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Re: Indexes on array columns

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contrib/intarray might help you

Oleg
On Wed, 15 Mar 2006, karly@xxxxxxxxxxxxx wrote:

On Wed, Mar 15, 2006 at 09:36:04AM -0700, Brendan Duddridge wrote:
Hi,

Is it possible to put an index on an array column?

Apparently yes (I just did it as a test).  However, consider the
following from the manual.

  Tip:  Arrays are not sets; searching for specific array elements
  may be a sign of database misdesign. Consider using a separate
  table with a row for each item that would be an array element. This
  will be easier to search, and is likely to scale up better to large
  numbers of elements.[1]

Arrays are attractive, but it seems they most often aren't the best
solution. FOr instance, I beleive I read somewhere that the index
will be on the whole array, and the individual elements are not
indexed, so

  WHERE ary = {foo,bar}

might benefit from your index, but

  WHERE 'foo' = ANY(ary)

probably wouldn't.  At least that's the impression I got from
reading the archives of this list.  I haven't done any testing of
it.


-karl



1. http://www.postgresql.org/docs/8.0/interactive/arrays.html#AEN5491


Thanks,

____________________________________________________________________
Brendan Duddridge | CTO | 403-277-5591 x24 |  brendan@xxxxxxxxxxxxxx

ClickSpace Interactive Inc.
Suite L100, 239 - 10th Ave. SE
Calgary, AB  T2G 0V9

http://www.clickspace.com




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	Regards,
		Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@xxxxxxxxxx, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83


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