polardbxengine/storage/innobase/ha/hash0hash.cc

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/** @file ha/hash0hash.cc
 The simple hash table utility

 Created 5/20/1997 Heikki Tuuri
 *******************************************************/

#include "hash0hash.h"
#include "mem0mem.h"
#include "sync0sync.h"

#ifndef UNIV_HOTBACKUP

/** Reserves all the locks of a hash table, in an ascending order. */
void hash_lock_x_all(hash_table_t *table) /*!< in: hash table */
{
  ut_ad(table->type == HASH_TABLE_SYNC_RW_LOCK);

  for (ulint i = 0; i < table->n_sync_obj; i++) {
    rw_lock_t *lock = table->sync_obj.rw_locks + i;

    ut_ad(!rw_lock_own(lock, RW_LOCK_S));
    ut_ad(!rw_lock_own(lock, RW_LOCK_X));

    rw_lock_x_lock(lock);
  }
}

/** Releases all the locks of a hash table, in an ascending order. */
void hash_unlock_x_all(hash_table_t *table) /*!< in: hash table */
{
  ut_ad(table->type == HASH_TABLE_SYNC_RW_LOCK);

  for (ulint i = 0; i < table->n_sync_obj; i++) {
    rw_lock_t *lock = table->sync_obj.rw_locks + i;

    ut_ad(rw_lock_own(lock, RW_LOCK_X));

    rw_lock_x_unlock(lock);
  }
}

/** Releases all but passed in lock of a hash table, */
void hash_unlock_x_all_but(hash_table_t *table,  /*!< in: hash table */
                           rw_lock_t *keep_lock) /*!< in: lock to keep */
{
  ut_ad(table->type == HASH_TABLE_SYNC_RW_LOCK);

  for (ulint i = 0; i < table->n_sync_obj; i++) {
    rw_lock_t *lock = table->sync_obj.rw_locks + i;

    ut_ad(rw_lock_own(lock, RW_LOCK_X));

    if (keep_lock != lock) {
      rw_lock_x_unlock(lock);
    }
  }
}

#endif /* !UNIV_HOTBACKUP */

/** Creates a hash table with >= n array cells. The actual number of cells is
 chosen to be a prime number slightly bigger than n.
 @return own: created table */
hash_table_t *hash_create(ulint n) /*!< in: number of array cells */
{
  hash_cell_t *array;
  ulint prime;
  hash_table_t *table;

  prime = ut_find_prime(n);

  table = static_cast<hash_table_t *>(ut_malloc_nokey(sizeof(hash_table_t)));

  array =
      static_cast<hash_cell_t *>(ut_malloc_nokey(sizeof(hash_cell_t) * prime));

  /* The default type of hash_table is HASH_TABLE_SYNC_NONE i.e.:
  the caller is responsible for access control to the table. */
  table->type = HASH_TABLE_SYNC_NONE;
  table->cells = array;
  table->n_cells = prime;
#ifndef UNIV_HOTBACKUP
#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
  table->adaptive = FALSE;
#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
  table->n_sync_obj = 0;
  table->sync_obj.mutexes = NULL;
  table->heaps = NULL;
#endif /* !UNIV_HOTBACKUP */
  table->heap = NULL;
  ut_d(table->magic_n = HASH_TABLE_MAGIC_N);

  /* Initialize the cell array */
  hash_table_clear(table);

  return (table);
}

/** Frees a hash table. */
void hash_table_free(hash_table_t *table) /*!< in, own: hash table */
{
  ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);

  ut_free(table->cells);
  ut_free(table);
}

#ifndef UNIV_HOTBACKUP
/** Creates a sync object array to protect a hash table. "::sync_obj" can be
mutexes or rw_locks depening on the type of hash table.
@param[in]	table		hash table
@param[in]	type		HASH_TABLE_SYNC_MUTEX or
                                HASH_TABLE_SYNC_RW_LOCK
@param[in]	id		latch ID
@param[in]	n_sync_obj	number of sync objects, must be a power of 2 */
void hash_create_sync_obj(hash_table_t *table, enum hash_table_sync_t type,
                          latch_id_t id, ulint n_sync_obj) {
  ut_a(n_sync_obj > 0);
  ut_a(ut_is_2pow(n_sync_obj));
  ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);

  table->type = type;

  switch (table->type) {
    case HASH_TABLE_SYNC_MUTEX:
      table->sync_obj.mutexes = static_cast<ib_mutex_t *>(
          ut_malloc_nokey(n_sync_obj * sizeof(ib_mutex_t)));

      for (ulint i = 0; i < n_sync_obj; i++) {
        mutex_create(id, table->sync_obj.mutexes + i);
      }

      break;

    case HASH_TABLE_SYNC_RW_LOCK: {
      latch_level_t level = sync_latch_get_level(id);

      ut_a(level != SYNC_UNKNOWN);

      table->sync_obj.rw_locks = static_cast<rw_lock_t *>(
          ut_malloc_nokey(n_sync_obj * sizeof(rw_lock_t)));

      for (ulint i = 0; i < n_sync_obj; i++) {
        rw_lock_create(hash_table_locks_key, table->sync_obj.rw_locks + i,
                       level);
      }

      break;
    }

    case HASH_TABLE_SYNC_NONE:
      ut_error;
  }

  table->n_sync_obj = n_sync_obj;
}
#endif /* !UNIV_HOTBACKUP */