Re: [HACKERS] Index creation takes for ever
От | Bruce Momjian |
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Тема | Re: [HACKERS] Index creation takes for ever |
Дата | |
Msg-id | 200403170123.i2H1N9H10786@candle.pha.pa.us обсуждение исходный текст |
Ответ на | Re: [HACKERS] Index creation takes for ever (Manfred Koizar <mkoi-pg@aon.at>) |
Ответы |
Re: [HACKERS] Index creation takes for ever
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Список | pgsql-patches |
Where are we on this? It seems like a win to me. --------------------------------------------------------------------------- Manfred Koizar wrote: > On Mon, 01 Dec 2003 13:32:10 -0500, Tom Lane <tgl@sss.pgh.pa.us> wrote: > >Manfred Koizar <mkoi-pg@aon.at> writes: > >> comparetup_index() compares two IndexTuples. The structure > >> IndexTupleData consists basically of not much more than an ItemPointer, > >> and the patch is not much more than adding a comparison of two > >> ItemPointers. So how does the patch introduce a new low level > >> implementation dependency? > > > >Because it sorts on tuple position, which is certainly about as low > >level as you can get. > > The patch affects only the sort during index creation. Mapping key > values to tuple positions is the sole purpose of an index. The notion > that an index should not care for tuple positions looks a bit strange to > me. > > > More to the point, though, no evidence has been > >provided that this is a good idea. > > The test script I posted with the patch shows that the patch produces > more efficient b-tree indices when there are lots of duplicates. > > Servus > Manfred > > ---------------------------(end of broadcast)--------------------------- > TIP 4: Don't 'kill -9' the postmaster > -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073
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