… plus in many cases you can use result overload to make MySQL to consume so much memory so it will swap badly until… memory consumed by single prepared statement you can create statement with thousands of placeholders and send data for each of them using mysql… having few connections which use appropriate operations heavily you can reduce system performance beyond being functional. General Overload As MySQL does not have…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 141 Comments
… show benefit from using indexes. In fact even MySQL optimizer currently does not take it into account. For In memory workload index accesses… big scans. This will reduce the gap but I doubt it will be closed. Joins Joins are used to compose the complex… with in memory – Processing in memory is so much faster and you have whole bunch of problems solved just doing so. Use multiple…
Post: Should you have your swap file enabled while running MySQL ?
April 6, 2008 By 31 Comments
… to manage memory smarter knowing it does not need to look for pages to swap out or balance memory for reducing a cache… temporary tables and so MySQL running out of memory (and getting killed by kernel). It could not even be MySQL but some script… with /proc/sys/vm/swappiness =0. You can lock MySQL in memory by using –memlock option but it opens its own can of…
Post: MySQL Performance on Memory Appliance
March 31, 2008 By 23 Comments
… out MySQL Performance on “Memory Appliance” by Violin Memory which can be used as extremely high speed storage system. I helped Violin Memory to optimize MySQL… MyISAM with myisam_use_mmap option which did not seems to give any significant performance benefit, may be even reducing performance few…
Post: MySQL performance on EC2/EBS versus RDS
August 4, 2011 By 11 Comments
… not always great. There are specific use cases in which it’s …reduced mutex contention. The performance improvements I got with Percona Server were similar to the performance improvements I saw versus stock MySQL… database design influences greatly how much memory and disk resources are required. The…
Post: MySQL Prepared Statements
August 2, 2006 By 21 Comments
… used in textual protocol, which not only consumed time but also required extra memory consumption both on server and client. So in MySQL… most of the time in this case. It could also reduce performance in certain cases because if you execute query only…. Do not forget to close prepared statements – Many memory leaks reported in MySQL Server turned out to be prepare statements or cursors…
Post: MySQL EXPLAIN limits and errors.
July 24, 2006 By 6 Comments
… other reason for difference is join_buffer which reduces number of passes MySQL had to perform and so number of row combinations… information about using disk for sort or temporary tables MySQL always calls it “filesort” even if it is done in memory. Also it… BLOB fields can’t work with in memory temporary table. The other thing – since MySQL 4.1 sorting can be done with…
Post: MySQL caching methods and tips
April 4, 2011 By 5 Comments
…results, then place them into the cache. Additionally, memory pressure may cause unexpected invalidation of items, …not accessed very frequently. Use what you need Both Memcached and the MySQL query cache are limited in…, this can be very beneficial as may reduce the number of instances you need. Don’…
Post: State of MySQL Market and will Replication live ?
April 9, 2008 By 29 Comments
… of 90s when MySQL appeared on the market many web applications were simple and often not using database at all. MySQL did not… Wave is appliances – you can see Violin Memory appliance which can be used with MySQL to get very fast IO and so consolidate… the scale of Big Table with Map Reduce. Indeed I think MySQL Replication usage will reduce, but I would not expect Memcached to…
Post: MySQL Crash Recovery
July 30, 2006 By 30 Comments
… system extremely slow and also can use up all allowed connections or run out of memory ( myisam_sort_buffer_size is normally set pretty lage). If this becomes the problem I use tiny script… dictionary may cause MySQL to fail with wierd error messages. In MySQL 4.1 sync_frm option was added which reduces this problem…
