On 16 Nov 2001, Paolo Cassago wrote:
> I'm testing PostgreSQL, version 7.1.2, and I create a table,
> test1, with these kind of fields:
>
> CREATE TABLE test1 (
> id integer,
> content varchar
> );
>
> with 800.000 records, and a btree index setted on the id field.
>
> I noticed the query uses the index for "=" and "<" operators, but if
> the value used for the "<" operator is higher (600.000 for example),
> the query makes a seq scan of the table, and the index never works
> with the ">" operator. Am I managing the indexes well ?
Let's go through the standard things. :) Have you vacuum analyzed
the table? What does explain show for the queries (particularly the
row count). If the number of rows grabbed is a reasonable percentage
of the table, currently sequence scan *may* be faster than an index
scan, so this may not be incorrect.
