> 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 ?
I don't know, how many index pages will need to be randomly accessed in addition to the random heap access? How many dead versions of the row will need to be visited besides the row which is actually visible? How many of these pages are in shared_buffers? How many of these pages are in OS cache?
Total Index pages are 140310. Yes. I suspect most of the times the required page is found in either OS cache or disk (shared_buffers is .9 GB) as we have 200+ GB of highly active database and the Index is on a 10GB table.
