…table = 1 ## Disabling query cache query_cache_size = 0 query_cache_type = 0 … NULL, PRIMARY KEY (`transactionid`), KEY `marketsegment` (`price`,`customerid`), KEY `registersegment` (`cashregisterid`,`price`,`customerid`), KEY `pdc` (`price…of the B+tree, having multiple buffer pool instances to …
Post: MariaDB 5.3 is released as GA!
March 5, 2012 By 17 Comments
… of useless tables in joins Thread pooling and a segmented key cache for improved scalability That’s really just a sampling. A… contention, better diagnostics, improvements to partitioning, and the addition of multiple InnoDB buffer pools. Best of all, MariaDB 5.5 might…
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 2 Comments
… be reading the same page multiple times into the buffer pool. So considering this drawback, Batched Key Access (BKA) optimization was introduced…’ optimizer_switch=’join_cache_incremental=on’ optimizer_switch=’join_cache_hashed=on’ optimizer_switch=’join_cache_bka=on’ join_cache_level=8 join_buffer…
Post: Using Multiple Key Caches for MyISAM Scalability
November 26, 2008 By 8 Comments
… also use multiple Key Caches to reduce or virtually eliminate key cache contention. Too bad you can only map single table to single key cache – it would be so much more helpful if you could use multiple key caches for the same table, for example caching even/odd key…
Post: Crashes while using MyISAM with multiple key caches
July 18, 2009 By Leave a Comment
… related to multiple key caches but to online key cache resize. It is just this code most actively used in case you’re using multiple key caches. It is very rare one would resize single key cache in production and it only triggers… less than 1% of people would resize key cache while server is up or use multiple key caches. The fix of it is not easy…
Post: Getting annoyed with MyISAM multiple key caches.
May 1, 2009 By 11 Comments
As I’ve wrote few times using multiple key caches is a great way to get CPU scalability if you’… problem with multiple key caches and mapping of tables to the different files is – there is no way to see the existing key caches, their… but this is surely sad to see the feature of multiple key caches first introduced in MySQL 4.1 was newer quite polished…
Post: Beware of MyISAM Key Cache mutex contention
August 12, 2008 By 10 Comments
… the same table and so in theory using multiple thread to do inserts in multiple tables would not be bound by table… discussed MyISAM key cache has serious mutex contention issue as there is global mutex which is held for the time of key_block being copied from key_cache to the thread local space. Happily MyISAM allows you to create multiple key caches . We use…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 27 Comments
… key buffer, key_buffer, and key cache interchangeably. However, I will be careful about the difference between “rate” and “ratio”. In this article, the key cache… possibility of having multiple key caches. But I’ll give the simple version here. In my opinion, you should choose a key_buffer_size…
Post: MyISAM Scalability and Innodb, Falcon Benchmarks
October 12, 2007 By 10 Comments
… on Key Read Request. This lock is per key cache so if you have contention while multiple indexes are used you can create multiple key caches and… second confirmation that key_cache is a problem is benchmark run with disabled key_cache (=0). Results for MyISAM with key_buffer_size=0 Threads…
Comment: Using Multiple Key Caches for MyISAM Scalability
April 29, 2010 By 8 Comments
… just wanted to post and confirm that smart use of multiple key caches for MyISAM tables can *dramatically* increase performance in high write… reason (too much history to go into). Before tinkering with multiple key caches I was able to only get 6k – 7k QPS (really… that were candidates for giving their own key cache too. Our approach was not one cache per table but one per group of…
