Re: Dynamic Partitioning using Segment Visibility Maps
От | tomas@tuxteam.de |
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Тема | Re: Dynamic Partitioning using Segment Visibility Maps |
Дата | |
Msg-id | 20080106055736.GB32629@www.trapp.net обсуждение исходный текст |
Ответ на | Re: Dynamic Partitioning using Segment Visibility Maps ("Gokulakannan Somasundaram" <gokul007@gmail.com>) |
Ответы |
Re: Dynamic Partitioning using Segment Visibility Maps
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Список | pgsql-hackers |
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Sun, Jan 06, 2008 at 01:12:32AM +0530, Gokulakannan Somasundaram wrote: > On Jan 5, 2008 6:15 PM, <tomas@tuxteam.de> wrote: > > > > > One thought I had back then, with partitioned tables was "gee -- B-tree > > index is already doing a partition; why do a manual partition on top of > > that?". > Can you please explain more on what you are trying to say here? Sure. A B-tree is just a device to partition something along some order. If you have , say, a table of orders (to use the example upthread) and a B-tree index on order date, this index partitions your set (at recursively finer levels). Of course, you'd have to "sort" your data alogn this index, but PostgreSQL knows how to do this trick: CLUSTER. This was just a vague idea, many things were missing (for example to separate out the more quiescent parts of the table into their own files) which are spelled out in Simon Riggs' proposal. This struck me when seeing people partition tables by hand -- and I was delighted to actually watch Simon forging a real design. Regards - -- tomás -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) iD8DBQFHgG3QBcgs9XrR2kYRAgKhAJ93KUybgMfG07ta67DiR8bgAbHPrgCeOI2V by/xeXKrDJ5O0JZHyFurego= =R/vC -----END PGP SIGNATURE-----
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