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

  • Thread starter Thread starter Thomas Mercer-Hursh
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Thomas Mercer-Hursh

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The selectivity of *one* index used alone might be bad, but the selectivity of *multiple* of these indices used in combination may be far from bad. That is the point. They are not meant to be used in isolation, but rather to be combined with others. One can, of course, achieve the same functionality and perhaps slightly better performance by defining a multi-field index, but if you need ABC and ACB and ABD and DAB etc. then you have a lot of overhead to cover all needed use cases and have to define a new index if you come up with a new use case. Frankly, when this was introduced, I thought it was brilliant since customers were constantly coming up with new reporting requirements.

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