Invalidating query cache entries replication Females who want to meet for sex sydney chat site

Posted by / 01-Sep-2020 23:54

Invalidating query cache entries replication

After review, it may be pushed to the relevant source trees for release in the next version.

You can access the patch from: 2735 Kristofer Pettersson 2008-09-08 Bug#38551 query cache can still consume [very little] cpu time even when it is off.

Query Cache::invalidate_table locks the query cache, invalidates the QC if query_cache_size 0, unlocks QC and returns.

The current code actually locks/unlocks the query_cache lock twice when the query_cache_size is zero! This can all be bypassed if the check for query_cache_size is done without holding the QC lock as in Query_cache::store_query The CPU time wasted is very less, however, in benchmark situations, every cpu cycle counts.

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. When creating a test table in server 4, checking the relay log in server 1 shows the create statement was copied to the relay log in server 1 instantly, but the table is not created. Servers 1 2 & 4 were having "invalidating query cache entries (table)" stuck in their replication thread.

By using the command line option --query_cache_type=0, the user can disable the query cache permanently and avoid taking the query cache mutex. After review, it may be pushed to the relevant source trees for release in the next version. After review, it may be pushed to the relevant source trees for release in the next version.However, the Query Cache still does some work before finding out that query_cache_size is 0 and returning.For example, Query Cache::invalidate() builds up a list of tables used, and calls Query Cache::invalidate_table().Updated changelog entry: The server unnecessarily acquired a query cache mutex even with the query cache disabled, resulting in a small performance decrement.Now if the server is started with query_cache_type set to 0, it does not acquire the query cache mutex.

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This has the implication that the query cache cannot be enabled at runtime. After review, it may be pushed to the relevant source trees for release in the next version.