From: | Victor Yegorov <viy(at)nordlb(dot)lv> |
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To: | Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com> |
Cc: | Rudi Starcevic <rudi(at)oasis(dot)net(dot)au>, Postgres Performance <pgsql-performance(at)postgresql(dot)org> |
Subject: | Re: constraint with reference to the same table |
Date: | 2003-05-15 01:03:41 |
Message-ID: | 20030515010341.GD1549@nordlb.lv |
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Lists: | pgsql-performance |
* Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com> [15.05.2003 03:54]:
>
> That can be a win, but if you're actually dropping and adding the
> constraint again it may not be on large tables since it'll still do a
> whole bunch of index lookups to check the existing rows when the alter
> table add constraint happens. Disabling triggers and re-enabling them is
> faster but breaks the guarantee of the constraint.
You're right. I thought of big tables after posting the reply. My solution
is suitable for my case, i.e. not so big tables.
Returning to the very first question I asked.
May be it is usefull to implicitly create index on foreign key columns?
Actually, untill you had pointed on seq. scans, I thought Postgres is
using internal indicies - don't ask me why.
--
Victor Yegorov
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