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001829914b
Each time the server reloads privileges containing table grants, the system will allocate too much memory than needed because of badly chosen growth prediction in the underlying dynamic arrays. This patch introduces a new signature to the hash container initializer which enables a much more pessimistic approach in favour for more efficient memory useage. This patch was supplied by Google Inc. include/hash.h: * New signature for _hash_init. * Defined new function hash_init2 which takes growth_size argument. mysys/hash.c: * New signature for _hash_init. sql/sql_acl.cc: * Changed hash_init signature so that it takes a 'growth_size' smaller than the default. Each time a GRANT_TABLE is allocated a pre-allocated dynamic array is instantiated. A large growth size can result in too many unused hash-entries per table-entry and thus be a waste of free memory.
78 lines
2.8 KiB
C
78 lines
2.8 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; 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., 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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/* flags for hash_init */
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#define HASH_UNIQUE 1 /* hash_insert fails on duplicate key */
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typedef uchar *(*hash_get_key)(const uchar *,size_t*,my_bool);
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typedef void (*hash_free_key)(void *);
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typedef struct st_hash {
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size_t key_offset,key_length; /* Length of key if const length */
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size_t blength;
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ulong records;
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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,0,B,C,D,E,F,G,H CALLER_INFO)
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#define hash_init2(A,B,C,D,E,F,G,H,I) _hash_init(A,B,C,D,E,F,G,H,I CALLER_INFO)
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my_bool _hash_init(HASH *hash, uint growth_size,CHARSET_INFO *charset,
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ulong default_array_elements, size_t key_offset,
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size_t 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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uchar *hash_element(HASH *hash,ulong idx);
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uchar *hash_search(const HASH *info, const uchar *key, size_t length);
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uchar *hash_first(const HASH *info, const uchar *key, size_t length,
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HASH_SEARCH_STATE *state);
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uchar *hash_next(const HASH *info, const uchar *key, size_t length,
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HASH_SEARCH_STATE *state);
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my_bool my_hash_insert(HASH *info,const uchar *data);
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my_bool hash_delete(HASH *hash,uchar *record);
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my_bool hash_update(HASH *hash,uchar *record,uchar *old_key,size_t old_key_length);
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void hash_replace(HASH *hash, HASH_SEARCH_STATE *state, uchar *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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#define hash_init_opt(A,B,C,D,E,F,G,H) \
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(!hash_inited(A) && _hash_init(A,0,B,C,D,E,F,G, H CALLER_INFO))
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#ifdef __cplusplus
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}
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#endif
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#endif
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