… memory or so on the server too which will make read caching more efficient in its memory while write buffering can… time if Innodb or MyISAM tables are used. There is read-ahead functionality but usually it is not able to drive number… to minimize recovery time significantly by switching to that backup – no data copy will be required which can be significant concern…
Post: The relationship between Innodb Log checkpointing and dirty Buffer pool pages
February 17, 2012 By 10 Comments
This is a time-honored topic, and there’s no shortage of articles on the topic on this blog. I … are flushed down the to the tablespace. If Innodb stops (read: crashes) with dirty buffer pool pages, Innodb recovery must be… dirty page flushing per second (and other background tasks like read-ahead). Make this bigger, you flush more per second. This does…
Post: Recovering Linux software RAID, RAID5 Array
August 27, 2011 By 2 Comments
… however it can scare hell out of you, giving you no access to the data at all. Not all Hardware RAID… Write Access read/write LV Status NOT available LV Size 13.61 TB Current LE 223041 Segments 1 Allocation inherit Read ahead sectors… there are spare sectors available. It might be able to read data from the original sectors or it might fail to…
Post: MySQL 5.5.8 and Percona Server: being adaptive
December 20, 2010 By 25 Comments
… benchmarks above), 4000 and 20000. As you see there is no improvements from bigger innodb_io_capacity, and it also concurs…_method = O_DIRECT innodb_read_ahead = none innodb_flush_neighbor_pages = 0 innodb_write_io_threads=8 innodb_read_io_threads=8 innodb…
Post: Announcing Percona XtraDB Storage Engine: a Drop-in Replacement for Standard InnoDB
December 16, 2008 By 25 Comments
…. Percona XtraDB is released only under the GPL v2 with no dual-licensing, and commercial support is available from Percona. So… IO. Improvements of InnoDB IO subsystem, such as multiple read and write threads, read-ahead control, control io capacity and adaptive checkpointing. documentation…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
… we need to know ahead of time so we don’t spend time on things you have no way to change. An… audit itself is generally a single person, with another person reading all the notes and generally keeping in touch with what… some number of hours, such as 3 hours. Knowing this ahead of time gives us a framework within which we have…
Post: Benchmarking single-row insert performance on Amazon EC2
May 16, 2012 By 17 Comments
… and cons to using secondary indexes. While secondary indexes cause read performance to improve, but they have an impact on the write performance. Well most of the apps rely on read performance and hence having secondary indexes is an obvious choice… concerned with write performance, so I went ahead to choose a table structure with no secondary indexes. Other important things to consider…
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
… to do its work, can you do the work ahead of time so it’s ready to get when … downtime, I would not use MyISAM for anything but read-only tables when things get big. And even … storing all the same data, right? Logically, yes; physically, no. Those values that we pivoted up beside their neighbors …
Post: Recovering Innodb table Corruption
July 4, 2008 By 22 Comments
… the table. In this example I actually went ahead and manually edited test.ibd file replacing few … Running in innodb_force_recovery mode Innodb becomes read only for data operations and so you can’…_recs(page) > 0 || (level == 0 && page_get_page_no(page) == dict_index_get_page(index)) InnoDB: We …
Post: Aligning IO on a hard disk RAID – the Theory
June 9, 2011 By 18 Comments
… it’s guaranteed to be slower both for reading and writing. So, how do we avoid misalignment? …good idea to check that page size is no bigger than stripe element; second – logs are actually… partition table – partition /dev/sdb1 starts 11 sectors ahead of the stripe element start (reminder: 1 sector =…
