pool_relcache.h

/* -*-pgsql-c-*- */
/*
 *
 * $Header: /cvsroot/pgpool/pgpool-II/pool_relcache.h,v 1.4 2011/01/16 10:31:38 t-ishii Exp $
 *
 * pgpool: a language independent connection pool server for PostgreSQL 
 * written by Tatsuo Ishii
 *
 * Copyright (c) 2003-2010	PgPool Global Development Group
 *
 * Permission to use, copy, modify, and distribute this software and
 * its documentation for any purpose and without fee is hereby
 * granted, provided that the above copyright notice appear in all
 * copies and that both that copyright notice and this permission
 * notice appear in supporting documentation, and that the name of the
 * author not be used in advertising or publicity pertaining to
 * distribution of the software without specific, written prior
 * permission. The author makes no representations about the
 * suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * pool_relcache.h.: pool_relcache.c related header file
 *
 */

#ifndef POOL_RELCACHE_H
#define POOL_RELCACHE_H

/* ------------------------
 * Relation cache structure
 *-------------------------
*/
#define MAX_ITEM_LENGTH	1024

/* Relation lookup cache structure */

typedef void *(*func_ptr) ();

typedef struct {
	char dbname[MAX_ITEM_LENGTH];	/* database name */
	char relname[MAX_ITEM_LENGTH];	/* table name */
	void *data;	/* user data */
	int refcnt;		/* reference count */
	int session_id;		/* LocalSessionId */
	time_t expire;		/* cache expiration absolute time in seconds */
} PoolRelCache;

typedef struct {
	int num;		/* number of cache items */
	char sql[MAX_ITEM_LENGTH];	/* Query to relation */
	/*
	 * User defined function to be called at data register.
	 * Argument is POOL_SELECT_RESULT *.
	 * This function must return a pointer to be
	 * saved in cache->data.
	 */
	func_ptr	register_func;
	/*
	 * User defined function to be called at data unregister.
	 * Argument cache->data.
	 */
	func_ptr	unregister_func;
	bool cache_is_session_local;		/* True if cache life time is session local */
	PoolRelCache *cache;	/* cache data */
} POOL_RELCACHE;

extern POOL_RELCACHE *pool_create_relcache(int cachesize, char *sql,
									func_ptr register_func, func_ptr unregister_func,
									bool issessionlocal);
extern void pool_discard_relcache(POOL_RELCACHE *relcache);
extern void *pool_search_relcache(POOL_RELCACHE *relcache, POOL_CONNECTION_POOL *backend, char *table);
extern void *int_register_func(POOL_SELECT_RESULT *res);
extern void *int_unregister_func(void *data);
extern void *string_register_func(POOL_SELECT_RESULT *res);
extern void *string_unregister_func(void *data);

#endif /* POOL_RELCACHE_H */