Comments on: Clustering indexes vs. Covering indexes http://tokutek.com/2009/05/clustering_indexes_vs_covering_indexes/ Database Performance Sat, 28 Aug 2010 12:16:29 +0000 hourly 1 http://wordpress.org/?v=3.0 By: Xaprb http://tokutek.com/2009/05/clustering_indexes_vs_covering_indexes/comment-page-1/#comment-132 Xaprb Mon, 08 Jun 2009 02:02:38 +0000 http://clustering_indexes_vs_covering_indexes#comment-132 Right. The irritating "key" vs. "index" mis-nomenclature in MySQL strikes again. I understand you now! Right. The irritating “key” vs. “index” mis-nomenclature in MySQL strikes again. I understand you now!

]]> By: Bradley C. Kuszmaul http://tokutek.com/2009/05/clustering_indexes_vs_covering_indexes/comment-page-1/#comment-131 Bradley C. Kuszmaul Mon, 08 Jun 2009 01:57:36 +0000 http://clustering_indexes_vs_covering_indexes#comment-131 I may be misunderstanding your question, but I think the point we were trying to make is that the *key* of a clustering index is typically smaller than the *key* of a covering index. Because in MySQL standard syntax, there is no way to add a column to an index without adding it to the key. Bigger keys can suffer performance problems. (For example, they may reduce the fanout of B-tree-like data structures). The clustering key syntax allows us to store all the extra columns without throwing them into the key. I may be misunderstanding your question, but I think the point we were trying to make is that the *key* of a clustering index is typically smaller than the *key* of a covering index. Because in MySQL standard syntax, there is no way to add a column to an index without adding it to the key. Bigger keys can suffer performance problems. (For example, they may reduce the fanout of B-tree-like data structures).

The clustering key syntax allows us to store all the extra columns without throwing them into the key.

]]> By: Xaprb http://tokutek.com/2009/05/clustering_indexes_vs_covering_indexes/comment-page-1/#comment-130 Xaprb Mon, 08 Jun 2009 01:19:22 +0000 http://clustering_indexes_vs_covering_indexes#comment-130 Why are clustering indexes much smaller than covering indexes? Unless I'm misunderstanding your meaning, this is really not true of InnoDB, for example. Or are you talking about your indexes, and not indexes in general? Why are clustering indexes much smaller than covering indexes? Unless I’m misunderstanding your meaning, this is really not true of InnoDB, for example. Or are you talking about your indexes, and not indexes in general?

]]> By: Bradley C. Kuszmaul http://tokutek.com/2009/05/clustering_indexes_vs_covering_indexes/comment-page-1/#comment-133 Bradley C. Kuszmaul Fri, 29 May 2009 05:12:54 +0000 http://clustering_indexes_vs_covering_indexes#comment-133 Oops, adding z to cvr_idx made the index infeasible (17 columns). I guess that confirms the argument about simplicity... Oops, adding z to cvr_idx made the index infeasible (17 columns). I guess that confirms the argument about simplicity…

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