| Subject | Re: [firebird-support] Any advantage of a Compound Index across two already indexed fields? |
|---|---|
| Author | Ivan Prenosil |
| Post date | 2006-05-30T08:46:42Z |
> I have a table with two fields that are indexed. One of these fieldsUsual solution would be to create one single field index (FKfield),
> is a foreign key supporting index, the other was defined.
and one compound index (OtherField, FKField).
On large tables with many duplicit values combining two
indexes with bad selectivity can be quite slow and can consume
lot of RAM.
Ivan
http://www.volny.cz/iprenosil/interbase/