src/include/executor/execdesc.h

   1 /*-------------------------------------------------------------------------
   2  *
   3  * execdesc.h
   4  *        plan and query descriptor accessor macros used by the executor
   5  *        and related modules.
   6  *
   7  *
   8  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
   9  * Portions Copyright (c) 1994, Regents of the University of California
  10  *
  11  * $PostgreSQL$
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #ifndef EXECDESC_H
  16 #define EXECDESC_H
  17
  18 #include "nodes/execnodes.h"
  19 #include "nodes/plannodes.h"
  20 #include "tcop/dest.h"
  21
  22
  23 /* ----------------
  24  *              query descriptor:
  25  *
  26  *      a QueryDesc encapsulates everything that the executor
  27  *      needs to execute the query.
  28  *
  29  *      For the convenience of SQL-language functions, we also support QueryDescs
  30  *      containing utility statements; these must not be passed to the executor
  31  *      however.
  32  * ---------------------
  33  */
  34 typedef struct QueryDesc
  35 {
  36         /* These fields are provided by CreateQueryDesc */
  37         CmdType         operation;              /* CMD_SELECT, CMD_UPDATE, etc. */
  38         PlannedStmt *plannedstmt;       /* planner's output, or null if utility */
  39         Node       *utilitystmt;        /* utility statement, or null */
  40         Snapshot        snapshot;               /* snapshot to use for query */
  41         Snapshot        crosscheck_snapshot;    /* crosscheck for RI update/delete */
  42         DestReceiver *dest;                     /* the destination for tuple output */
  43         ParamListInfo params;           /* param values being passed in */
  44         bool            doInstrument;   /* TRUE requests runtime instrumentation */
  45
  46         /* These fields are set by ExecutorStart */
  47         TupleDesc       tupDesc;                /* descriptor for result tuples */
  48         EState     *estate;                     /* executor's query-wide state */
  49         PlanState  *planstate;          /* tree of per-plan-node state */
  50 } QueryDesc;
  51
  52 /* in pquery.c */
  53 extern QueryDesc *CreateQueryDesc(PlannedStmt *plannedstmt,
  54                                 Snapshot snapshot,
  55                                 Snapshot crosscheck_snapshot,
  56                                 DestReceiver *dest,
  57                                 ParamListInfo params,
  58                                 bool doInstrument);
  59
  60 extern QueryDesc *CreateUtilityQueryDesc(Node *utilitystmt,
  61                                            Snapshot snapshot,
  62                                            DestReceiver *dest,
  63                                            ParamListInfo params);
  64
  65 extern void FreeQueryDesc(QueryDesc *qdesc);
  66
  67 #endif   /* EXECDESC_H  */