On Wed, Dec 13, 2006 at 02:01:46PM -0800, Ben wrote: > > > On Wed, 13 Dec 2006, Martijn van Oosterhout wrote: > > >>- 7.3 isn't smart enough to use an index on an insert? Seems unlikely. > > > >This question makes no sense, you don't need an index to insert. > > Wouldn't it need to check the unique constraint (an index on the table) > before the insert can succeed? It seems like it would be better to check > the index than to do a full table scan to try to satisfy that constraint.
When you insert a tuple, it needs to be inserted into the index, yes. There is no way an insert can cause a sequential scan, except by some trigger defined on the table. > >Are you sure it's not due to some foreign key check? > > No, but it seems unlikely, given that the vast majority of activity is > inserts into a single table, and that this table has massive amounts of > sequential scans according to pg_stat_user_tables. You're not doing a select within the insert statement are you? Have a nice day, -- Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ > From each according to his ability. To each according to his ability to > litigate.
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