I very much like the fact that MySQL allows you to embed comments into SQL statements. These comments are extremely convenient, because they are written into MySQL log files as part of the query. This includes the general log, the binary log and the slow query log. Maatkit includes tools which interact with these logs, including mk-query-digest. This tool, in particular, has a very nice option called --embedded-attributes which can process data embedded in query comments.
The support for embedded attributes makes some cool tricks possible. Peter and I co-presented a talk at this past MySQL Conference and Expo. In this talk I presented my Instrumentation-for-PHP class as a demonstration …
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