When talking about the benefits and use cases of ProxySQL with clients, one feature I generally reference is the query rewrite engine. This is a great feature that is often used for sharding (I’ve written about this in the past at Horizontal Scaling in MySQL – Sharding Followup). Another use case I reference is “temporary application fixes.” While this is definitely a valid use case, I hadn’t personally come across an issue in the wild where the application fix wasn’t trivial.
Recently, a client hit a case where pt-archiver wasn’t able to archive rows from a table that had a bit column as part of a primary key. This is certainly an edge case, but we had hoped the fix was trivial. Unfortunately, the root of the issue was around how the Perl DBI library quotes and handles the bit data type by default.
When …
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