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WL#5151: Conversion between different types when replicating

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Row-based replication requires the types of columns on the
master and slave to be approximately the same (some safe
conversions between strings are allowed), but does not
allow safe conversions between fields of similar types such
as TINYINT and INT.

This patch implement type conversions between similar fields
on the master and slave.

The conversions are controlled using a new variable
SLAVE_TYPE_CONVERSIONS of type SET('ALL_LOSSY','ALL_NON_LOSSY').

Non-lossy conversions are any conversions that do not run the
risk of losing any information, while lossy conversions can
potentially truncate the value. The column definitions are
checked to decide if the conversion is acceptable.

If neither conversion is enabled, it is required that the
definitions of the columns are identical on master and slave.

Conversion is done by creating an internal conversion table,
unpacking the master data into it, and then copy the data to
the real table on the slave.
This commit is contained in:
Mats Kindahl
2009-12-14 12:04:55 +01:00
parent c7a02cf807
commit c63df11f37
39 changed files with 2893 additions and 464 deletions
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23
sql/mysqld.cc
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@ -525,6 +525,8 @@ ulong open_files_limit, max_binlog_size, max_relay_log_size;
ulong slave_net_timeout, slave_trans_retries;
ulong slave_exec_mode_options;
const char *slave_exec_mode_str= "STRICT";
ulong slave_type_conversions_options;
const char *slave_type_conversions_default= "";
ulong thread_cache_size=0, thread_pool_size= 0;
ulong binlog_cache_size=0;
ulonglong max_binlog_cache_size=0;
@ -5690,6 +5692,7 @@ enum options_mysqld
#endif /* defined(ENABLED_DEBUG_SYNC) */
OPT_OLD_MODE,
OPT_SLAVE_EXEC_MODE,
OPT_SLAVE_TYPE_CONVERSIONS,
OPT_GENERAL_LOG_FILE,
OPT_SLOW_QUERY_LOG_FILE,
OPT_IGNORE_BUILTIN_INNODB
@ -6413,6 +6416,15 @@ replicating a LOAD DATA INFILE command.",
{"slave-exec-mode", OPT_SLAVE_EXEC_MODE,
"Modes for how replication events should be executed. Legal values are STRICT (default) and IDEMPOTENT. In IDEMPOTENT mode, replication will not stop for operations that are idempotent. In STRICT mode, replication will stop on any unexpected difference between the master and the slave.",
(uchar**) &slave_exec_mode_str, (uchar**) &slave_exec_mode_str, 0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
{"slave-type-conversions", OPT_SLAVE_TYPE_CONVERSIONS,
"Set of slave type conversions that are enabled. Legal values are:"
" ALL_LOSSY to enable lossy conversions and"
" ALL_NON_LOSSY to enable non-lossy conversions."
" If the variable is assigned the empty set, no conversions are"
" allowed and it is expected that the types match exactly.",
(uchar**) &slave_type_conversions_default,
(uchar**) &slave_type_conversions_default,
0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
#endif
{"slow-query-log", OPT_SLOW_LOG,
"Enable|disable slow query log", (uchar**) &opt_slow_log,
@ -7671,6 +7683,11 @@ static int mysql_init_variables(void)
slave_exec_mode_options= (uint)
find_bit_type_or_exit(slave_exec_mode_str, &slave_exec_mode_typelib, NULL,
&error);
/* Slave type conversions */
slave_type_conversions_options= 0;
slave_type_conversions_options=
find_bit_type_or_exit(slave_type_conversions_default, &slave_type_conversions_typelib,
NULL, &error);
if (error)
return 1;
opt_specialflag= SPECIAL_ENGLISH;
@ -7900,6 +7917,12 @@ mysqld_get_one_option(int optid,
if (error)
return 1;
break;
case OPT_SLAVE_TYPE_CONVERSIONS:
slave_type_conversions_options= (uint)
find_bit_type_or_exit(argument, &slave_type_conversions_typelib, "", &error);
if (error)
return 1;
break;
#endif
case OPT_SAFEMALLOC_MEM_LIMIT:
#if !defined(DBUG_OFF) && defined(SAFEMALLOC)