…’ve created table with simple structure: mysql> show create table dt2 \G *************************** 1. row *************************** Table: dt2 Create Table: CREATE TABLE `dt2` ( `grp…. Different table structures (ie longer rows) also may affect results, not to mention tables with fragmented rows …
Post: InnoDB: look after fragmentation
November 5, 2009 By 12 Comments
…problem at first. The table is CREATE TABLE `c` ( `tracker_id` int(…+—————————+ 1 row in set (2 min 8.92 sec) mysql> SHOW STATUS LIKE ‘Innodb_scan_pages%’; +——————————+——-+ | Variable_name | …So notes to highlight: InnoDB fragmentation may hurt your query …
Post: Learning about MySQL Table Fragmentation
May 1, 2008 By 19 Comments
… see MySQL becoming CPU bound if IO subsystem is too fast. In this case however I saw neither – The vmstat showed read… SHOW INNODB STATUS output. It was around 20KB which means most reads are single page (16K reads). In case of non fragmented table… fragmentation is also the issue. Interesting enough the “cure” for both fragmentation issues is the same – OPTIMIZE TABLE tbl – this command recreates the table…
Post: MySQL Binaries Percona build10
December 11, 2008 By 12 Comments
… | ON | | slow_query_log_file | /var/lib/mysql/slow_query.log | for compatibility with MySQL 5.1 and | userstat_running | OFF | to… to check fragmentation of the last InnoDB scan | 1.0 | Percona | GPL | The names are Innodb_scan_* | | userstatsv2.patch | SHOW USER/TABLE/INDEX statistics | V2 | Google | GPL | Added INFORMATION_SCHEMA.*_STATISTICS | | show_patches.patch | SHOW PATCHES | 1.0 | Jeremy…
Post: INFORMATION_SCHEMA tables in the InnoDB pluggable storage engine
May 24, 2008 By Leave a Comment
…tables that show some status information about InnoDB. Here are the tables: mysql> SHOW TABLES FROM INFORMATION_SCHEMA LIKE ‘INNODB%’; +—————————————-+ | Tables…
Post: Pretty-formatted index fragmentation with xtrabackup
March 15, 2011 By 4 Comments
…tables and indexes. This can be useful to examine whether you’d benefit from “defragmenting” your MySQL database with OPTIMIZE TABLE… nicely to give an overview of fragmentation. It’s an initial draft, and …generated from the stats output that Vadim showed on an earlier blog post about xtrabackup’…
Post: Long PRIMARY KEY for Innodb tables
October 3, 2006 By 8 Comments
…as with non-clustered tables. The other benefit – it is typical to show multiple thumbnails … worries – checking/repairing large MyISAM tables in case of MySQL/System crash is painful and …table scan for this table would also be slow as it is quite fragmented. Table however is not getting any table…
Post: MySQL File System Fragmentation Benchmarks
March 21, 2008 By 28 Comments
… I found: The fragmentation we speak in this article is filesystem fragmentation or internal table fragmentation which affects performance of full table scan. Not all… tablespace mode showed following results: [root@DB10 ~]# for i in 1 10 100 1000 10000; do ./benchmark.php $i 10000000; mysql -e…
Post: Improved InnoDB fast index creation
November 6, 2011 By 4 Comments
…mysql> SHOW PROFILE; +——————————+————+ | Status | Duration | +——————————+————+ . . . | copy to tmp table | 184.694432 | . . . +——————————+————+ 18 rows in set (0.00 sec) mysql…
Post: Heikki Tuuri answers to Innodb questions, Part II
November 4, 2007 By 13 Comments
… hi amount of concurrent writes to about 6 tables, what version of Innodb/MySQL would you recommend? I’ve been staying at… OPTIMIZE the table, but how long will this take? Is there a facility we can run to show any table / index fragmentation, without having to run the OPTIMIZE? HT: Since OPTIMIZE rebuilds the whole table, it may last…
