Thanks for your valuable inputs ! The cost is "13.88" to fetch 1 row by scanning an Primary Key >> indexed column. >> >> Isn't the cost for fetching 1 row is too high ? >> > > Not really. The "cost" is really just an estimate to rank alternate query > plans so the database picks the least expensive plan. The number '13.88' is > basically meaningless. It doesn't translate to any real-world equivalent. > What you actually care about is the execution time. If it takes 0.25ms or > something per row, that's what really matters. > > For what it's worth, it looks like you have the right query plan, there. > Scan the primary key for one row. What's wrong with that? Our systems have > tables far larger than yours, handling 300M queries per day that are far > more expensive than a simple primary key index scan. You'll be fine. :)
Execution time is 0.025 ms per row. I am quite happy with the execution time, even the plan is going the correct way. The total execution time reduced from 2.5 hrs to 5.5 seconds. I am looking for a room for further improvement -- probably quite ambitious :-) .. But, when i reduced random_page_cost to 2, the cost reduced to 7.03 and execution also have reduced by almost 50%. Is this an gain ? Please comment ! Thanks, VB _________________**________________ > > See > http://www.peak6.com/email_**disclaimer/<http://www.peak6.com/email_disclaimer/>for > terms and conditions related to this email >
