Oracle Performance Tuning

[ammachiyar_mtech]

In a select query if we have many and conditions how the query will executed. Which condition will be executed first (left to right, from right to left, based on any other execution criteria)?. if we have and conditions for both number and varchar field which field will be queryed first. How the execution takes place internally?.

Whether Arranging the fields in (and) condition will improve the performance of the querying a table containing 26 lakhs record, that returns only 2000 records.


Ammachiyar C

[ammachiyar_mtech]

we have two fields namely port_id(varchar2(10)) and subscriber(varchar2(25)) for both fields we have seperate nonunique indexes for both the fields.but on querying one port_id it takes fraction of minutes but with the field subscriber it takes 5 minutes to query the output.

Both the column contains 26 lakhs records.

I would like to know the performance of this query based on timings.