… mysqldump, the query that scans data by primary key was slow. How slow ? Let me show. The query in question is (Q1…: 11569733 # InnoDB_IO_r_ops: 38530 InnoDB_IO_r_bytes: 631275520 InnoDB_IO_r_wait: 0.204893 # InnoDB_rec_lock_wait: 0.000000 InnoDB_queue_wait: 0.000000 # InnoDB_pages…
Post: A (prototype) lower impact slow query log
September 20, 2012 By 12 Comments
… something else.. say an innodb data file, and writing part of your slow query log as an innodb page will not end in… can be found at lp:~stewart/percona-server/5.6-slow-query-plugin-prototype (this revision) – this will probably build fine… out at the following: straight MySQL (no slow query log): 13 seconds MySQL with slow query log enabled: 18 seconds My audit…
Post: Solving INFORMATION_SCHEMA slowness
December 23, 2011 By 25 Comments
… for example how much space innodb tables are using and things like it. Besides being just slow accessing information_schema can often… which is very fast for Innodb but by the fact MySQL by default looks to refresh Innodb statistics each time table is… it anyway. This will not make Innodb to operate without statistics at all as Innodb will still compute statistics for the table…
Post: Optimizing slow web pages with mk-query-digest
April 7, 2011 By 14 Comments
…_query_time=0 and all the eXtra benefits from Percona slow query log patch), I knew some particular pages were taking… 2.71k 199.17 363.48 206.60 151.03 # InnoDB: # IO r bytes 0 0 0 0 0 0 0… 0% yes, 99% no # String: # Databases prod_db # Hosts localhost # InnoDB trxID 1153145C (2/0%), 11531626 (2/0%)… 43 more # Last…
Post: My "hot" list for next InnoDB features
March 30, 2009 By 18 Comments
Many InnoDB scalability problems seem fixed in InnoDB-plugin-1.0.3 and I expect InnoDB-plugin will run fine on 16-24… especially bad at start time, when InnoDB takes probes during opening table, as it is slow operation. See also http://www.mysqlperformanceblog… asked what are our current plans about XtraDB with recent InnoDB-pluging release, as performance improvements in plugin may make XtraDB…
Post: How to load large files safely into InnoDB with LOAD DATA INFILE
July 3, 2008 By 29 Comments
… purge thread cannot purge them, so everything gets bloated and slow. Even simple SELECT queries might have to scan through lots… machine from another, which takes about 10 or 12 hours. InnoDB is not optimized for rollbacks, it’s optimized for transactions…, col2 bigint(20) default NULL, key(col1), key(col2) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 Here’s the result of loading the…
Post: COUNT(*) for Innodb Tables
December 1, 2006 By 32 Comments
… guess note number one about MyISAM to Innodb migration is warning what Innodb is very slow in COUNT(*) queries. The part which I…. This can be faster or slower both for MyISAM and Innodb depending on various conditions. In real applications there are much…” but these are normally easy to remove. So remember Innodb is not slow for ALL COUNT(*) queries but only for very specific…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 141 Comments
… index ranges are scanned. There are also clustered keys in Innodb which combine index access with data access, saving you IO… star join with dimention tables being small it would not slow things down too much. On other hand join of few large tables, which is completely disk bound can be very slow. One of the reasons elevating this problem in MySQL is…
Post: How innodb_open_files affects performance
November 18, 2009 By 4 Comments
… InnoDB: Starting crash recovery. InnoDB: Reading tablespace information from the .ibd files… InnoDB: Restoring possible half-written data pages from the doublewrite InnoDB: buffer… InnoDB…you like – there is no any surprises such as surprised slow downs for replacing open files in the list. I …
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 19 Comments
… may not see a “free space” in Innodb tablespace to grow significantly. Q6: Does Innodb policy replacement algorithm takes into account page… MySQL 5.1 Q15: How frequently does Innodb fuzzy checkpointing is activated HT: InnoDB flushes about 128 dirty pages per flush. That… which slows down throughput. If we could control the checkpointing rate we could use an 8G write ahead log and tell innodb…
