…’t able to get to your question during the initial session, so I’ll address those lingering questions in this post… virtual machines? A: I covered this a bit during the session, but to provide a bit more commentary. There are really…, there are plenty of other MySQL and OS-level status variables that you might want to keep an eye on to…
Post: MySQL Session variables and Hints
December 28, 2006 By 2 Comments
… A FORCE INDEX(A) JOIN B The other part is session variable. If you know query is going to require large sort… in production hints are used much more frequently than setting session variables for given query execution even though it also can be…. The great solution I think would be to allow per session variables to be changed only for single query execution and returned…
Post: Can we improve MySQL variable handling ?
February 18, 2012 By 8 Comments
MySQL Settings (also known as Server Variables) have interesting property. When you set variable in running server this change is not persisted… as technique to detect the value for DEFAULT variables for SESSION variables, yet for some GLOBAL variables setting them back and forth would not…
Post: PHP Sessions - Files vs Database Based
March 27, 2007 By 38 Comments
… same session at the same time. First of course means you may have your session data damaged because you will have lost session variables… file based session behavior with MySQL Sessions ? If you have dedicated connection to session database and use Innodb tables for your session storage you…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
… especially the option and variable reference table. But just…session_cache_missesblogpercona.commanual Ssl_session_cache_modeblogpercona.commanual Ssl_session_cache_overflowsblogpercona.commanual Ssl_session_cache_sizeblogpercona.commanual Ssl_session_cache_timeoutsblogpercona.commanual Ssl_sessions…
Comment: 10+ Ways to Crash or Overload MySQL
November 13, 2007 By 20 Comments
…: Server Side Variables vs Session variables I think by “Server Side Variables” you mean “User-defined variables” like SELECT @myvar:=’myvalue’; and by “Session variables” you mean a user can do SET @@session.some_resource…
Post: Timezone and pt-table-checksum
September 25, 2012 By 1 Comment
…:test-master*/; This is where we can use the @@session.time_zone variable to our advantage. If both servers were set up…`) WHERE (1=1) FOR UPDATE; When you update your session timezone (SET @@session.time_zone = “+01:00″ for example), you will see… a very powerful tool when you need to influence the session variables on different servers for whatever reason.
Post: What to tune in MySQL Server after installation
September 29, 2006 By 118 Comments
… all of these are global variables. These variables depend on hardware and mix of storage engines, while per session variables are typically workload specific…. Furthermore doing so may decrease performance. I normally leave per session variable tuning to second step after I can analyze workload. P…
Comment: PHP Sessions - Files vs Database Based
March 27, 2007 By 38 Comments
… sessions. If you have high concurrency within single session it of course does not work well but in this case plain MySQL sessions based session storage may not work for you either because there will be large chance to loose session variables updates.
Comment: MySQL 5.5 lock_wait_timeout: patience is a virtue, and a locked server
March 1, 2013 By 5 Comments
… lock_wait_timeout. It’s both a global and session variable. If your session doesn’t like the default, it can be changed… my.cnf – it will affect all your sessions. Setting a default value to any variable is always subjective, and the choice of…
