… slave is to write all batch jobs to use Gearman MySQL UDF interface to apply update transactions to the master (but… Gearman Worker to take update transactions to apply and pace MySQL transactions to the real master db. You can configure multiple… and allow the client to enable Update Pacing using a MySQL session variable.
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 3 Comments
…server. There is no comparable variables of how many user variables are allocated (and how …sessions have created which temporary tables (both in memory and not): mysql> select * from information_schema.global_temporary_tables \G *************************** 1. row *************************** SESSION…
Post: InnoDB's gap locks
March 27, 2012 By 15 Comments
…. Then, we try to insert another value on the second session: transaction2 > START TRANSACTION; transaction2 > INSERT INTO t VALUES(26); ERROR… options is that the second one is a global variable that affects all sessions and needs a server restart to change its…/doc/refman/5.1/en/innodb-locks-set.html. Conclusion MySQL uses REPEATABLE READ as the default isolation level so it…
Comment: PHP Sessions - Files vs Database Based
April 10, 2012 By 38 Comments
With suggested mysql backed memcached as session handler, there still exists problem with concurrency between simultaneous requests overwriting each others $_SESSION variable. On a multi-frontend environment client’s rapid consecutive ajax requests might end to different frontends accessing and modifying $_SESSION‘s…
Post: MySQL Session variables and Hints
December 28, 2006 By 2 Comments
… in production hints are used much more frequently than setting session variables for given query execution even though it also can be… it is not created dynamically some complex way) – adding extra MySQL calls with possibly their own error control is more complicated…. 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
… as technique to detect the value for DEFAULT variables for SESSION variables, yet for some GLOBAL variables setting them back and forth would not… dealing with MySQL variables in automated way a lot more convenient would be extending INFORMATION_SCHEMA.GLOBAL_VARIABLES Currently as of MySQL 5.5…
Post: Should we give a MySQL Query Cache a second chance ?
April 10, 2011 By 63 Comments
… is appealing to improve performance for MySQL Applications ? Make it Lockless Can we re-implement MySQL Query Cache so it is lockless… 60 stable. We can also get query_cache_ttl as session variable, which is very helpful for connections opened to the slaves… make it cool again. The question is whenever anyone from “MySQL Market Players” – Oracle, MariaDB, Drizzle, Percona Server, will allocate resources…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…MySQL manual, especially the option and variable reference table. But just as frequently, I want to look up blog posts on variables…
Post: What to tune in MySQL Server after installation
September 29, 2006 By 116 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…. I normally leave per session variable tuning to second step after I can analyze workload. P.S Note MySQL distribution contains bunch of…
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… old file based session behavior with MySQL Sessions ? If you have dedicated connection to session database and use Innodb tables for your session storage you…
