Wow, Super detailed explanation. I want to avoid the Katrina effect but 1. I am not sure what to check for, I can run ANALYZE.FILE and get the below results (i his the right way to inspect my "levees" or should I be using something else? I am just used to using jRF -R jASE report only) and HASH.HELP and I am not sure what to use for dynamic files to "inspect" them.
>ANALYZE.FILE PARTS File name .................. PARTS Pathname ................... PARTS File type .................. DYNAMIC Hashing Algorithm .......... GENERAL No. of groups (modulus) .... 240052 current ( minimum 1 ) Large record size .......... 1600 bytes Group size ................. 2048 bytes Load factors ............... 80% (split), 50% (merge) and 35% (actual) Total size ................. 907905024 bytes Thanks for the great explanation Dougc Ps On a semi related subject, I sure do miss fry's, there is not one here in NC ......... -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dan Fitzgerald Sent: Tuesday, July 22, 2008 7:28 PM To: [email protected] Subject: RE: [U2] static/dynamic file(s) opinions wanted! And once a dynamic file starts splitting, writes become very inefficient. I'd say that the most efficient file is a well-sized static one. You want it "wide & shallow". I'm not against having a mod larger than the number of items anymore, especially if the file is going to grow. If I know that the file is going to grow to 1.5Gb, I'll create it that large. With today's storage technologies, having empty groups isn't all that bad a thing. The old "empty groups impact SELECT statements" isn't as true as it once was, and if you do so many selects that it's an issue, you might want to look into indices. I saw a 1Tb drive at Fry's for $170 the other day, so space isn't an issue anymore, either. Dynamic files used to be sold as "you don't have to maintain them". You do, though. If your current mod is GT your minimum mod, you should resize up with a different min mod. That's maintenance. The reason is that your file has reached a point where you're adding data to a file with an increasing chance that the group is already near the split %. When that happens, your write turns into a beast. It has to go to whatever mechanism your OS has for finding free space, attaching that, updating that table, dividing the data in RAM between the two groups (old & new), read in the header (& there's only one per file, no matter how many users want it), lock it, update it with the new structure, write it, unlock it, write out the old group, write out the new group. Undersized static files can be as bad, but dynamic files have the "Katrina effect". Everybody expects that the levees will hold, and FEMA will rescue them, and dynamic files don't need maintenance, so they don't check to be sure... > From: [EMAIL PROTECTED]> To: [email protected]> Subject: RE: [U2] static/dynamic file(s) opinions wanted!> Date: Tue, 22 Jul 2008 18:25:50 -0400> > Thanks Kevin but I am still missing something, if dynamic files are well> "dynamic" why would one need to resize them and how would one know what to> resize them to? I am sorry if this is basic stuff but I come from a jBASE> world and have never really used dynamic files. > > you cannot run HASH.HELP on a dynamic file and ANALYZE.FILE does not seem to> return anything useful in resizing, so how would one determaine (without> using a rool like the ones previously mentioned). I LOVE to use tools like> these BUT I also like to know how to do it manually in case I cannot use> these tool(s) (for whatever reason).> > I guess the gist of my question(s) would be > > 1. how to tell if a dynamic file needs to be resized> 2. my other question about which is better seems to be that dynamic files> are if you have LOTS of files and they grow a lot and you cannot maintain> them> > thanks everyone!> > dougc> > > -----Original Message-----> From: [EMAIL PROTECTED]> [mailto:[EMAIL PROTECTED] On Behalf Of Kevin King> Sent: Tuesday, July 22, 2008 4:36 PM> To: [email protected]> Subject: Re: [U2] static/dynamic file(s) opinions wanted!> > Files that grow at a controlled rate and especially files that could exceed> 2G are good candidates for dynamic files. Files that are cleared, or files> that have masses of data loaded or removed from them, are not. Work files,> for example, can be a horrible use of dynamic files. As was stated earlier,> it's crucial that the original block size of the dynamic file be set> properly, otherwise the file could split way too often.> > On Tue, Jul 22, 2008 at 1:02 PM, Symeon Breen <[EMAIL PROTECTED]> wrote:> > > We use dynamic files no problem - yes I suppose in certain circumstances> > there is an overhead, but it would still be faster than a badly sized> > static> > file. The conclusion we have is if you are really on top of your file> sizes> > and administrating things daily there is probably less need for dynamic> > files. If however you have hundreds of accounts and files then dynamic> > files> > are easier to admin and hence probably faster in the long term.> >> >> >> > Symeon.> >> >> >> > -----Original Message-----> > From: [EMAIL PROTECTED]> > [mailto:[EMAIL PROTECTED] On Behalf Of doug chanco> > Sent: 22 July 2008 16:36> > To: [email protected]> > Subject: [U2] static/dynamic file(s) opinions wanted!> >> > hey all,> > I have "heard" bad things about using dynamic files versus> > hashed/static ones. Can anyone share any thoughts on which is better> > (in particular on a system where the files grow at a fairly steady rate).> >> > I always understood that dynamic files were best on files that did not> > change "that much that fast " as the constant need to resize would> > outweigh the manual effort of resizing the files manually (or with a> > program).> >> > I am looking for insight (or where to find some insight) on universe and> > best file practices (right now I am reading the system description> > manual and its helping but lacks insights that I am sure some of the old> > pickies on here have)> >> > so any thoughts/suggestions/ideas/comments are welcomed!> >> > thanks> >> > dougc> >> > ps> >> > universe 10.1 and aix 5.2> > -------> > u2-users mailing list> > [email protected]> > To unsubscribe please visit http://listserver.u2ug.org/> > No virus found in this incoming message.> > Checked by AVG - http://www.avg.com> > Version: 8.0.138 / Virus Database: 270.5.3/1565 - Release Date: 7/21/2008> > 6:36 PM> > -------> > u2-users mailing list> > [email protected]> > To unsubscribe please visit http://listserver.u2ug.org/> >> > > > -- > -Kevin> http://www.PrecisOnline.com> -------> u2-users mailing list> [email protected]> To unsubscribe please visit http://listserver.u2ug.org/> > > __________ Information from ESET NOD32 Antivirus, version of virus signature> database 3289 (20080722) __________> > The message was checked by ESET NOD32 Antivirus.> > http://www.eset.com> > > > __________ Information from ESET NOD32 Antivirus, version of virus signature> database 3289 (20080722) __________> > The message was checked by ESET NOD32 Antivirus.> > http://www.eset.com> -------> u2-users mailing list> [email protected]> To unsubscribe please visit http://listserver.u2ug.org/ _________________________________________________________________ Use video conversation to talk face-to-face with Windows Live Messenger. http://www.windowslive.com/messenger/connect_your_way.html?ocid=TXT_TAGL M_WL_ Refresh_messenger_video_072008 ------- u2-users mailing list [email protected] To unsubscribe please visit http://listserver.u2ug.org/ -- This message has been scanned for viruses and dangerous content by SecureMail, and is believed to be clean. ------- u2-users mailing list [email protected] To unsubscribe please visit http://listserver.u2ug.org/
