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https://github.com/postgres/postgres.git
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3a94e789f5
(Don't forget that an alias is required.) Views reimplemented as expanding to subselect-in-FROM. Grouping, aggregates, DISTINCT in views actually work now (he says optimistically). No UNION support in subselects/views yet, but I have some ideas about that. Rule-related permissions checking moved out of rewriter and into executor. INITDB REQUIRED!
535 lines
12 KiB
C
535 lines
12 KiB
C
/*-------------------------------------------------------------------------
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*
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* execProcnode.c
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* contains dispatch functions which call the appropriate "initialize",
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* "get a tuple", and "cleanup" routines for the given node type.
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* If the node has children, then it will presumably call ExecInitNode,
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* ExecProcNode, or ExecEndNode on its subnodes and do the appropriate
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* processing..
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*
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* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/executor/execProcnode.c,v 1.20 2000/09/29 18:21:29 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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/*
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* INTERFACE ROUTINES
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* ExecInitNode - initialize a plan node and its subplans
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* ExecProcNode - get a tuple by executing the plan node
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* ExecEndNode - shut down a plan node and its subplans
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*
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* NOTES
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* This used to be three files. It is now all combined into
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* one file so that it is easier to keep ExecInitNode, ExecProcNode,
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* and ExecEndNode in sync when new nodes are added.
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*
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* EXAMPLE
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* suppose we want the age of the manager of the shoe department and
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* the number of employees in that department. so we have the query:
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*
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* retrieve (DEPT.no_emps, EMP.age)
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* where EMP.name = DEPT.mgr and
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* DEPT.name = "shoe"
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*
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* Suppose the planner gives us the following plan:
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*
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* Nest Loop (DEPT.mgr = EMP.name)
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* / \
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* / \
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* Seq Scan Seq Scan
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* DEPT EMP
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* (name = "shoe")
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*
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* ExecStart() is called first.
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* It calls InitPlan() which calls ExecInitNode() on
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* the root of the plan -- the nest loop node.
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*
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* * ExecInitNode() notices that it is looking at a nest loop and
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* as the code below demonstrates, it calls ExecInitNestLoop().
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* Eventually this calls ExecInitNode() on the right and left subplans
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* and so forth until the entire plan is initialized.
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*
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* * Then when ExecRun() is called, it calls ExecutePlan() which
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* calls ExecProcNode() repeatedly on the top node of the plan.
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* Each time this happens, ExecProcNode() will end up calling
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* ExecNestLoop(), which calls ExecProcNode() on its subplans.
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* Each of these subplans is a sequential scan so ExecSeqScan() is
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* called. The slots returned by ExecSeqScan() may contain
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* tuples which contain the attributes ExecNestLoop() uses to
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* form the tuples it returns.
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*
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* * Eventually ExecSeqScan() stops returning tuples and the nest
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* loop join ends. Lastly, ExecEnd() calls ExecEndNode() which
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* calls ExecEndNestLoop() which in turn calls ExecEndNode() on
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* its subplans which result in ExecEndSeqScan().
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*
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* This should show how the executor works by having
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* ExecInitNode(), ExecProcNode() and ExecEndNode() dispatch
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* their work to the appopriate node support routines which may
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* in turn call these routines themselves on their subplans.
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*
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*/
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#include "postgres.h"
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#include "executor/executor.h"
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#include "executor/nodeAgg.h"
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#include "executor/nodeAppend.h"
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#include "executor/nodeGroup.h"
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#include "executor/nodeHash.h"
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#include "executor/nodeHashjoin.h"
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#include "executor/nodeIndexscan.h"
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#include "executor/nodeTidscan.h"
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#include "executor/nodeMaterial.h"
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#include "executor/nodeMergejoin.h"
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#include "executor/nodeNestloop.h"
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#include "executor/nodeResult.h"
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#include "executor/nodeSeqscan.h"
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#include "executor/nodeSort.h"
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#include "executor/nodeSubplan.h"
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#include "executor/nodeSubqueryscan.h"
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#include "executor/nodeUnique.h"
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#include "miscadmin.h"
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#include "tcop/tcopprot.h"
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/* ------------------------------------------------------------------------
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* ExecInitNode
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*
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* Recursively initializes all the nodes in the plan rooted
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* at 'node'.
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*
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* Initial States:
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* 'node' is the plan produced by the query planner
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*
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* returns TRUE/FALSE on whether the plan was successfully initialized
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* ------------------------------------------------------------------------
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*/
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bool
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ExecInitNode(Plan *node, EState *estate, Plan *parent)
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{
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bool result;
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List *subp;
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/* ----------------
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* do nothing when we get to the end
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* of a leaf on tree.
