File subquery_cache.h¶

File List > cubrid > src > query > subquery_cache.h
/*
 * 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.
 *
 */

/*
 * subquery_cache.h - Correlated Scalar Subquery Result Cache.
 */

#ifndef _SUBQUERY_CACHE_H_
#define _SUBQUERY_CACHE_H_

#ident "$Id$"

typedef union sq_regu_value SQ_REGU_VALUE;
typedef struct sq_key SQ_KEY;
typedef struct sq_val SQ_VAL;
typedef struct sq_cache SQ_CACHE;

extern int sq_cache_initialize (xasl_node * xasl);
extern int sq_put (THREAD_ENTRY * thread_p, SQ_KEY * key, xasl_node * xasl, REGU_VARIABLE * result);
extern bool sq_get (THREAD_ENTRY * thread_p, SQ_KEY * key, xasl_node * xasl, REGU_VARIABLE * regu_var);
extern void sq_cache_destroy (THREAD_ENTRY * thread_p, SQ_CACHE * sq_cache);
extern SQ_KEY *sq_make_key (THREAD_ENTRY * thread_p, xasl_node * xasl);
extern void sq_free_key (THREAD_ENTRY * thread_p, SQ_KEY * key);

#define SQ_CACHE_MIN_HIT_RATIO 9    /* it means 90% */
#define SQ_CACHE_EXPECTED_ENTRY_SIZE 512

#define SQ_CACHE_HT(xasl)       (xasl)->sq_cache->ht
#define SQ_CACHE_ENABLED(xasl)      (xasl)->sq_cache->enabled
#define SQ_CACHE_KEY_STRUCT(xasl)   (xasl)->sq_cache->sq_key_struct
#define SQ_CACHE_HIT(xasl)              (xasl)->sq_cache->stats.hit
#define SQ_CACHE_MISS(xasl)             (xasl)->sq_cache->stats.miss
#define SQ_CACHE_SIZE(xasl)             (xasl)->sq_cache->size
#define SQ_CACHE_SIZE_MAX(xasl)         (xasl)->sq_cache->size_max

struct sq_cache
{
  SQ_KEY *sq_key_struct;
#if defined (SERVER_MODE) || defined (SA_MODE)
  MHT_TABLE *ht;
  UINT64 size_max;
  UINT64 size;
  bool enabled;
  struct
  {
    int hit;
    int miss;
  } stats;
#endif              /* defined (SERVER_MODE) || defined (SA_MODE) */
};

enum sq_type
{
  SQ_TYPE_XASL = 0,
  SQ_TYPE_PRED,
  SQ_TYPE_REGU_VAR,
  SQ_TYPE_DBVAL
};

typedef enum sq_type SQ_TYPE;

union sq_regu_value
{
  /* fields used by both XASL interpreter and regulator */
  DB_VALUE *dbvalptr;       /* for constant values */
  bool exists;
};

struct sq_key
{
  DB_VALUE **dbv_array;
  int n_elements;
};

struct sq_val
{
  SQ_REGU_VALUE val;
  REGU_DATATYPE type;
};

#endif /* _SUBQUERY_CACHE_H_ */