…Interview for people to work as MySQL DBAs or be involved with MySQL Performance in some way is…or many tables increase it larger. I’ve seen values over 100.000 used. thread_cache Thread creation… if it is well used. For certain workloads cache hit ratio is lower than would justify having it enabled. …
Post: Predicting Performance improvements from memory increase
August 7, 2008 By 6 Comments
… enough because of MySQL scaling issues it is also possible to see performance to go down as you increase buffer pool size… question – how do we predict the benefit from increasing the memory and so cache sizes ? I typically start by looking at the… estimations and take IO subsystem into account – even with same cache hit ratio more data and more load means there are higher demands…
Post: MySQL Query Cache
July 27, 2006 By 69 Comments
…increases. Demand operating mode If you just enable qury cache it will operate in “Cache everything” mode. In certain caches you might want to cache…hit ratio for certain application. It is not that fast Query Cache…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
… InnoDB 442 mysql tables in use 1, locked 0 MySQL thread id…in undo space. It is increased as transactions which have … are done to OS cache, and being sequential writes …hit ratio which measures buffer pool efficiency. 1000/1000 corresponds to 100% hit rate. It is hard to tell what buffer pool hit…
Post: Cache Miss Storm
September 10, 2010 By 29 Comments
… has a lot of hits in the cache you can get into … is ran all by itself increasing the time it takes server to… the query which has too high ratio of requests to be served with…cache to reflect it is being updated right now so you’re better wait rather than starting populating it. For MySQL Query Cache…
Post: On Good Instrumentation
May 31, 2010 By 1 Comment
…ratio. Checking what is going on with memcache01 shows it just was restarted (and hence has almost empty cache). This is important example as it shows your increased response time from MySQL may not have anything to do with MySQL…
Comment: Evaluating IO subsystem performance for MySQL Needs
March 6, 2008 By 23 Comments
…lookups) per second across a few mysql servers, with 70% read / 30% write ratio – without using O_DIRECT (can’… in WIO. Recently the cache was turned off and there was a hit on performance but that was related to flushing of IOPS so the WIO went up increasing load …
