execdesc.h

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

/*-------------------------------------------------------------------------
 *
 * execdesc.h
 *	  plan and query descriptor accessor macros used by the executor
 *	  and related modules.
 *
 *
 * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * $PostgreSQL: pgsql/src/include/executor/execdesc.h,v 1.30 2004/12/31 22:03:29 pgsql Exp $
 *
 *-------------------------------------------------------------------------
 */
#ifndef EXECDESC_H
#define EXECDESC_H

#include "nodes/parsenodes.h"
#include "nodes/execnodes.h"
#include "tcop/dest.h"


/* ----------------
 *		query descriptor:
 *
 *	a QueryDesc encapsulates everything that the executor
 *	needs to execute the query
 * ---------------------
 */
typedef struct QueryDesc
{
	/* These fields are provided by CreateQueryDesc */
	CmdType		operation;		/* CMD_SELECT, CMD_UPDATE, etc. */
	Query	   *parsetree;		/* rewritten parsetree */
	Plan	   *plantree;		/* planner's output */
	Snapshot	snapshot;		/* snapshot to use for query */
	Snapshot	crosscheck_snapshot;	/* crosscheck for RI update/delete */
	DestReceiver *dest;			/* the destination for tuple output */
	ParamListInfo params;		/* param values being passed in */
	bool		doInstrument;	/* TRUE requests runtime instrumentation */

	/* These fields are set by ExecutorStart */
	TupleDesc	tupDesc;		/* descriptor for result tuples */
	EState	   *estate;			/* executor's query-wide state */
	PlanState  *planstate;		/* tree of per-plan-node state */
} QueryDesc;

/* in pquery.c */
extern QueryDesc *CreateQueryDesc(Query *parsetree, Plan *plantree,
				Snapshot snapshot,
				Snapshot crosscheck_snapshot,
				DestReceiver *dest,
				ParamListInfo params,
				bool doInstrument);

extern void FreeQueryDesc(QueryDesc *qdesc);

#endif   /* EXECDESC_H  */