… native support. It would be great if Innodb would implement command to preload table to Innodb buffer pool, which would simply go…=0 This works relatively well (though can be slow for fragmented tables) but it does not preload indexes in memory neither… best preload speed ? It depends – depending on key/clustered key fragmentation it may be faster to run queries one by one…
Post: Pretty-formatted index fragmentation with xtrabackup
March 15, 2011 By 4 Comments
… the Perl script) has support for printing out stats on InnoDB tables and indexes. This can be useful to examine whether… formats the stats output nicely to give an overview of fragmentation. It’s an initial draft, and if you find issues…
Post: Moving from MyISAM to Innodb or XtraDB. Basics
November 22, 2010 By 2 Comments
… in MyISAM but would not fit to Innodb, though this is an exception. Space Innodb Tables tend to be larger. Again converting… usage Innodb tables may increase in size significantly due to fragmentation. Usage Differences What works well for MyISAM may not work for Innodb… most important values to check are innodb_flush_log_at_trx_commit, innodb_buffer_pool_size and innodb_log_file_size. There are…
Post: INFORMATION_SCHEMA tables in the InnoDB pluggable storage engine
May 24, 2008 By Leave a Comment
… FROM INFORMATION_SCHEMA LIKE ‘INNODB%’; +—————————————-+ | Tables_in_INFORMATION_SCHEMA (INNODB%) | +—————————————-+ | INNODB_CMP | | INNODB_CMP_RESET | | INNODB_CMPMEM | | INNODB_CMPMEM_RESET | | INNODB_LOCK_WAITS | | INNODB_LOCKS | | INNODB_TRX | +—————————————-+ The _CMP tables show statistics about compression; they contain a lot of useful information about compression, decompression, memory management, fragmentation…
Post: MySQL Users Conference - Innodb
May 9, 2007 By 6 Comments
… me start with most popular transactional storage engine for MySQL – Innodb. Innodb Storage Engine was covered in a lot of talks, many… compressed to for data and for various indexes. How many “fragmented” pages do we have in the index with current compression… about probably since my first days as Innodb user when I found out ALTERing Innodb tables may take a lot of time…
Post: Long PRIMARY KEY for Innodb tables
October 3, 2006 By 8 Comments
… and spoke a lot about using short PRIMARY KEYs with Innodb tables due to the fact all other key will refer…`,`thumb_width`,`thumb_height`) ) ENGINE=InnoDB; Why did I use this solution compared to others: Innodb Tables – This table is getting much… this table would also be slow as it is quite fragmented. Table however is not getting any table scans just single…
Comment: Working with many files and file system fragmentation
March 22, 2008 By 11 Comments
Some time ago (2006) I noticed that even on a fully defragged NTFS drive newly created InnoDB data files got scattered around the whole partition. http://jroller.com/dschneller/entry/strange_innodb_fragmentation
Comment: Full table scan vs full index scan performance
November 24, 2012 By 15 Comments
Sergei, Indeed Innodb table may be fragmented so full table scan will not be sequential, yet same is true for MyISAM which over time will get fragmented rows. Freshly created Innodb table will most likely result in a lot of sequential reads. Though even in the most fragmented…
Post: How multiple disks can benefit for single client workload ?
April 26, 2008 By 4 Comments
… request can only be issued after previous request is completed. Innodb tries to optimize these reads a bit – there is sequential… which is stored on single disk. Assuming it is not fragmented it will take N tracks on this disk. Now if… it spread across all tracks, if you use 100GB non fragmented block on 1TB hard drive you will have 10 seeks…
Comment: Falcon Storage Engine Design Review
January 12, 2007 By 19 Comments
… would emphasize it in current Limits section though. Isolation Modes: Innodb, Oracle, PostgreSQL also support MVCC but frequently offer it in… not changed by update statement. Thanks for clarification about row fragmentation – so row is not moved to new page if it… not fit to the old one any more but gets fragmented now right ? Regarding real world applications – very significant part of…
