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f577d864cd
when high concurrency": remove HASH::current_record and make it
an external search parameter, so that it can not be the cause of a
race condition under high concurrent load.
The bug was in a race condition in table_hash_search,
when column_priv_hash.current_record was overwritten simultaneously
by multiple threads, causing the search for a suitable grant record
to fail.
No test case as the bug is repeatable only under concurrent load.
include/hash.h:
- remove current_record from HASH, instead modify hash_first,
hash_next to accept HASH_SEARCH_STATE as an IN/OUT parameter
mysys/hash.c:
- remove HASH::current_record
- change declarations of functions that use HASH in read-only mode
to accept const HASH * instead of HASH *.
- implement hash_search; move the old implementation of hash_search
to hash_first
mysys/testhash.c:
- adjust the test case to changed function declarations
sql/lock.cc:
- adjust to changed declarations of hash_search, hash_next
sql/sql_acl.cc:
- adjust to changed declarations of hash_search, hash_next
sql/sql_base.cc:
- adjust to changed declarations of hash_search, hash_nex
sql/sql_cache.cc:
- adjust to a changed declaration of hash_replace
72 lines
2.5 KiB
C
72 lines
2.5 KiB
C
/* Copyright (C) 2000 MySQL 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; either version 2 of the License, or
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(at your option) any later version.
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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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/* Dynamic hashing of record with different key-length */
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#ifndef _hash_h
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#define _hash_h
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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Overhead to store an element in hash
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Can be used to approximate memory consumption for a hash
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*/
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#define HASH_OVERHEAD (sizeof(char*)*2)
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typedef byte *(*hash_get_key)(const byte *,uint*,my_bool);
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typedef void (*hash_free_key)(void *);
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typedef struct st_hash {
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uint key_offset,key_length; /* Length of key if const length */
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uint records, blength;
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uint flags;
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DYNAMIC_ARRAY array; /* Place for hash_keys */
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hash_get_key get_key;
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void (*free)(void *);
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CHARSET_INFO *charset;
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} HASH;
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/* A search iterator state */
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typedef uint HASH_SEARCH_STATE;
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#define hash_init(A,B,C,D,E,F,G,H) _hash_init(A,B,C,D,E,F,G, H CALLER_INFO)
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my_bool _hash_init(HASH *hash, CHARSET_INFO *charset,
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uint default_array_elements, uint key_offset,
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uint key_length, hash_get_key get_key,
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void (*free_element)(void*), uint flags CALLER_INFO_PROTO);
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void hash_free(HASH *tree);
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void my_hash_reset(HASH *hash);
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byte *hash_element(HASH *hash,uint idx);
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gptr hash_search(const HASH *info, const byte *key, uint length);
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gptr hash_first(const HASH *info, const byte *key, uint length,
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HASH_SEARCH_STATE *state);
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gptr hash_next(const HASH *info, const byte *key, uint length,
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HASH_SEARCH_STATE *state);
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my_bool my_hash_insert(HASH *info,const byte *data);
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my_bool hash_delete(HASH *hash,byte *record);
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my_bool hash_update(HASH *hash,byte *record,byte *old_key,uint old_key_length);
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void hash_replace(HASH *hash, HASH_SEARCH_STATE *state, byte *new_row);
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my_bool hash_check(HASH *hash); /* Only in debug library */
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#define hash_clear(H) bzero((char*) (H),sizeof(*(H)))
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#define hash_inited(H) ((H)->array.buffer != 0)
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#ifdef __cplusplus
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}
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#endif
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#endif
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