
{
/*
* Only node types that actually support multiexec will be listed
*/
case T_HashState:
result = MultiExecHash((HashState *) node);
break;
case T_BitmapIndexScanState:
result = MultiExecBitmapIndexScan((BitmapIndexScanState *) node);
break;
case T_BitmapAndState:
result = MultiExecBitmapAnd((BitmapAndState *) node);
break;
case T_BitmapOrState:
result = MultiExecBitmapOr((BitmapOrState *) node);
break;
default:
elog(ERROR, "unrecognized node type: %d", (int) nodeTag(node));
result = NULL;
break;
}
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);
case T_RecursiveUnion:
return ExecCountSlotsRecursiveUnion((RecursiveUnion *) node);
case T_BitmapAnd:
return ExecCountSlotsBitmapAnd((BitmapAnd *) node);
case T_BitmapOr:
return ExecCountSlotsBitmapOr((BitmapOr *) node);
/*
* scan nodes
*/
case T_SeqScan:
return ExecCountSlotsSeqScan((SeqScan *) node);
case T_IndexScan:
return ExecCountSlotsIndexScan((IndexScan *) node);
case T_BitmapIndexScan:
return ExecCountSlotsBitmapIndexScan((BitmapIndexScan *) node);
case T_BitmapHeapScan:
return ExecCountSlotsBitmapHeapScan((BitmapHeapScan *) node);
case T_TidScan:
return ExecCountSlotsTidScan((TidScan *) node);
case T_SubqueryScan:
return ExecCountSlotsSubqueryScan((SubqueryScan *) node);
case T_FunctionScan:
return ExecCountSlotsFunctionScan((FunctionScan *) node);
case T_ValuesScan:
return ExecCountSlotsValuesScan((ValuesScan *) node);
case T_CteScan:
return ExecCountSlotsCteScan((CteScan *) node);
case T_WorkTableScan:
return ExecCountSlotsWorkTableScan((WorkTableScan *) 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, "unrecognized node type: %d", (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)
{
/*
* do nothing when we get to the end of a leaf on tree.
*/
if (node == NULL)
return;
if (node->chgParam != NULL)
{
bms_free(node->chgParam);
node->chgParam = NULL;
}
switch (nodeTag(node))
{
/*
* control nodes
*/
case T_ResultState:
ExecEndResult((ResultState *) node);
break;
case T_AppendState:
ExecEndAppend((AppendState *) node);
break;
case T_RecursiveUnionState:
ExecEndRecursiveUnion((RecursiveUnionState *) node);
break;
case T_BitmapAndState:
ExecEndBitmapAnd((BitmapAndState *) node);
break;
case T_BitmapOrState:
ExecEndBitmapOr((BitmapOrState *) node);
break;
/*
* scan nodes
*/
case T_SeqScanState:
ExecEndSeqScan((SeqScanState *) node);
break;
case T_IndexScanState:
ExecEndIndexScan((IndexScanState *) node);
break;
case T_BitmapIndexScanState:
ExecEndBitmapIndexScan((BitmapIndexScanState *) node);
break;
case T_BitmapHeapScanState:
ExecEndBitmapHeapScan((BitmapHeapScanState *) node);
break;
case T_TidScanState:
ExecEndTidScan((TidScanState *) node);
break;
case T_SubqueryScanState:
ExecEndSubqueryScan((SubqueryScanState *) node);
break;
case T_FunctionScanState:
ExecEndFunctionScan((FunctionScanState *) node);
break;
case T_ValuesScanState:
ExecEndValuesScan((ValuesScanState *) node);
break;
case T_CteScanState:
ExecEndCteScan((CteScanState *) node);
break;
case T_WorkTableScanState:
ExecEndWorkTableScan((WorkTableScanState *) 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, "unrecognized node type: %d", (int) nodeTag(node));
break;
}
}
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