Comments on: Duplicate indexes and redundant indexes http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/ Everything about MySQL Performance Tue, 02 Dec 2008 14:37:24 +0000 http://wordpress.org/?v=2.5.1 By: Finding out largest tables on MySQL Server « Purab’s Blog http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-344251 Finding out largest tables on MySQL Server « Purab’s Blog Wed, 13 Aug 2008 07:25:01 +0000 http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-344251 [...] to data size often indicates there is a lot of indexes (so it is well possible there are some duplicates, redundant or simply unused indexes among them) or may be there is long primary key with Innodb tables. Of [...] [...] to data size often indicates there is a lot of indexes (so it is well possible there are some duplicates, redundant or simply unused indexes among them) or may be there is long primary key with Innodb tables. Of [...]

]]> By: How to find duplicate and redundant indexes in MySQL at Xaprb http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-338520 How to find duplicate and redundant indexes in MySQL at Xaprb Fri, 01 Aug 2008 12:39:07 +0000 http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-338520 [...] Zaitsev over at the excellent MySQL Performance Blog recently wrote an article on duplicated and redundant indexes — any indexes which cover exactly the same columns as another index, or cover a leftmost [...] [...] Zaitsev over at the excellent MySQL Performance Blog recently wrote an article on duplicated and redundant indexes — any indexes which cover exactly the same columns as another index, or cover a leftmost [...]

]]> By: peter http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-260643 peter Mon, 31 Mar 2008 18:49:14 +0000 http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-260643 Vaibogam, This will catch indexes (A,B) and (A,C) as duplicate would not it ? It would be simple if indexes would be single column only :) Vaibogam,

This will catch indexes (A,B) and (A,C) as duplicate would not it ?
It would be simple if indexes would be single column only :)

]]> By: Vaibogam S http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-260480 Vaibogam S Mon, 31 Mar 2008 15:40:18 +0000 http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-260480 A simple way to find out duplicate indexes in 5.0.x SELECT * FROM information_schema.statistics WHERE table_schema = ‘?’ GROUP BY table_schema, table_name, column_name HAVING count(column_name) > 1; It would be better to include 'index_type' in GROUP BY clause to more accurate answer. In the above query bind the ‘database name’ parameter. -Bog A simple way to find out duplicate indexes in 5.0.x

SELECT * FROM information_schema.statistics WHERE table_schema = ‘?’ GROUP BY table_schema, table_name, column_name HAVING count(column_name) > 1;

It would be better to include ‘index_type’ in GROUP BY clause to more accurate answer.

In the above query bind the ‘database name’ parameter.

-Bog

]]> By: Hitta indexdubletter http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-242037 Hitta indexdubletter Wed, 13 Feb 2008 07:45:07 +0000 http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-242037 [...] läste en artikel på mysqlpeformanceblog om redundanta index. Eftersom jag inte vill skriva om den artikeln så hoppar jag direkt till [...] [...] läste en artikel på mysqlpeformanceblog om redundanta index. Eftersom jag inte vill skriva om den artikeln så hoppar jag direkt till [...]

]]> By: Finding out largest tables on MySQL Server | MySQL Performance Blog http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-238934 Finding out largest tables on MySQL Server | MySQL Performance Blog Mon, 04 Feb 2008 14:46:23 +0000 http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-238934 [...] to data size often indicates there is a lot of indexes (so it is well possible there are some duplicates, redundant or simply unused indexes among them) or may be there is long primary key with Innodb tables. Of [...] [...] to data size often indicates there is a lot of indexes (so it is well possible there are some duplicates, redundant or simply unused indexes among them) or may be there is long primary key with Innodb tables. Of [...]

]]> By: MySQL Performance Blog » Redundant index is not always bad http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-160073 MySQL Performance Blog » Redundant index is not always bad Tue, 28 Aug 2007 09:54:13 +0000 http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-160073 [...] year ago Peter wrote about redundant indexes and mentioned sometimes it is good to leave two indexes, even one is first part of another. I'm [...] [...] year ago Peter wrote about redundant indexes and mentioned sometimes it is good to leave two indexes, even one is first part of another. I’m [...]

]]> By: peter http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-44337 peter Mon, 05 Feb 2007 21:49:31 +0000 http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-44337 Olivier. This is pretty strange idea. Innodb PK is usually most efficient key to use for row data retrieval. Olivier.

This is pretty strange idea. Innodb PK is usually most efficient key to use for row data retrieval.

]]> By: Olivier http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-41839 Olivier Fri, 02 Feb 2007 16:50:14 +0000 http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-41839 Hi, And what about Innodb PK ? I heard that to speed UP queries, I should declare an additionnal key on the PK, and force the use of this key instead of the primary (because innodb PK are stored in fragments). So, true or false ? Hi,

And what about Innodb PK ? I heard that to speed UP queries, I should declare an additionnal key on the PK, and force the use of this key instead of the primary (because innodb PK are stored in fragments). So, true or false ?

]]> By: MySQL Performance Blog » Getting MySQL to use full key length http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-40575 MySQL Performance Blog » Getting MySQL to use full key length Wed, 31 Jan 2007 19:44:45 +0000 http://www.mysqlperformanceblog.com/2006/08/17/duplicate-indexes-and-redundant-indexes/#comment-40575 [...] There is one bug, or "missing feature" in MySQL Optimizer which may give you hard time causing performance problems which may be hard to track down, it is using only part of the index when full index can be used or using shorter index while there is longer index available. The last item is yet another good reason for removing redundant indexes [...] [...] There is one bug, or “missing feature” in MySQL Optimizer which may give you hard time causing performance problems which may be hard to track down, it is using only part of the index when full index can be used or using shorter index while there is longer index available. The last item is yet another good reason for removing redundant indexes [...]

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