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Search Results for: set table cache

Percona XtraDB Cluster – installation and setup webinar follow up Q&A

Thanks for all, who attended my webinar, I got many questions and I wanted to take this opportunity to answer them. Q: Even ntp has a delay of 0.3-0.4 between servers does that mean a …

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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 …

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ALTER TABLE: Creating Index by Sort and Buffer Pool Size

Today I was looking at the ALTER TABLE performance with fast index creation and without it with different buffer pool sizes. Results are pretty interesting. I used modified Sysbench table for these tests because original …

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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 …

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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 …

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How well does your table fits in innodb buffer pool ?

Understanding how well your tables and indexes fit to buffer pool are often very helpful to understand why some queries are IO bound and others not – it may be because the tables and indexes …

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More on dangers of the caches

I wrote couple of weeks ago on dangers of bad cache design. Today I’ve been troubleshooting the production down case which had fair amount of issues related to how cache was used. The deal was …

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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 …

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FlashCache: more benchmarks

Previously I covered simple case with FlashCache, when data fits into cache partitions, now I am trying to test when data is bigger than cache. But before test setup let me address some concern (which …

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FlashCache: first experiments

I wrote about FlashCache there, and since that I run couple benchmarks, to see what performance benefits we can expect. For initial tries I took sysbench oltp tests ( read-only and read-write) and case when …

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