[Progress Communities] [Progress OpenEdge ABL] Forum Post: RE: Question about the performance of ABL queries resolved by multiple indexes

[steve pittman]

ABL multi-index query reads only index pages to get its rowid sets for the relevant indexes, and does a very clever intersection of the rowid sets in effect. Note that index pages can be highly compressed, depending on the index key value characteristics (and the rowid values). If I remember correctly, the index read numbers you see are not counting number of index entries accessed in the index pages. This is not a literal description of what happens but is accurate, to the best of my recollection. The description by Thomas Mercer-Hursh is very good. For various reasons, sql does a lot more work for these queries. hope this helps, ....steve pittman

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