Tagged with "mysql"

Fun MySQL fact of the day: redo logs

Over the last few weeks, we've considered how useful the MySQL binary log can be, but you may be thinking, "if the binary log doesn't get written until commit, how does MySQL undo a transaction if it crashes?". And, well, if you remember back through March and April ... read more

Fun MySQL fact of the day: group commit

We now know that each MySQL thread has its own binary log cache to which it writes the binary log events for a single transaction. We also briefly discussed that MySQL will, upon commit of a transaction, write the thread's binary log cache to the actual binary log file ... read more

Fun MySQL fact of the day: binlog cache overflow

Yesterday, we started to consider how MySQL writes its binary log file, and we started to look at how MySQL uses a per-thread binary log cache, which, by default, is 32KB. Depending on your systems' access patterns, however, 32KB may seem rather small. For example, what if you frequently update ... read more

Fun MySQL fact of the day: binlog cache

By now, I think we have a shared understanding that the binary log is an important feature in MySQL. And maybe, you may have been wondering, "how does the binary log get recorded"? And that's a good question with a couple fun facts we'll look at next! ... read more

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 ... 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 ... read more
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