On Fri, 2002-11-01 at 08:03, [EMAIL PROTECTED] wrote: > > Hi Rod , > > Does it means that index scan is used for less frequenlty occuring data? > yes my table was not clustered. > > can u tell me what does 0.00..6788.24 and rows and width means? > > in explain out put cost=0.00..6788.24 rows=30001 width=4 > > > I have one more table where i face the similar problem , i have not dump - reloaded > it yet , will post again if i face the problem.
Keep in mind that an index scan is very expensive in regards to a single tuple. It has to run through (fetch) the index pages, then fetch the pages from the table. Since the table fetches are random, the harddrive will probably incur a seek for each tuple found in the index. The seeks add up much quicker than a sequential scan (without nearly as many seeks or drive head movements). -- Rod Taylor ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
