ajit_cus wrote: > This is my way of optimizing my count(*) queries under SAPDB: > 1>Select Count(*) from testtable > Takes 1:14 secs returns 240830 > This is the output of explain: > TABLE SCAN > RESULT IS COPIED > > Instead I use this: > 2>Select Count(aNotNullColumnWithanIndex) from testtable > Takes 12 seconds returns 240830 > This is the output of explain: > SINGLE INDEX COLUMN USED (INDEX SCAN) > RESULT IS COPIED > As you can see 2 is lot faster than 1 and should always give > the same result. I only wish that SAPDB was smart enough to > do that internally. >
With version 7.4 your wish became true and if I find some time I'll integrate this feature into version 7.3. > However this can't be the way other DB's function as they are > still a lot faster than the index scan method. Under oracle > any count query (irrespective of index's on columns) seems to > always run in under 1 sec (trying this on an ORACLE table > with 150000 records-->note that it's identical in schema to > my SAPDB test table.) I suppose ORACLE updates a row counter for every insert and delete. But I'm not sure because this could let into concurrency problems. I'm appreciate for every hint on this topic. > I wonder if there are any SAPDB parameters that affect > performance of count queries? no Kind regards, Holger SAP Labs Berlin _______________________________________________ sapdb.general mailing list [EMAIL PROTECTED] http://listserv.sap.com/mailman/listinfo/sapdb.general
