Sync_replication?

[tillermanwork]

I was recently using MySQL replication and was testing an unclean shutdown of the system(e.g pulling out the power cable) when I discovered that MySQL will lose a small amount of data that has not yet been flushed to disk. After browsing the manual, I discovered that the server variable sync_binlog can be set to 1 to cause the binary log to flush after every update to a table.

Now using this, I was able to get the replication setup (and the Master server, too) to correctly keep all records, however with this approach I have taken a rather large hit to performance.

Now, while attempting this on a MySQL 5.0 server, when performing a SHOW VARIABLES command, I noticed the following variables:

sync_replication | 0
sync_replication_slave_id | 0
sync_replication_timeout | 10

I have looked through the manual and even tried google with no success as to what these variables represent. Does anyone have any idea what these do?

Would it be possible to setup MySQL replication in such a way that replication is performed immediately, as each request comes in, yet the binary file is only synched at a rate that yields high performance? This seems possible to achieve (at least in theory), so I am wondering if these variables could possibly be related in some way?