…know it is not MySQL problem, might be even not problem with your MySQL configuration, queries and hardware, even…too high Many developers will test script with multiple level of concurrency and find out doing … This is true if you have system completely at your disposal. If you however need system …
Post: What would make MySQL Multiple Queries Usable ?
September 5, 2007 By 1 Comment
MySQL Has API to run Multiple Queries at once. This feature was designed mainly with saving network round trip …. What would make MySQL Multiple Queries API more usable ? Allow to run queries in parallel – The great benefit of knowning all queries at once is of course…
Post: MySQL Server Memory Usage
May 17, 2006 By 18 Comments
… threads. Each thread connecting to MySQL server will needs its own buffers. About 256K is allocated at once even if thread is idle… the need and freed once given stage of query is done. Some of them are allocated as single chunk at once others, for example… maximum amount of memory MySQL will allocate for this operation. Note it is more complicated than once may think – multiple buffers of the…
Post: MySQL Query Cache
July 27, 2006 By 69 Comments
… statements and cursors Query Cache works with query text and want full result set at once. In prepared statements there is query with placeholders and… all queries derived from this table are invalidated at once. Most of them quite likely would not have change their result set but MySQL… shared memory. It can’t retrieve multiple objects at the same time You have to query cache object by object which adds latency…
Post: MySQL Prepared Statements
August 2, 2006 By 19 Comments
…you execute query only once extra round trip to the server will be required, or because query cache …connection or multiple connections. Do not forget to close prepared statements – Many memory leaks reported in MySQL … limits how many statements can be open at the same time to avoid overload. Check …
Post: Should we give a MySQL Query Cache a second chance ?
April 10, 2011 By 63 Comments
… with MySQL Query Cache so it once again is appealing to improve performance for MySQL Applications ? Make it Lockless Can we re-implement MySQL Query Cache…, at least we can use same “cheat” as MySQL 5.5 uses for Innodb Buffer Pool and have multiple MySQL Query Cache instances hashed by query…
Post: How multiple disks can benefit for single client workload ?
April 26, 2008 By 4 Comments
…understand if MySQL goes through more rows than it needs to requires look at the queries and… multiple hard drives does not help if you have single query (or stream of queries) …queries. After pages are fetched and modified they need to be written to the disk, this however does not happen at once…
Post: Shard-Query turbo charges Infobright community edition (ICE)
May 6, 2011 By 22 Comments
… of queries against a MySQL database by distributing the work over multiple machines and/or multiple cores…query. The queries should be self-explanatory. Performance, at a glance You will notice that Shard-Query… “scale-up” and “scale-out”, but once again, the “scale-out” results are the most…
Post: Slow Query Log analyzes tools
September 6, 2006 By 83 Comments
…multiple passes across same slow query log first to fix worse queries and then come to find more optimization candidates. So “tail -f mysql…only slow queries will be looked at. The …queries. Once you have created full log – parse it and check queries using EXPLAIN starting from most impacted onces…
Comment: Beware of MyISAM Key Cache mutex contention
January 12, 2010 By 10 Comments
… 120 load average, mysql master restart needed and apache servers as well. At first I did standard tuning and query tuning but it… parameters I could think of, and mysql processes showed in issue periods multiple copies of the same query, sometimes with also same parameters… said. Still, Still! Sometimes we get 20/30 parallel identical queries at once that can raise the load to 8, and of course…
