Re: [U2] Does anyone know the effect of adding an ndex to a UniVerse file?
The date index would contain internal-format dates, and there would be one for every record, as it is the POST.DATE. --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Does anyone know the effect of adding an ndex to a UniVerse file?
I've never heard about MINIMUM.MODULUS, but then again when I did most of my operations & database work late last century, dynamic files did not exist. I've never heard of split operations either. Here are all the ANALYZE.FILE results: >ANALYZE.FILE ABC File name .. ABC ... File type .. DYNAMIC Hashing Algorithm .. GENERAL No. of groups (modulus) 801544 current ( minimum 50021 ) Large record size .. 1619 bytes Group size . 2048 bytes Load factors ... 80% (split), 50% (merge) and 80% (actual) Total size . 2115325952 bytes --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Does anyone know the effect of adding an ndex to a UniVerse file?
That completely depends on how densely the index is populated. Example by extremes: If you index on a status code that has only two equally possible values, you'd have about 5.5 million records in each index. Updates to that file will grind to a near halt. If the code could have a couple of hundred equally different values, update overhead might be acceptable. The same logic applies as to whether or not to use the NO.NULLS option when creating the index. -- Regards, Clif ~~~ W. Clifton Oliver, CCP CLIFTON OLIVER & ASSOCIATES Tel: +1 619 460 5678Web: www.oliver.com ~~~ On Sep 12, 2007, at 11:39 AM, Louie Bergsagel wrote: Does anyone know the effect of adding an index to a UniVerse file? I'd like to add a date index to a type 30 file with 11 million records. ( ANALYZE.FILE Total size . 2,115,325,952 bytes) Would this have any measurable speed slowdown on applications running against the file? The file currently has 4 other indexes. -- Louie Bergsagel Seattle --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
RE: [U2] Does anyone know the effect of adding an ndex to a UniVerse file?
I have seen some slight performance degradation above 4 indices. I usually recommend that you have no more than 6, but 5 or even 6 can be ok, in a pinch. So the answer is that you're approaching the point where there will be a measurable negative impact on throughput. The complete answer is test it & see if the performance hit exceeds your tolerance level. Defining the indices as NO.NULLS helps a lot (I've had folks tell me that they _had_ to index on null values. I'm unconvinced that there's much value in that unless only a tiny percentage of the records will have a null value in the field). With a dynamic file that large, I'd also be looking for ways to minimize split operations. Usually, I'll see a very high percentage of writes doing splits when a dynamic file is that large - and those are expensive writes. You may want to make sure that MINIMUM.MODULUS is not less than CURRENT.MODULUS, and increase it with an ample growth factor. Of course, if you're running in 32 bit mode, you may not have any wiggle room left there, and may want to look into converting this into either 64-bit or a distributed file.> Date: Wed, 12 Sep 2007 11:39:09 -0700> From: [EMAIL PROTECTED]> To: u2-users@listserver.u2ug.org> Subject: [U2] Does anyone know the effect of adding an ndex to a UniVerse file?> > Does anyone know the effect of adding an index to a UniVerse file?> > I'd like to add a date index to a type 30 file with 11 million records. (> ANALYZE.FILE Total size . 2,115,325,952 bytes)> > Would this have any measurable speed slowdown on applications running> against the file?> > The file currently has 4 other indexes.> > -- Louie Bergsagel> Seattle> ---> u2-users mailing list> u2-users@listserver.u2ug.org> To unsubscribe please visit http://listserver.u2ug.org/ _ Can you find the hidden words? Take a break and play Seekadoo! http://club.live.com/seekadoo.aspx?icid=seek_wlmailtextlink --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
