xasl_cache.h

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/*
 * Copyright 2008 Search Solution Corporation
 * Copyright 2016 CUBRID Corporation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */

/*
 * XASL cache.
 */

#ifndef _XASL_CACHE_H_
#define _XASL_CACHE_H_

#ident "$Id$"

#if !defined (SERVER_MODE) && !defined (SA_MODE)
#error Belongs to server module
#endif /* !defined (SERVER_MODE) && !defined (SA_MODE) */

#include "xasl.h"

// forward definitions
struct compile_context;
struct xasl_unpack_info;

/* Objects related to XASL cache entries. The information includes the object OID, the lock required to use the XASL
 * cache entry and the heap file cardinality.
 * Objects can be classes or serials. The heap file cardinality is only relevant for classes.
 */
typedef struct xcache_related_object XCACHE_RELATED_OBJECT;
struct xcache_related_object
{
  OID oid;
  LOCK lock;
  int tcard;
};

enum xcache_cleanup_reason
{
  XCACHE_CLEANUP_NONE,      /* no cleanup is required */
  XCACHE_CLEANUP_FULL,
  XCACHE_CLEANUP_TIMEOUT
};
typedef enum xcache_cleanup_reason XCACHE_CLEANUP_REASON;

/* XASL cache clones - XASL nodes cached for fast usage.
 *
 */
typedef struct xasl_clone XASL_CLONE;
struct xasl_clone
{
  xasl_unpack_info *xasl_buf;
  XASL_NODE *xasl;
};
#define XASL_CLONE_INITIALIZER { NULL, NULL }
#define XASL_CLONE_AS_ARGS(clone) (clone)->xasl, (clone)->xasl_buf

/*
 * EXECUTION_INFO: query strings: user text, hash string and dumped plan.
 */
typedef struct execution_info EXECUTION_INFO;
struct execution_info
{
  char *sql_hash_text;      /* rewritten query string which is used as hash key */
  char *sql_user_text;      /* original query statement that user input */
  char *sql_plan_text;      /* plans for this query */
};
#define EXEINFO_HASH_TEXT_STRING(einfo) ((einfo)->sql_hash_text ? (einfo)->sql_hash_text : "UNKNOWN HASH TEXT")
#define EXEINFO_USER_TEXT_STRING(einfo) ((einfo)->sql_user_text ? (einfo)->sql_user_text : "UNKNOWN USER TEXT")
#define EXEINFO_PLAN_TEXT_STRING(einfo) ((einfo)->sql_plan_text ? (einfo)->sql_plan_text : "UNKNOWN PLAN TEXT")

#define EXEINFO_AS_ARGS(einfo)  \
  EXEINFO_USER_TEXT_STRING(einfo), EXEINFO_PLAN_TEXT_STRING(einfo), EXEINFO_HASH_TEXT_STRING(einfo)

/* This really belongs more to the query manager rather than query executor. */
/* XASL cache entry type definition */
typedef struct xasl_cache_ent XASL_CACHE_ENTRY;
struct xasl_cache_ent
{
  XASL_ID xasl_id;      /* XASL file identifier */
  /* Not really a file identifier anymore. Maybe we should rename this to XASL_KEY? */
  XASL_STREAM stream;       /* XASL packed stream. */

  /* Latch-free stuff. */
  XASL_CACHE_ENTRY *stack;  /* used in freelist */
  XASL_CACHE_ENTRY *next;   /* used in hash table */
  /* Mutex may be addex here (hopefully it is not necessary). */
  UINT64 del_id;        /* delete transaction ID (for lock free) */


  EXECUTION_INFO sql_info;  /* cache entry hash key, user input string & plan */
  int xasl_header_flag;     /* XASL header info */
  XCACHE_RELATED_OBJECT *related_objects;   /* List of objects referenced by XASL cache entry.
                         * Objects can be:
                         * 1. classes
                         * 2. serials
                         */
  int n_related_objects;    /* size of the related_objects */
  struct timeval time_last_used;    /* when this entry used lastly */
  INT64 ref_count;      /* how many times this entry used */
  INT64 clr_count;      /* how many times related qfile caches are clear */
  int list_ht_no;       /* memory hash table for query result(list file) cache generated by this XASL
                 * referencing by DB_VALUE parameters bound to the result */
  bool free_data_on_uninit; /* set to free entry data on uninit. */

  /* Cache clones */
  XASL_CLONE *cache_clones;
  XASL_CLONE one_clone;
  int n_cache_clones;
  int cache_clones_capacity;
  pthread_mutex_t cache_clones_mutex;

  /* RT check */
  INT64 time_last_rt_check;

  bool initialized;

  // *INDENT-OFF*
  xasl_cache_ent ();
  ~xasl_cache_ent ();

  void init_clone_cache ();
  // *INDENT-ON*
};

enum xasl_cache_search_mode
{
  XASL_CACHE_SEARCH_FOR_EXECUTE = 0,
  XASL_CACHE_SEARCH_FOR_PREPARE = 1,

  XASL_CACHE_SEARCH_GENERIC = XASL_CACHE_SEARCH_FOR_EXECUTE
};
typedef enum xasl_cache_search_mode XASL_CACHE_SEARCH_MODE;

enum xasl_cache_rt_check_result
{
  XASL_CACHE_RECOMPILE_NOT_NEEDED = 0,
  XASL_CACHE_RECOMPILE_EXECUTE = 1,
  XASL_CACHE_RECOMPILE_PREPARE = 2
};

extern int xcache_initialize (THREAD_ENTRY * thread_p);
extern void xcache_finalize (THREAD_ENTRY * thread_p);

extern int xcache_find_sha1 (THREAD_ENTRY * thread_p, const SHA1Hash * sha1, const XASL_CACHE_SEARCH_MODE search_mode,
                 XASL_CACHE_ENTRY ** xcache_entry, xasl_cache_rt_check_result * rt_check);
extern int xcache_find_xasl_id_for_execute (THREAD_ENTRY * thread_p, const XASL_ID * xid,
                        XASL_CACHE_ENTRY ** xcache_entry, XASL_CLONE * xclone);
extern void xcache_unfix (THREAD_ENTRY * thread_p, XASL_CACHE_ENTRY * xcache_entry);
extern int xcache_insert (THREAD_ENTRY * thread_p, const compile_context * context, XASL_STREAM * stream,
              int n_oid, const OID * class_oids, const int *class_locks,
              const int *tcards, XASL_CACHE_ENTRY ** xcache_entry);
extern void xcache_remove_by_oid (THREAD_ENTRY * thread_p, const OID * oid);
extern void xcache_drop_all (THREAD_ENTRY * thread_p);
extern void xcache_dump (THREAD_ENTRY * thread_p, FILE * fp);

extern bool xcache_can_entry_cache_list (XASL_CACHE_ENTRY * xcache_entry);

extern void xcache_retire_clone (THREAD_ENTRY * thread_p, XASL_CACHE_ENTRY * xcache_entry, XASL_CLONE * xclone);
extern int xcache_get_entry_count (void);
extern bool xcache_uses_clones (void);

extern int xcache_invalidate_qcaches (THREAD_ENTRY * thread_p, const OID * oid);

#endif /* _XASL_CACHE_H_ */