Re: Re: LOL: 122 one column indexes on 122 column table

You have all 122 columns in different combinations searched? Hardly. It is conceivable, but my experience tells me that most of the time it is pure incompetence. I have seen such a situation that you describe with the early "pre-google" web searcher apps. Much more often people don't know that an index can have more than one column. Normally if you want index combine you would go for a bitmap index unless there could be locking issues.

Regards

Lothar

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Von : contact_at_soocs.de
Datum : 19/02/2016 - 12:53 (GMT)
An : laimutis.nedzinskas_at_statoilfuelretail.com, oracle-l_at_freelists.org Betreff : Re: LOL: 122 one column indexes on 122 column table

Hi Laimis,

> That’s…rude.

… or needed by design. Just think about dynamic queries with all possible predicate combinations - impossible to create proper (composite) indexes for all these cases. It may be a valid approach to index each column and let the optimizer work out the combinations (+ "B-tree to Bitmap Conversions"). They also can be used in joins.

Not everything is as crazy as it looks at first view ;-)

Best Regards
Stefan Koehler

Freelance Oracle performance consultant and researcher Homepage: http://www.soocs.de
Twitter: _at_OracleSK  

> Laimutis Nedzinskas <laimutis.nedzinskas_at_statoilfuelretail.com> hat am 19. Februar 2016 um 10:58 geschrieben:
>
> Hi..
>
> I thought I’d seen all.
> Not even close:
>
> 122 column table.
> 122 one-column indexes on EACH column.
> (BLOBs I don’t count, let them be)
>
> That’s…rude.
>
> /Laimis N

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