mysql - do locks propagate over replication?

Question

I have a Mysql master-slave(s) replication with MyISAM tables. All updates are done on the master and selects are done on either the master or slaves. It appears that we might need to manually lock a few tables when we do certain updates. While this write lock is on the tables, no selects can happen on the locked table. But what about on the slaves? Does the lock propagate out? Say I have table_A and table_B. I initiate a lock on table_A and table_B on the master and start performing the update. At this time no other connection can read table_A and table_B off the master? But what if at this time another connection tries to read the tables off of a slave, can they do so?

Accepted Answer

Everything that MySQL replicates can be found in the binary logs.

You can run the following command to see the details.

```
show global variables like 'log_bin%';
```

log_bin_basename will tell you the path to your binary logs with base file name.

and run

```
show binary logs
```

to find the binary files that are currently present on your server.

You can check the actual commands that are written to the file by using `mysqlbinlog` command together with the file name or by running `show binlog events ...` from the MySQL CLI.

Also, check what binlog_format are you using.

Basically - the lock of the tables is not directly propagated to slaves, but at the time, whey will execute the performed updates they will perform a lock of the updated table if needed.

mysql - do locks propagate over replication?

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