https://github.com/jamesbriggs/mysql-permute-indexes

Generate all valid indexes for MySQL EXPLAIN to optimize complex queries automatically (SQL index knockout)
https://github.com/jamesbriggs/mysql-permute-indexes

mysql oracle perl postgresql

Last synced: about 1 month ago
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Generate all valid indexes for MySQL EXPLAIN to optimize complex queries automatically (SQL index knockout)

• Host: GitHub
• URL: https://github.com/jamesbriggs/mysql-permute-indexes
• Owner: jamesbriggs
• Created: 2014-11-20T05:44:08.000Z (about 10 years ago)
• Default Branch: master
• Last Pushed: 2014-12-03T05:04:56.000Z (about 10 years ago)
• Last Synced: 2024-07-15T22:11:29.990Z (6 months ago)
• Topics: mysql, oracle, perl, postgresql
• Language: Perl
• Homepage:
• Size: 160 KB
• Stars: 5
• Watchers: 2
• Forks: 2
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
mysql-permute-indexes

=====================

**Summary**

Autogenerate all valid index statements for EXPLAIN to optimize complex queries automatically for MySQL, Postgres, Oracle and SQL Server.

Some use cases:

- accelerate existing Open Source (WordPress, Joomla, etc.) and commercial applications

- test database optimizer results

- stress-test databases with hundreds of index objects

- verify understanding of optimizer index selection  behavior by DBA

- and the most interesting to me, improve performance of infrastructure tools that use metadata stores (OpenStack, CloudStack, DynamoDB, Bacula, etc.) 

Typical performance improvements are 100x to 1,000x for multi-table joins, subselect and reporting queries.

**Example**


$ vi permute_index.pl # (update user settings)


$ permute_index.pl | tee permute_index.txt

   alter table t1 add index idx_jb_001 (c1,c3);

   alter table t1 add index idx_jb_002 (c1,c2,c3);

   alter table t1 add index idx_jb_003 (c1,c3,c2);

   [...]

   alter table t2 add index idx_jb_007 (c4,c5);

   [...]

# load a backup or representative dataset to a dev system (do not run in production!)

$ mysql -h dev -u root -p test <permute_index.txt

$ mysql -h dev -u root -p test

  mysql> explain select * from t1, t2 where c1=c4 and c1=? and c2=? and c3=? and c5=?;

  Table | Key

  ------------------

  t1    | idx_jb_002

  t2    | idx_jb_007

(Now drop all the autogenerated indexes except idx_jb_002 and idx_jb_007.)