I don't know how the primary key checking and the index scan are related in postgresql (but I am keen to learn more about it). >From Sybase ASA (SQL Anywhere) I know, that these two functions (pk checking, index >search) are decoupled. (that means even a primary key without an index is possible. This makes only sense in tables with a few rows).
The pg-planner takes the current number of datasets to calculate a query plan to reach the best performance. If the number of datasets changes (and the user/db-programmer usually knows if it changes) the planner sometimes make wrong decisions. Then I have to execute a "vacuum analyze" or reconnect in case of foreign key checking. I would like to tune postgresql to use an index in any case if it is available. On Fri, 05 Oct 2001 18:01:08 -0400 Tom Lane <[EMAIL PROTECTED]> wrote: > Andreas Wernitznig <[EMAIL PROTECTED]> writes: > > Why don't you skip the automatic index creation for primary keys > > And how then would we enforce uniqueness of the primary key? > > > and let the user decide to create an index, that should be used in any > > case, regardless what the query planner recommends ? > > What? AFAIR the planner does not even *know* whether an index is > associated with a primary key. It certainly does not give such an > index any special preference. > > regards, tom lane > ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org
