… user is response time, that is how long the user has to wait on results. E…problem with DROP TABLE performance. Does DROP TABLE, running in separate session, affect a response time … target an arrival rate as 3000 transactions per second (regular sysbench transactions). We vary working threads from …
Post: How to debug long-running transactions in MySQL
March 8, 2011 By 6 Comments
…” is a long-running transaction. If a transaction remains open for a very long time without committing, and has modified data, then other transactions could block… what that long-running transaction is doing. Of course, in some cases it’s actually easy to figure out what the long-running transaction is doing…
Post: Innodb undo segment size and transaction isolation
January 12, 2011 By 2 Comments
You might know if you have long running transactions you’re risking having a lot of “garbage” accumulated in … the first data access in transaction, but rather can purge the data after statement is completed. Note long running queries will cause problems…/query is completed. As result if you’re dealing with long running transactions consisting of many queries setting isolation mode to READ-COMMITTED…
Post: Reasons for run-away main Innodb Tablespace
June 10, 2010 By 1 Comment
… of undo space may be required: Running Transaction which does a lot of changes – If transaction modifies a lot of rows it has… tables as it internally commits every 10000 rows. Running Very Long Transaction If you’re running very long transaction, be it even SELECT, Innodb will be unable to purge records for changes which are done after this transaction…
Post: Falcon Storage Engine Design Review
January 12, 2007 By 19 Comments
… very long rollbacks on recovery but also means you should have enough memory to hold all transaction changes. I agree most transactions are small and should be fine but if you have long running transactions, for example batch…
Post: Multiple purge threads in Percona Server 5.1.56 and MySQL 5.6.2
May 3, 2011 By 13 Comments
… the additional purge threads bring. The test workload makes a long history list and then lets purge thread(s) work through… a long-running transaction with a REPEATABLE READ isolation level and started WITH CONSISTENT SNAPSHOT. In the middle of the workload this transaction commits… TPS caused by the number of dedicated purge threads, as long as that number is more than one. Conclusions To conclude…
Post: Beware of running ANALYZE in Production
September 2, 2008 By 10 Comments
… with MyISAM when it scans indexes holding table lock for long period of time. So ANALYZE TABLE should be very fast… mean in practice ? If you have some long running query accessing Innodb table and you run ANALYZE TABLE you will be unable to… completes. For applications which run short transactions it may not be the big deal but if you mix long reporting together with real…
Comment: MySQL Replication vs DRBD Battles
May 1, 2008 By 12 Comments
Don’t allow long running transactions and undo is not a problem. Of course, that is easier said than done. But you don’t want long running transactions. They are an instant source of replication delay and force applications to go back to the primary to get current data or stop using the slave.
Comment: MySQL Replication vs DRBD Battles
May 1, 2008 By 12 Comments
Right. You do not want long running transactions in the perfect world, if you can avoid them it … to restrict number of changes transaction could do – enabling such stuff would allow to catch users running bad transactions easily. Again my point is not to say generally it is good or bad but highlight the problems you can run…
Comment: Falcon Storage Engine Design Review
September 24, 2007 By 19 Comments
…I agree most transactions are small and should be fine but if you have long running transactions, for example batch jobs you may end…, preferred way to use Interbase/Firebird is a bi-transactional mode: one transaction is never-closing read-only read-commited one, another… in a serie of short-lived not-read-only serializable transactions. Guess something alike will work fine for most application over…
