mirror of
https://github.com/MariaDB/server.git
synced 2026-05-10 00:54:30 +02:00
5693b1e4a4
Normally, SET SESSION SQL_LOG_BIN is used by DBAs to run a non-conflicting command locally only, ensuring it does not get replicated. Setting GLOBAL SQL_LOG_BIN would not require all sessions to disconnect. When SQL_LOG_BIN is changed globally, it does not immediately take effect for any sessions. It takes effect by becoming the session-level default inherited at the start of each new session, and this setting is kept and cached for the duration of that session. Setting it intentionally is unlikely to have a useful effect under any circumstance; setting it unintentionally, such as while intending to use SET [SESSION] is potentially disastrous. Accidentally using SET GLOBAL SQL_LOG_BIN will not show an immediate effect to the user, instead not having the desired session-level effect, and thus causing other potential problems with local-only maintenance being binlogged and executed on slaves; And transactions from new sessions (after SQL_LOG_BIN is changed globally) are not binlogged and replicated, which would result in irrecoverable or difficult data loss. This is the regular GLOBAL variables way to work, but in replication context it does not look right on a working server (with connected sessions) 'set global sql_log_bin' and none of that connections is affected. Unexperienced DBA after noticing that the command did "nothing" will change the session var and most probably won't unset the global var, causing new sessions to not be binlog. Setting GLOBAL SQL_LOG_BIN allows DBA to stop binlogging on all new sessions, which can be used to make a server "replication read-only" without restarting the server. But this has such big requirements, stop all existing connections, that it is more likely to make a mess, it is too risky to allow the GLOBAL variable. The statement 'SET GLOBAL SQL_LOG_BIN=N' will produce an error in 5.5, 5.6 and 5.7. Reading the GLOBAL SQL_LOG_BIN will produce a deprecation warning in 5.7. |
||
|---|---|---|
| .. | ||
| binlog | ||
| engines | ||
| federated | ||
| funcs_1 | ||
| funcs_2 | ||
| innodb | ||
| innodb_zip | ||
| jp | ||
| large_tests | ||
| manual | ||
| parts | ||
| perfschema | ||
| perfschema_stress | ||
| rpl | ||
| stress | ||
| sys_vars | ||