[Maria-docs] query cache at askmonty kb
Hi guys first, thanks greenman to review query cache article well i have some others doubts at query cache that i think should/could be better explained 1) Limitations - The query cache needs to be disabled in order to use OQGRAPH <https://mariadb.com/kb/en/oqgraph/> and, in older versions, Galera <https://mariadb.com/kb/en/galera/>. - The query cache is not used by the Spider <https://mariadb.com/kb/en/spider/> storage engine (amongst others). why qc must be disabled with oqgraph? what's the possible problems without disabling it? maybe examples are wellcome, since reading oqgraph information we only have: Installing See Installing OQGRAPH <https://mariadb.com/kb/en/installing-oqgraph/>. Note that the query cache <https://mariadb.com/kb/en/query-cache/> needs to be disabled for OQGRAPH to function correctly. Spider have some sql_cache/sql_no_cache features, maybe should be nice a feature table about what engine support and how it support 2) include something related to query cache lock problems 2.1) write content lock while inserting new queries 2.2) global lock "quering" query cache before query execution 2.3) maybe we could include some benchmarks since today we have only the "it's a feature that must be disabled", but when use a read intensive database (like a wordpress or something like it) it could be enabled 2.4) maybe some explain about good pratices with query cache and without query cache i think that's all =) thanks again -- Roberto Spadim
why qc must be disabled with oqgraph? what's the possible problems without disabling it? maybe examples are wellcome, since reading oqgraph information we only have: A comment at https://bugs.launchpad.net/oqgraph/+bug/796647 says that OQGraph does not know when the underlying table was changed and so is unable to notify mysql to invalidate its cached data. This leads to
Hi Roberto On 09/22/2014 04:18 PM, Roberto Spadim wrote: problems such as described at: https://mariadb.atlassian.net/browse/MDEV-5744, a bug I reported before I knew that the query cache had to be off, and before the engine declared itself not query-cache capable.
2) include something related to query cache lock problems 2.1) write content lock while inserting new queries 2.2) global lock "quering" query cache before query execution
2.3) maybe we could include some benchmarks since today we have only the "it's a feature that must be disabled", but when use a read intensive database (like a wordpress or something like it) it could be enabled 2.4) maybe some explain about good pratices with query cache and without query cache
Agree, these are good suggestions, I'll look at getting these documented at some point. ian
participants (2)
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Ian Gilfillan
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Roberto Spadim