Tagged with "mysql"

Fun MySQL fact of the day: ROW format

Over the last couple weeks, all of the examples we've considered have used the STATEMENT binary log format. We've also discussed, no less than two times, that the STATEMENT format is prone to incorrect results for non-deterministic DML (Data Manipulation Language) statements, and last Friday, we considered the ROW ... read more

Fun MySQL fact of the day: unsafe logging

Over the last couple weeks, we've been discussing the MySQL binary log and building up our mental mode around the STATEMENT-based binary log format. When using a STATEMENT binary log format, MySQL very simply puts the SQL statement that issued a change into the binary log. Then, when we ... read more

Fun MySQL fact of the day: replication lag can be good

We've spent number of days discussing replication delay, and we've mostly considered replication delay as bad. And, true, in most cases, it usually is pretty bad, but today we're going to consider a case when replication delay is as desirable as it is important. ... read more

Fun MySQL fact of the day: absolute delay

Yesterday, we established an understanding of Seconds_Behind_Master and identified some of its shortcomings. While it's not a completely useless metric, it's also not a very helpful one. What we probably really want is an absolute measure of replication latency, and we'll look at one way of accomplishing that today. ... read more

Fun MySQL fact of the day: the SQL thread

Yesterday, we looked at how a MySQL replica's IO thread downloads a master's binary logs and stores them as its own "relay logs". We also said this happens until the IO thread is stopped or the replica database runs out of disk space, and while that's true, there's another ... read more
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