…_join: No Tmp_table: No Tmp_table_on_disk: No # Filesort: No Filesort_on_disk: No Merge_passes: 0 # No InnoDB statistics… queries are being executed. This is where Jeremy’s SHOW PROFILE patch – which is included in all Community tree based Percona… digging deeper. On the other hand, this way of manual profiling you can’t really see real time stats, for example…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
….commanual core_fileblogpercona.commanual Created_tmp_disk_tablesblogpercona.commanual Created_tmp_filesblogpercona.commanual ….commanual print_defaultsblogpercona.commanual profilingblogpercona.commanual profiling_history_sizeblogpercona.commanual protocol_versionblogpercona.commanual …
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
Overview Profiling, analyzing and then fixing queries is likely the most oft-…_join: No Tmp_table: No Tmp_table_on_disk: No # Filesort: No Filesort_on_disk: No Merge_passes: 0 # InnoDB_IO_r… nearly 40 pages from disk. Let’s analyze next part of the output produced by pt-query-digest. # Profile # Rank Query ID…
Post: Improved InnoDB fast index creation
November 6, 2011 By 4 Comments
…Records: 4194304 Duplicates: 0 Warnings: 0 mysql> SHOW PROFILE; +——————————+————+ | Status | Duration | +——————————+————+ . . . | copy to tmp table | 184.694432 | . . …. it does not have to do random disk seeks to fetch secondary index pages to…
Post: Write contentions on the query cache
September 5, 2012 By 5 Comments
… I used commands you’re probably familiar with: EXPLAIN, SHOW PROFILE, SHOW STATUS LIKE ‘Handler%’. EXPLAIN and Handler counters only confirmed… same, I got around 200 lines of output from SHOW PROFILE instead of the 15 lines above. Particularly interesting, a sequence… suspect either some change in data access pattern (reads on disk vs reads in memory, execution plan instability) or contention somewhere…
Post: SystemTap - DTrace for Linux ?
September 14, 2009 By 17 Comments
… able to get profiling of kernel and system calls. Here is simple script to show IO activity per disk per process (well… work in userspace. That is you can use it to profile your and any application that has -debuginfo packages ( all -debuginfo… -g. Well, there seems another war story going on. To profile userspace application with SystemTap your kernel should be patches with…
Post: To find the bottleneck, stop guessing and start measuring
August 4, 2008 By 8 Comments
… at 25% CPU usage and was writing some files to disk, but not waiting on I/O. What’s going on… improve your performance is build profiling into your application, or run the application under a profiler (Google for “profiling
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 28 Comments
… slow and is a problem for my application. I have profiled it with SHOW STATUS and I know it causes a… “mostly factual” above, because Key_reads actually aren’t physical disk reads at all. If the requested block of data isn… randomly positioned, which is a worst-case scenario for spinning disks. This is also very hard to prove, but seems reasonable…
Post: Percona-XtraDB-9.1: released and new coming features
March 17, 2010 By 14 Comments
… for each query: # Bytes_sent: 4973 Tmp_tables: 1 Tmp_disk_tables: 1 Tmp_table_sizes: 7808 That is you can… used, was it disk table or in-memory, and how big was temporary table. Also you can profile each individual query from… replication Show internal InnoDB data dictionary Show InnoDB locking/io profiling in slow.log I hope you enjoy our work!
Post: Using LoadAvg for Performance Optimization
December 4, 2006 By 5 Comments
…” state or in “uninterruptable sleep” state which typically corresponds to disk IO. You can also map LoadAvg to VMSTAT output – it… you can’t use another drive instead), and the fact disks can optimize multiple outstanding requests a bit better compared to… always available unlike other metrics. It is best to have profiling information so you can see as response time for your…
