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e80537b791
A Query in the MyISAM merge table was crashing
if the index merge algorithm was being used
Index Merge optimization requires the reading of
multiple indexes at the same time. Reading multiple
indexes at once with current SE API means that we
need to have handler instance for each to-be-read
index. This is done by creating clones of the handlers
instances. The clone internally does a open of the handler.
The open for a MERGE engine is handled in the following
phases
1) open parent table
2) generate list of underlying
table
3) attach underlying tables
But the current implementation does only the first
phase (i.e.) open parent table.
The current patch fixes this at the MERGE engine level,
by handling the clone operation within the MERGE engine
rather than in the storage engine API. It opens and
attaches the MyISAM tables on the MyISAM storage engine
interface directly within the MERGE engine. The new MyISAM
table instances, as well as the MERGE clone itself, are not
visible in the table cache. This is not a problem because
all locking is handled by the original MERGE table from which
this is cloned of.
mysql-test/r/merge.result:
updated the result file to reflect the new tests
added to test the fix
mysql-test/t/merge.test:
Added new tests to verify that the index merge
algorithm does not crash in the merge engine.
storage/myisammrg/ha_myisammrg.cc:
Implement the clone method, that handles
1) Cloning the handler
2) Opening underlying MYISAM child tables
3) Copies the state of the original handler and the children
into the cloned instances
4) Sets the appropriate flags
storage/myisammrg/ha_myisammrg.h:
Added a flag that is set to indicate that the current
instance is cloned. Also added the prototype or the clone
method.
storage/myisammrg/myrg_open.c:
Since we do now again use myrg_open() in the server
removed the comments marking this as deadcode.
101 lines
4.1 KiB
C++
101 lines
4.1 KiB
C++
/* Copyright (C) 2000-2006 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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#ifdef USE_PRAGMA_INTERFACE
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#pragma interface /* gcc class implementation */
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#endif
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/* class for the the myisam merge handler */
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#include <myisammrg.h>
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class ha_myisammrg: public handler
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{
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MYRG_INFO *file;
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my_bool is_cloned; /* This instance has been cloned */
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public:
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TABLE_LIST *next_child_attach; /* next child to attach */
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uint test_if_locked; /* flags from ::open() */
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bool need_compat_check; /* if need compatibility check */
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ha_myisammrg(handlerton *hton, TABLE_SHARE *table_arg);
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~ha_myisammrg();
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const char *table_type() const { return "MRG_MyISAM"; }
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const char **bas_ext() const;
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const char *index_type(uint key_number);
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ulonglong table_flags() const
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{
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return (HA_REC_NOT_IN_SEQ | HA_AUTO_PART_KEY | HA_NO_TRANSACTIONS |
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HA_BINLOG_ROW_CAPABLE | HA_BINLOG_STMT_CAPABLE |
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HA_NULL_IN_KEY | HA_CAN_INDEX_BLOBS | HA_FILE_BASED |
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HA_ANY_INDEX_MAY_BE_UNIQUE | HA_CAN_BIT_FIELD |
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HA_HAS_RECORDS |
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HA_NO_COPY_ON_ALTER);
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}
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ulong index_flags(uint inx, uint part, bool all_parts) const
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{
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return ((table_share->key_info[inx].algorithm == HA_KEY_ALG_FULLTEXT) ?
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0 : HA_READ_NEXT | HA_READ_PREV | HA_READ_RANGE |
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HA_READ_ORDER | HA_KEYREAD_ONLY);
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}
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uint max_supported_keys() const { return MI_MAX_KEY; }
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uint max_supported_key_length() const { return MI_MAX_KEY_LENGTH; }
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uint max_supported_key_part_length() const { return MI_MAX_KEY_LENGTH; }
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double scan_time()
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{ return ulonglong2double(stats.data_file_length) / IO_SIZE + file->tables; }
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int open(const char *name, int mode, uint test_if_locked);
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int attach_children(void);
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int detach_children(void);
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virtual handler *clone(MEM_ROOT *mem_root);
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int close(void);
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int write_row(uchar * buf);
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int update_row(const uchar * old_data, uchar * new_data);
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int delete_row(const uchar * buf);
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int index_read_map(uchar *buf, const uchar *key, key_part_map keypart_map,
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enum ha_rkey_function find_flag);
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int index_read_idx_map(uchar *buf, uint index, const uchar *key,
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key_part_map keypart_map,
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enum ha_rkey_function find_flag);
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int index_read_last_map(uchar *buf, const uchar *key, key_part_map keypart_map);
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int index_next(uchar * buf);
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int index_prev(uchar * buf);
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int index_first(uchar * buf);
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int index_last(uchar * buf);
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int index_next_same(uchar *buf, const uchar *key, uint keylen);
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int rnd_init(bool scan);
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int rnd_next(uchar *buf);
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int rnd_pos(uchar * buf, uchar *pos);
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void position(const uchar *record);
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ha_rows records_in_range(uint inx, key_range *min_key, key_range *max_key);
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int info(uint);
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int reset(void);
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int extra(enum ha_extra_function operation);
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int extra_opt(enum ha_extra_function operation, ulong cache_size);
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int external_lock(THD *thd, int lock_type);
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uint lock_count(void) const;
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int create(const char *name, TABLE *form, HA_CREATE_INFO *create_info);
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THR_LOCK_DATA **store_lock(THD *thd, THR_LOCK_DATA **to,
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enum thr_lock_type lock_type);
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void update_create_info(HA_CREATE_INFO *create_info);
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void append_create_info(String *packet);
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MYRG_INFO *myrg_info() { return file; }
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TABLE *table_ptr() { return table; }
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bool check_if_incompatible_data(HA_CREATE_INFO *info, uint table_changes);
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int check(THD* thd, HA_CHECK_OPT* check_opt);
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ha_rows records();
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};
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