Re: CLUSTER and clustered indices
От | Kevin Grittner |
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Тема | Re: CLUSTER and clustered indices |
Дата | |
Msg-id | 437DC3D60200002500000844@gwmta.wicourts.gov обсуждение исходный текст |
Ответ на | CLUSTER and clustered indices (Simon Riggs <simon@2ndquadrant.com>) |
Список | pgsql-hackers |
That sounds very much like a CLUSTERED INDEX under Sybase ASE (or the derivative Microsoft SQL Server). In those products, when you create a clustered index, the data pages are sorted according to the index sequence, and are used as the leaf pages in the index. A clustered index does not have another leaf level. >>> Simon Riggs <simon@2ndquadrant.com> >>> As an aside, Index Organized Tables (IOTs) isn't just an Oracle term. They first used the term, but the concept had already been implemented in both Tandem (value-ordered) and Teradata (hash-ordered) before this, as well as numerous OLAP systems. The concept doesn't look to be patented. If anybody is looking for a justification for IOTs, the reduction in table volume for large tables is very high. IOTs are the equivalent of removing all of the leaf blocks of the clustered index.
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