Re: SQL Challenge: Arbitrary Cross-tab

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От Greg Sabino Mullane
Тема Re: SQL Challenge: Arbitrary Cross-tab
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Msg-id a1aa78544af9cfda7c505876591e95dc@biglumber.com
обсуждение исходный текст
Ответ на Re: SQL Challenge: Arbitrary Cross-tab  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: SQL Challenge: Arbitrary Cross-tab  (Tom Lane <tgl@sss.pgh.pa.us>)
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> Nope; Gaetano's right, you cannot assume that.  It's entirely possible
> for the planner to choose different plans depending on the OFFSET.
> (Maybe not very likely, with such small offsets, but could happen.)
Interesting. I realized that there was a finite chance of different
plans being chosen, but it seemed neigh-impossible since there is
no WHERE clause and the offsets only vary from 0-7. What sort of
different plans would it choose, out of curiosity?
Seq-scan vs. index-scan? Are there any particular cases where the
same plan is guaranteed to be used?
- --
Greg Sabino Mullane greg@turnstep.com
PGP Key: 0x14964AC8 200408192216
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