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

It all nails down to selectivities then. In this particular case..some columns have names CHARSET. No point.

But insert takes 0.5 seconds on a good hardware. That’s...rude.

But yeah, design is consistent. Agree on that

/Laimis N

-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Stefan Koehler Sent: Friday, February 19, 2016 4:29 PM To: l.flatz_at_bluewin.ch
Cc: oracle-l_at_freelists.org
Subject: Re: Re: LOL: 122 one column indexes on 122 column table

Hi Lothar,
the 122 columns are extreme of course, but i just wanted to say that a lot of single column indexes can make sense too. It is not always all for nothing.

> Normally if you want index combine you would go for a bitmap index unless there could be locking issues.

Yes, for sure. However if you look a little bit more closely you also see a mixture of both in SAP BI environments for example (Line-item dimensions vs. High cardinality dimension). Ref: http://scn.sap.com/docs/DOC-46354

Best Regards
Stefan Koehler

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

> "l.flatz_at_bluewin.ch" <l.flatz_at_bluewin.ch> hat am 19. Februar 2016 um 14:32 geschrieben:
>
>
> Hi Stefan,
>
> 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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†Ûiÿü0ÁúÞzX¬¶Ê+ƒün– {ú+iÉ^ Received on Fri Feb 19 2016 - 15:31:44 CET