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* ----------------
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*/
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if (node == NULL)
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return FALSE;
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foreach(subp, node->initPlan)
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{
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result = ExecInitSubPlan((SubPlan *) lfirst(subp), estate, node);
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if (result == FALSE)
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return FALSE;
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}
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switch (nodeTag(node))
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{
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/* ----------------
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* control nodes
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* ----------------
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*/
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case T_Result:
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result = ExecInitResult((Result *) node, estate, parent);
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break;
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case T_Append:
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result = ExecInitAppend((Append *) node, estate, parent);
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break;
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/* ----------------
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* scan nodes
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* ----------------
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*/
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case T_SeqScan:
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result = ExecInitSeqScan((SeqScan *) node, estate, parent);
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break;
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case T_IndexScan:
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result = ExecInitIndexScan((IndexScan *) node, estate, parent);
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break;
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case T_TidScan:
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result = ExecInitTidScan((TidScan *) node, estate, parent);
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break;
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case T_SubqueryScan:
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result = ExecInitSubqueryScan((SubqueryScan *) node, estate,
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parent);
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break;
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/* ----------------
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* join nodes
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* ----------------
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*/
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case T_NestLoop:
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result = ExecInitNestLoop((NestLoop *) node, estate, parent);
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break;
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case T_MergeJoin:
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result = ExecInitMergeJoin((MergeJoin *) node, estate, parent);
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break;
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case T_Hash:
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result = ExecInitHash((Hash *) node, estate, parent);
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break;
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case T_HashJoin:
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result = ExecInitHashJoin((HashJoin *) node, estate, parent);
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break;
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/* ----------------
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* materialization nodes
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* ----------------
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*/
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case T_Material:
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result = ExecInitMaterial((Material *) node, estate, parent);
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break;
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case T_Sort:
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result = ExecInitSort((Sort *) node, estate, parent);
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break;
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case T_Unique:
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result = ExecInitUnique((Unique *) node, estate, parent);
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break;
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case T_Group:
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result = ExecInitGroup((Group *) node, estate, parent);
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break;
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case T_Agg:
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result = ExecInitAgg((Agg *) node, estate, parent);
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break;
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default:
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elog(ERROR, "ExecInitNode: node %d unsupported", nodeTag(node));
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result = FALSE;
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}
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if (result != FALSE)
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{
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foreach(subp, node->subPlan)
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{
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result = ExecInitSubPlan((SubPlan *) lfirst(subp), estate, node);
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if (result == FALSE)
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return FALSE;
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}
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}
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return result;
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}
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/* ----------------------------------------------------------------
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* ExecProcNode
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*
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* Initial States:
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* the query tree must be initialized once by calling ExecInit.
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* ----------------------------------------------------------------
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*/
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TupleTableSlot *
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ExecProcNode(Plan *node, Plan *parent)
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{
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TupleTableSlot *result;
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/* ----------------
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* deal with NULL nodes..
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* ----------------
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*/
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if (QueryCancel)
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CancelQuery();
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if (node == NULL)
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return NULL;
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if (node->chgParam != NULL) /* something changed */
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ExecReScan(node, NULL, parent); /* let ReScan handle this */
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switch (nodeTag(node))
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{
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/* ----------------
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* control nodes
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* ----------------
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*/
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case T_Result:
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result = ExecResult((Result *) node);
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break;
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case T_Append:
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result = ExecProcAppend((Append *) node);
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break;
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/* ----------------
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* scan nodes
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* ----------------
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*/
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case T_SeqScan:
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result = ExecSeqScan((SeqScan *) node);
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break;
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case T_IndexScan:
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result = ExecIndexScan((IndexScan *) node);
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break;
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case T_TidScan:
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result = ExecTidScan((TidScan *) node);
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break;
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case T_SubqueryScan:
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result = ExecSubqueryScan((SubqueryScan *) node);
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break;
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/* ----------------
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* join nodes
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* ----------------
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*/
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case T_NestLoop:
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result = ExecNestLoop((NestLoop *) node);
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break;
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case T_MergeJoin:
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result = ExecMergeJoin((MergeJoin *) node);
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break;
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case T_Hash:
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result = ExecHash((Hash *) node);
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break;
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case T_HashJoin:
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result = ExecHashJoin((HashJoin *) node);
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break;
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/* ----------------
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* materialization nodes
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* ----------------
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*/
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case T_Material:
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result = ExecMaterial((Material *) node);
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break;
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case T_Sort:
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result = ExecSort((Sort *) node);
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break;
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case T_Unique:
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result = ExecUnique((Unique *) node);
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break;
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case T_Group:
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result = ExecGroup((Group *) node);
