Subject Doubt about indexes
Author Nicolas Rodriguez
Hi all.
I've two tables: A (fields: f1, f2, f3, f4, a1, a2) and B (fields: f1, f2,
f3, f4, b1, b2, b3). Table A has 15000 records and table B 315000 records. I
generally perform joins between this to tables using a.f1=b.f1 and a.f2=b.f2and
a.f3=b.f3 and a.f4 = b.f4. Both tables has an Id field as their primary
keys. Both tables have an index with this four fields. Both tables have
separated indexes like an index in f2 and f3 fields, an index in f4 field,
etc, because the're used in WHEREclauses. Questions:

1) If I have a compound index with this four fields, if I do a select with a
where clause like f1=<some value>, can FB use this index?
2) Could this duplicated indexes hurt database performance?
3) Any pointers on compound indexes' use?


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