… to page flush and i/o problems? Explicit Partition Selection, Split Kernel Mutex, Multi-Threaded Purge, Separate Flush Thread, Pruning the InnoDB Table Cache… for Selects and Updates http://mysqlopt.blogspot.com/2012/06/mysql-how-to-scale-inserts.html [Quote] “However, you can reach better through…
Post: How innodb_open_files affects performance
November 18, 2009 By 4 Comments
…ibd file may be open or closed. Furthermore besides MySQL table_cache Innodb maintains its own (called data dictionary) … dirty pages in innodb buffer pool which had to be flushed before recycling. First ran however was done … files in the list. I guess Heikki knows how to implement LRU in the end …
Post: MySQL Query Cache
July 27, 2006 By 70 Comments
…_blocks relatively to Qcache_free_memory. FLUSH QUERY CACHE command can be used for query cache defragmentation but it may block query cache for rather… idea to use query cache ? Third party application – You can’t change how it works with MySQL to add caching but you can enable query cache so…
Post: How multiple disks can benefit for single client workload ?
April 26, 2008 By 4 Comments
…to see if system is IO bound or CPU bound, while to understand if MySQL goes through more rows than it needs to…to do is to flush transactional log. In case innodb_flush…to wait for it to complete before continuing. Though in decent systems you have battery backed up cache…
Post: How much overhead DRDB could cause ?
June 2, 2008 By 4 Comments
… really need to understand how DRBD works as well as how IO system is utilized to understand how much overhead you… do not realize is MySQL has to deal with multiple logs and perform multiple flushes if operating in maximum…can be getting over 10000 req/sec in-cache write speed (and this is what a lot…
Post: How fast is FLUSH TABLES WITH READ LOCK?
April 24, 2010 By 30 Comments
… started to chat with them about their MySQL backup product. One of the representatives told me that their backup product uses FLUSH TABLES… not attempt to flush its own data to the disk during normal processing. It relies on the operating system to flush the data blocks to disk… dirty blocks in the operating system buffer cache. This can take a long time to flush. During that time, the entire system is…
Post: MySQL should have dynamic durability settings
April 8, 2008 By 4 Comments
…how to commit transaction can be decided for each transaction separately in session context. What MySQL Could do to take it further is to…to flush transaction log some time in the future and COMMIT FORCE to force log flush…
Post: MySQL: Followup on UNION for query optimization, Query profiling
August 14, 2006 By 14 Comments
… show how you can profile queries to see what exactly happens during query execution – very helpful for MySQL Performance optimization: mysql> flush status; Query OK, 0 rows affected (0.00 sec) mysql> SELECT sql_no_cache name FROM…
Post: Beware large Query_Cache sizes
March 23, 2007 By 3 Comments
… couple of months I had number of consulting projects with MySQL Query Cache being source of serious problems. One would see queries… how long FLUSH QUERY CACHE takes – if it is in seconds this is about as long as invalidation can take in extreme case. How to solve the problem ? The easiest solution is to decrease query cache size – smaller values do not…
Post: Battery Learning still problem many years after
February 10, 2011 By 7 Comments
… this for example). You will see for how long battery cache gets disabled in your system (it … to get less penalty going from innodb_flush_log_at_trx_commit=1 and sync_binlog=1 to…MySQL 5.5. Note it might also be good to increase innodb_write_io_threads to get more outstanding requests – without cache…
