Zero is a big number
I made changes to mk-query-digest yesterday that I didn’t expect to cause any adverse affects. On the contrary, several tests began to fail because a single new but harmless line began to appear in the...
View ArticleDebugging and ripple effects
Like I said earlier, every tiny change that the test suite reveals after code changes is significant. I caught a very subtle “bug” today in recent changes to mk-query-digest (a.k.a. mqd). If you like...
View ArticleDown the rabbit hole
Generally I avoid going down rabbit holes but today I decided to see how deep a particular testing rabbit hole went. This post is a third in what seems be a continuing series of programming anecdotes....
View ArticleNew algorithm for calculating 95 percentile
The 95 percentile for query response times is and old concept; Peter and Roland blogged about it in 2008. Since then, MySQL tools have calculated the 95 percentile by collecting all values, either...
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