With a record size of 1k, I'd guesstimate that going with more scans is going to be better than one big scan. This is because a scan that filters out data still has to read that data from disk, and 1k rows are pretty big.
But nothing will beat hard numbers. Build a test setup and let us know which approach works! -ryan On Wed, Feb 23, 2011 at 2:40 PM, Alex Baranau <[email protected]> wrote: > Hello, > > Would be great if somebody can share thoughts/ideas/some numbers on the > following problem. > > We have a reporting app. To fetch data for some chart/report we currently > use multiple scans, usually 10-50. We fetch about 100 records with each scan > which we use to construct a report. > > I've revised data we store and code logic and see that we could really fetch > same data with single scan by specifying filters to filter out data which > doesn't fit the report params. In this case the scan range will be about > 100-200K records from which after filtering we'd get the same records as we > do currently fetch with multiple scans. > > So the question is: given these numbers (10-50 scans fetching 100 records > each VS 1 scan + filters on range of 100-200K records) will the optimization > I have in mind really improve performance? Unfortunately we don't have good > volume of data currently to perform tests on. May be someone can share > thoughts based solely on these numbers? Record size is about 1Kb. > > Thank you! > Alex Baranau >
