Re: Question about cost estimated by Informix engine

Art S. Kagel wrote: > > Leonid Vorontsov wrote: > > > > Hi, All! > > I didn't receive any comments or suggestions about subj NVARCHAR posted > > by me sometime ago. Sorry... But OK, life continues. Next question. > > I have ODS for NT and simple query: > [SNIP] > > Set OPTCOMPIND=0 in your ONCONFIG file and those nasty NESTED LOOP > joins go away in favor of indexes. Make sure you have indexes that > begin with the key join columns on each table and that statistics are > updated according to the suggesions in the release notes. As to the > estimated costs, there is a known problem with those values that is > under investigation, but with OPTCOMPIND=0 you should see more sensible > values anyway. > > Art S. Kagel 1st. OPTCOMPIND parameter is 0 and all indexes is there, I am sure. 2nd. There is line "... You can use MEDIUM or HIGH ..." in release notes. What means word "can"? May be we "must" use ...? There is line "..., try to update statistics..." in the next paragraph. What means word "try"? Does result will be better or not? 3rd. Really I tried use "UPDATE STATISTICS" with various options and in all possible combinations - result was the same. I don't know what can I do and I am waiting You next suggestions. Leonid. ( Leonids.Voroncovs@dati.lv )