On 04/17/2002 01:44:46 PM Michael Loftis wrote:
> In many of the cases where it is a primary key it is also there to
> ensure fast lookups when referenced as a foreign key. Or for joins.
Don't know if the optimizer takes this into consideration, but a query that uses a primary and/or unique key in the where-clause, should always choose to use the related indices (assuming the table size is above a certain threshold). Since a primary key/unique index always restricts the resultset to a single row.....
Somebody else mentioned that after creating an index, he still had to run analyze in order to get the optimizer to choose to use the index. I thought that 'create index' also updated pg_stats?
Maarten
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