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Search Results for: enable query cache

The MySQL Query Cache: How it works, plus workload impacts (good and bad)

Query caching is one of the prominent features in MySQL and a vital part of query optimization. It is important to know how it works as it has the potential to cause significant performance improvements – …


Tools and tips for analysis of MySQL’s Slow Query Log

MySQL has a nice feature, slow query log, which allows you to log all queries that exceed a predefined about of time to execute. Peter Zaitsev first wrote about this back in 2006 – there …


Advanced MySQL Query Tuning: Webinar followup Q&A

Thanks to all who attended my “MySQL Query Tuning” webinar on July 24.  If you missed it, you can you can download the slides and also watch the recorded video. Thank you for the excellent …


Virident vCache vs. FlashCache: Part 2

This is the second part in a two-part series comparing Virident’s vCache to FlashCache. The first part was focused on usability and feature comparison; in this post, we’ll look at some sysbench test results. Disclosure: …


Write contentions on the query cache

While doing a performance audit for a customer a few weeks ago, I tried to improve the response time of their top slow query according to pt-query-digest‘s report. This query was run very frequently and …


Identifying the load with the help of pt-query-digest and Percona Server

Overview Profiling, analyzing and then fixing queries is likely the most oft-repeated part of a job of a DBA and one that keeps evolving, as new features are added to the application new queries pop …


MySQL opening .frm even when table is in table definition cache

or… “the case of Stewart recognizing parameters to the read() system call in strace output”. Last week, a colleague asked a question: I have an instance of MySQL with 100 tables and the table_definition_cache set …


Should we give a MySQL Query Cache a second chance ?

Over last few years I’ve been suggesting more people to disable Query Cache than to enable it. It can cause contention problems as well as stalls and due to coarse invalidation is not as efficient …


Flexviews – part 3 – improving query performance using materialized views

Combating “data drift” In my first post in this series, I described materialized views (MVs). An MV is essentially a cached result set at one point in time. The contents of the MV will become …


mk-query-digest, query comments and the query cache

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 …