/*------------------------------------------------------------------------- * * 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 1.20 2000/09/29 18:21:29 tgl 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/nodeSubqueryscan.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; case T_TidScan: result = ExecInitTidScan((TidScan *) node, estate, parent); break; case T_SubqueryScan: result = ExecInitSubqueryScan((SubqueryScan *) 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; case T_Hash: result = ExecInitHash((Hash *) node, estate, parent); break; case T_HashJoin: result = ExecInitHashJoin((HashJoin *) 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; 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; case T_TidScan: result = ExecTidScan((TidScan *) node); break; case T_SubqueryScan: result = ExecSubqueryScan((SubqueryScan *) node); break; /* ---------------- * join nodes * ---------------- */ case T_NestLoop: result = ExecNestLoop((NestLoop *) node); break; case T_MergeJoin: result = ExecMergeJoin((MergeJoin *) node); break; case T_Hash: result = ExecHash((Hash *) node); break; case T_HashJoin: result = ExecHashJoin((HashJoin *) 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; 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); case T_TidScan: return ExecCountSlotsTidScan((TidScan *) node); case T_SubqueryScan: return ExecCountSlotsSubqueryScan((SubqueryScan *) node); /* ---------------- * join nodes * ---------------- */ case T_NestLoop: return ExecCountSlotsNestLoop((NestLoop *) node); case T_MergeJoin: return ExecCountSlotsMergeJoin((MergeJoin *) node); case T_Hash: return ExecCountSlotsHash((Hash *) 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_Unique: return ExecCountSlotsUnique((Unique *) node); case T_Group: return ExecCountSlotsGroup((Group *) node); case T_Agg: return ExecCountSlotsAgg((Agg *) 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; case T_TidScan: ExecEndTidScan((TidScan *) node); break; case T_SubqueryScan: ExecEndSubqueryScan((SubqueryScan *) node); break; /* ---------------- * join nodes * ---------------- */ case T_NestLoop: ExecEndNestLoop((NestLoop *) node); break; case T_MergeJoin: ExecEndMergeJoin((MergeJoin *) node); break; case T_Hash: ExecEndHash((Hash *) node); break; case T_HashJoin: ExecEndHashJoin((HashJoin *) 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; default: elog(ERROR, "ExecEndNode: node %d unsupported", nodeTag(node)); break; } }