Good to see a healthy thread spread across a good number of years. Thanks Baron! As I was reading the part… the actual imported data. If the INFILE data file is missing from the slave boxes, then the LOAD DATA command will…
Comment: How to load large files safely into InnoDB with LOAD DATA INFILE
May 9, 2012 By 28 Comments
Post: Percona Live MySQL Conference & Expo Was A Great Event
April 17, 2012 By 2 Comments
… year. In a nutshell, if you weren’t there, you missed a great week, and I hope you’ll join us… exhibitor agreed that their target audience was there in large numbers and actively engaged. The exhibitors deserve a lot of credit…
Comment: Should you move from MyISAM to Innodb ?
March 10, 2012 By 53 Comments
… brings a lot of cons to the table which are missing in MyISAM and vice-versa. MyISAM is like a dog… – you should not use MyISAM. If you have a huge number of concurrent writes and selects and query performance must be…
Post: What MySQL buffer cache hit rate should you target
June 29, 2006 By 5 Comments
… you have 100 rows per page you will get 1 miss per page and 99 hits, making your hit ratio 99… be to look at response time contribution – how much buffer misses (physical reads) contributed to response time ? This would take into… the number of misses – number of IOs which MySQL needs to do. You better to look at global and local (per thread) numbers and…
Post: Cache Miss Storm
September 10, 2010 By 29 Comments
… query with same constants. What we observed was a cache miss storm – situation which can happen with memcache (as in this… you who decide how to populate the cache. There is number of techniques you can use to avoid this problem such… it every 10 minutes and so you get basically no misses. This works best when there are few hot cache entries…
Post: Missing Data - rows used to generate result set
July 20, 2008 By 15 Comments
As Baron writes it is not the number of rows returned by the query but number of rows accessed by the query… log record) is the number of rows which MySQL used to generate result set. Comparing this number with number of rows query actually… always possible to optimize queries so the number of rows accessed is same as number of rows used to generate result set…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 27 Comments
… miss rate is defined as the number of misses per unit of time, with the units of operations per second. The key cache miss… tuned is because, even if you know the absolute numbers, you are missing the element of time, in two important ways. First…: Key_cache_miss_rate = Key_reads / Uptime Note the conspicuous absence of Key_read_requests in the formula. The number of requests…
Post: On Good Instrumentation
May 31, 2010 By 1 Comment
… process transactions and you want it to successfully complete large number of transactions it gets (this is what called availability) and…. There could be many variables in environment which change – load, number of concurrent users, database, the way users use the system… I can see high number of misses. Looking at some available traces shows the server memcache01 has very high miss ratio. Checking what…
Post: MySQL caching methods and tips
April 4, 2011 By 4 Comments
… cloud, this can be very beneficial as may reduce the number of instances you need. Don’t make too many round… portions of pages is a good way to reduce the number of round trips to the cache. Summary tables Queries that… must be rebuilt from scratch each time (like a memcache miss) or they must be updated. Updating the summary tables efficiently…
Post: table_cache negative scalability
November 16, 2009 By 23 Comments
… less. With significantly larger table_cache=16384 (and appropriately adjusted number of open files) the same operation takes 660 seconds which… the table_cache algorithms do not scale well. The absolute numbers are also very interesting – 151 tables/sec is not that… an absolute number. So if you tune table cache is “normal” case and is able to bring down your miss rate (opened…
