… open files that obviously takes time too. I did not double check it using lsof etc but the post http://www…
Post: Innodb Double Write
August 4, 2006 By 23 Comments
… it is recovered from double write buffer. How much does double write buffer affect MySQL Performance ? Even though double write requires each page written twice its overhead is far less than double. Write to double write buffer is sequential so it is pretty cheap…
Post: kernel_mutex problem. Or double throughput with single variable
December 2, 2011 By 17 Comments
….94 61507.08 So playing with this variable we can double throughput to the level with 32-64 threads. I am…
Post: Beware of MyISAM Key Cache mutex contention
August 12, 2008 By 10 Comments
… of context switches to drop almost tenfold and performance almost doubled. Another interesting result was – adding PACK_KEYS=0 to most actively updated tables almost doubled throughput again (and I would expect to see it more than double if all tables would be converted with this option. This…
Post: Estimating Undo Space needed for LVM Snapshot
June 9, 2008 By 5 Comments
… writes, however similar to Innodb DoubleWrite the overhead is not double – the blocks written to the snapshot can be buffered few… second. Now keep in account Innodb double write buffer (so writes to Innodb tablespace are double) and the fact you are probably…
Comment: PHP vs. BIGINT vs. float conversion caveat
January 11, 2008 By 25 Comments
… THIS case. Refer to IEEE 754 section on 64-bit doubles (it’s a bit more trusted source than php.net/float by the way). Doubles have 52 bits allocated for mantissa, which means that 52… be able to manipulate 52-bit integer values stored as doubles without any precision loss. That actually works, and might be…
Comment: InnoDB Flushing: a lot of memory and slow disk
April 1, 2011 By 57 Comments
… good questions like do clean pages need to go to double write buffer ? Probably not, if so how can we write…
Comment: InnoDB Flushing: a lot of memory and slow disk
March 31, 2011 By 57 Comments
… good questions like do clean pages need to go to double write buffer ? Probably not, if so how can we write…
Comment: Fixing column encoding mess in MySQL
January 26, 2011 By 32 Comments
…” glyphs, etc. And some characters look like „« (double-comma, double-left-angle-brackets), or this (in my Navicat view): Ã…
Comment: An argument for not using mysqldump
November 18, 2010 By 24 Comments
… disk subsystem. While I have a snap mounted I’m doubling my write iops. To use the snap as a backup… io subsystem at the same time I’m taking a double-write penalty. We’ve found in our environment that SAN…
