diff options
Diffstat (limited to 'sql/mysqld.cc')
| -rw-r--r-- | sql/mysqld.cc | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/sql/mysqld.cc b/sql/mysqld.cc index a28ae38c675..ad2b6c5fd68 100644 --- a/sql/mysqld.cc +++ b/sql/mysqld.cc @@ -432,6 +432,7 @@ char server_version[SERVER_VERSION_LENGTH]; char *mysqld_unix_port, *opt_mysql_tmpdir; const char **errmesg; /* Error messages */ const char *myisam_recover_options_str="OFF"; +const char *myisam_stats_method_str="nulls_inequal"; /* name of reference on left espression in rewritten IN subquery */ const char *in_left_expr_name= "<left expr>"; /* name of additional condition */ @@ -4358,6 +4359,7 @@ enum options_mysqld OPT_MAX_ERROR_COUNT, OPT_MULTI_RANGE_COUNT, OPT_MYISAM_DATA_POINTER_SIZE, OPT_MYISAM_BLOCK_SIZE, OPT_MYISAM_MAX_EXTRA_SORT_FILE_SIZE, OPT_MYISAM_MAX_SORT_FILE_SIZE, OPT_MYISAM_SORT_BUFFER_SIZE, + OPT_MYISAM_STATS_METHOD, OPT_NET_BUFFER_LENGTH, OPT_NET_RETRY_COUNT, OPT_NET_READ_TIMEOUT, OPT_NET_WRITE_TIMEOUT, OPT_OPEN_FILES_LIMIT, @@ -5513,6 +5515,11 @@ The minimum value for this variable is 4096.", (gptr*) &global_system_variables.myisam_sort_buff_size, (gptr*) &max_system_variables.myisam_sort_buff_size, 0, GET_ULONG, REQUIRED_ARG, 8192*1024, 4, ~0L, 0, 1, 0}, + {"myisam_stats_method", OPT_MYISAM_STATS_METHOD, + "Specifies how MyISAM index statistics collection code should threat NULLs. " + "Possible values of name are \"nulls_inequal\" (default behavior for 4.1/5.0), and \"nulls_equal\" (emulate 4.0 behavior).", + (gptr*) &myisam_stats_method_str, (gptr*) &myisam_stats_method_str, 0, + GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0}, {"net_buffer_length", OPT_NET_BUFFER_LENGTH, "Buffer length for TCP/IP and socket communication.", (gptr*) &global_system_variables.net_buffer_length, @@ -6096,6 +6103,7 @@ static void mysql_init_variables(void) query_id= thread_id= 1L; strmov(server_version, MYSQL_SERVER_VERSION); myisam_recover_options_str= sql_mode_str= "OFF"; + myisam_stats_method_str= "nulls_inequal"; my_bind_addr = htonl(INADDR_ANY); threads.empty(); thread_cache.empty(); @@ -6144,6 +6152,12 @@ static void mysql_init_variables(void) global_system_variables.max_join_size= (ulonglong) HA_POS_ERROR; max_system_variables.max_join_size= (ulonglong) HA_POS_ERROR; global_system_variables.old_passwords= 0; + + /* + Default behavior for 4.1 and 5.0 is to treat NULL values as inequal + when collecting index statistics for MyISAM tables. + */ + global_system_variables.myisam_stats_method= MI_STATS_METHOD_NULLS_NOT_EQUAL; /* Variables that depends on compile options */ #ifndef DBUG_OFF @@ -6753,6 +6767,16 @@ get_one_option(int optid, const struct my_option *opt __attribute__((unused)), fprintf(stderr, "Unknown option to tc-heuristic-recover: %s\n",argument); exit(1); } + case OPT_MYISAM_STATS_METHOD: + { + myisam_stats_method_str= argument; + int method; + if ((method=find_type(argument, &myisam_stats_method_typelib, 2)) <= 0) + { + fprintf(stderr, "Invalid value of myisam_stats_method: %s.\n", argument); + exit(1); + } + global_system_variables.myisam_stats_method= method; break; } case OPT_SQL_MODE: |