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107 lines
2.8 KiB
C
107 lines
2.8 KiB
C
/* Copyright (c) 2003, 2011, Oracle and/or its affiliates.
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Copyright (c) 2010, 2011, Monty Program Ab
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
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/*
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Handling of multiple key caches
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The idea is to have a thread safe hash on the table name,
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with a default key cache value that is returned if the table name is not in
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the cache.
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*/
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#include "mysys_priv.h"
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#include <keycache.h>
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#include <hash.h>
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#include <m_string.h>
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#include "my_safehash.h"
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/*****************************************************************************
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Functions to handle the key cache objects
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*****************************************************************************/
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/* Variable to store all key cache objects */
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static SAFE_HASH key_cache_hash;
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my_bool multi_keycache_init(void)
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{
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return safe_hash_init(&key_cache_hash, 16, (uchar*) dflt_key_cache);
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}
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void multi_keycache_free(void)
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{
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safe_hash_free(&key_cache_hash);
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}
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/*
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Get a key cache to be used for a specific table.
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SYNOPSIS
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multi_key_cache_search()
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key key to find (usually table path)
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uint length Length of key.
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def Default value if no key cache
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NOTES
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This function is coded in such a way that we will return the
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default key cache even if one never called multi_keycache_init.
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This will ensure that it works with old MyISAM clients.
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RETURN
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key cache to use
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*/
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KEY_CACHE *multi_key_cache_search(uchar *key, uint length,
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KEY_CACHE *def)
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{
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if (!key_cache_hash.hash.records)
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return def;
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return (KEY_CACHE*) safe_hash_search(&key_cache_hash, key, length,
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(void*) def);
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}
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/*
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Assosiate a key cache with a key
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SYONOPSIS
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multi_key_cache_set()
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key key (path to table etc..)
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length Length of key
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key_cache cache to assococite with the table
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NOTES
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This can be used both to insert a new entry and change an existing
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entry
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*/
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my_bool multi_key_cache_set(const uchar *key, uint length,
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KEY_CACHE *key_cache)
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{
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return safe_hash_set(&key_cache_hash, key, length, (uchar*) key_cache);
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}
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void multi_key_cache_change(KEY_CACHE *old_data,
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KEY_CACHE *new_data)
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{
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safe_hash_change(&key_cache_hash, (uchar*) old_data, (uchar*) new_data);
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}
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