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break;
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case T_Agg:
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result = ExecAgg((Agg *) node);
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break;
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default:
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elog(ERROR, "ExecProcNode: node %d unsupported", nodeTag(node));
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result = NULL;
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}
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return result;
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}
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int
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ExecCountSlotsNode(Plan *node)
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{
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if (node == (Plan *) NULL)
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return 0;
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switch (nodeTag(node))
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{
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/* ----------------
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* control nodes
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* ----------------
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*/
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case T_Result:
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return ExecCountSlotsResult((Result *) node);
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case T_Append:
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return ExecCountSlotsAppend((Append *) node);
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/* ----------------
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* scan nodes
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* ----------------
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*/
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case T_SeqScan:
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return ExecCountSlotsSeqScan((SeqScan *) node);
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case T_IndexScan:
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return ExecCountSlotsIndexScan((IndexScan *) node);
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case T_TidScan:
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return ExecCountSlotsTidScan((TidScan *) node);
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case T_SubqueryScan:
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return ExecCountSlotsSubqueryScan((SubqueryScan *) node);
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/* ----------------
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* join nodes
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* ----------------
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*/
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case T_NestLoop:
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return ExecCountSlotsNestLoop((NestLoop *) node);
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case T_MergeJoin:
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return ExecCountSlotsMergeJoin((MergeJoin *) node);
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case T_Hash:
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return ExecCountSlotsHash((Hash *) node);
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case T_HashJoin:
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return ExecCountSlotsHashJoin((HashJoin *) node);
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/* ----------------
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* materialization nodes
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* ----------------
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*/
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case T_Material:
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return ExecCountSlotsMaterial((Material *) node);
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case T_Sort:
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return ExecCountSlotsSort((Sort *) node);
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case T_Unique:
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return ExecCountSlotsUnique((Unique *) node);
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case T_Group:
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return ExecCountSlotsGroup((Group *) node);
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case T_Agg:
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return ExecCountSlotsAgg((Agg *) node);
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default:
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elog(ERROR, "ExecCountSlotsNode: node not yet supported: %d",
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nodeTag(node));
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break;
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}
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return 0;
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}
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/* ----------------------------------------------------------------
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* ExecEndNode
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*
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* Recursively cleans up all the nodes in the plan rooted
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* at 'node'.
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*
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* After this operation, the query plan will not be able to
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* processed any further. This should be called only after
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* the query plan has been fully executed.
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* ----------------------------------------------------------------
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*/
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void
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ExecEndNode(Plan *node, Plan *parent)
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{
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List *subp;
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/* ----------------
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* do nothing when we get to the end
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* of a leaf on tree.
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* ----------------
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*/
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if (node == NULL)
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return;
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foreach(subp, node->initPlan)
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ExecEndSubPlan((SubPlan *) lfirst(subp));
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foreach(subp, node->subPlan)
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ExecEndSubPlan((SubPlan *) lfirst(subp));
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if (node->chgParam != NULL)
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{
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freeList(node->chgParam);
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node->chgParam = NULL;
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}
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switch (nodeTag(node))
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{
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/* ----------------
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* control nodes
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* ----------------
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*/
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case T_Result:
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ExecEndResult((Result *) node);
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break;
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case T_Append:
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ExecEndAppend((Append *) node);
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break;
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/* ----------------
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* scan nodes
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* ----------------
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*/
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case T_SeqScan:
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ExecEndSeqScan((SeqScan *) node);
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break;
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case T_IndexScan:
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ExecEndIndexScan((IndexScan *) node);
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break;
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case T_TidScan:
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ExecEndTidScan((TidScan *) node);
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break;
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case T_SubqueryScan:
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ExecEndSubqueryScan((SubqueryScan *) node);
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break;
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/* ----------------
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* join nodes
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* ----------------
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*/
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case T_NestLoop:
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ExecEndNestLoop((NestLoop *) node);
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break;
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case T_MergeJoin:
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ExecEndMergeJoin((MergeJoin *) node);
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break;
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case T_Hash:
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ExecEndHash((Hash *) node);
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break;
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case T_HashJoin:
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ExecEndHashJoin((HashJoin *) node);
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break;
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/* ----------------
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* materialization nodes
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* ----------------
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*/
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case T_Material:
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ExecEndMaterial((Material *) node);
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break;
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case T_Sort:
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ExecEndSort((Sort *) node);
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break;
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case T_Unique:
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ExecEndUnique((Unique *) node);
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break;
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case T_Group:
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ExecEndGroup((Group *) node);
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break;
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case T_Agg:
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ExecEndAgg((Agg *) node);
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break;
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default:
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elog(ERROR, "ExecEndNode: node %d unsupported", nodeTag(node));
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break;
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}
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}
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