RE: [U2] Dymanic vs Dimenssioned
Two wonderful new data types. Dymanic arrays presumably store data that are changing extremely rapidly. I guess Dimenssioned arrays store Scandinavian data. =8^D --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Dymanic vs Dimenssioned
Dude, you've been working with NLS too much. ;-) -- Regards, Clif On May 14, 2005, at 4:51 PM, Ray Wurlod wrote: Two wonderful new data types. Dymanic arrays presumably store data that are changing extremely rapidly. I guess Dimenssioned arrays store Scandinavian data. =8^D --- 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] Dymanic vs Dimenssioned
I am by far from a 'smart person'. But when I was first learning I was told if you were only going to use values in the first few a/m or if was simply a short item, less than 10 or so a/m then you can use dynamic. Anything more than that use dimensioned. If you are going to use say a/m 50 and you use a dynamic array, every time it actually has to start at 1 and work through to find 50. Were if you use a dimensioned array it will go straight to (50). I was shown a nifty table when learning this where it showed all the values the program uses being put into buckets. If you use a dynamic read, it all goes into one bucket. If you use Dimensioned it each goes into it's own bucket. This is my 'simple' minded understanding. I am sure many more answers will be posted on this topic. Thanks, Marilyn A. Hilb Value Part, Inc Direct: 847-918-6099 Fax: 847-367-1892 [EMAIL PROTECTED] www.valuepart.com -Original Message- From: Stevenson, Charles [mailto:[EMAIL PROTECTED] Sent: Friday, May 13, 2005 2:50 PM To: u2-users@listserver.u2ug.org Subject:RE: [U2] I'm in an Array quandry, any suggestions... Maybe the Smart People on this list can give a good rule of thumb for deciding when to READU/WRITE vs. MATREADU/MATWRITE. After all these years, I still don't have one. From: Richard Taylor We are faced with this same situation and the thought behind this truly baffles me. I will admit to some of the same bafflement. Why take a flexible, dynamic database system The syntax for dynamic arrays is more natural for the language, too (e.g., XYZ(17)1,5 vs. XYZ17,5). Readability makes for maintainability, generally the most important contributor to software quality. and force it to be fixed length. well, sorta. Each element of the dimensioned array is a variable length dynamic array. ( See my previous post for how to complicate your life by inserting attribute marks. ) This is what you are doing using dimensioned arrays and MATREADs. The most common justification I have heard is performance and this simply does not hold water. Within limits (but I don't know the limits). If you have a program that manipulates many attributes many times, then it makes sense to matread them into a dimensioned array up front, and matwrite them in the end, thereby limiting big string manipulations. People forget or newbies don't know that CUST.REC117 is really EXTRACT( CUST.REC, 117,0,0) or REPLACE(...,CUST.REC,117,0,0). That can be very expensive when you do that for many attributes many times, with large dynamic arrays. By contrast, each dimensioned array element has its own memory address, so references and assignments can jump straight to it. But I do not have a good appreciation for what limits, many, big really mean in my previous paragraph. Does anyone have a good heuristic? I started in Pick in R83 and have never used a dimensioned array to hold record structure and I have not seen performance issues. This to the extent that we ran an MRP run on a 286 Wyse PC that choked the mainframe at this company. Ah-ha, my dear Watson, then you don't really know how that system would have screamed if you'd used dimensioned arrays instead, do you? The more they complicate the plumbing the easier it is to stop up the drain Yeah. What I said about dynamic array syntax being more natural. cds P.S. Why are we limited to 1- or 2-dimensioned arrays? E.g., DIM XYZ( 5,10,2,3,8 ) would be a 5-dimensional array. --- 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] Dymanic vs Dimenssioned
Do we have archives somewhere? IIRC correctly, Glenn Herbert posted a great description of dynamic array optimization some time ago. I believe the upshot was, bowing to Yogi Berra on his 80th, that the difference ain't what it used to be. Our greatest duty in this life is to help others. And please, if you can't help them, could you at least not hurt them? - H.H. the Dalai Lama When buying selling are controlled by legislation, the first thing to be bought sold are the legislators - P.J. O'Rourke Dan Fitzgerald From: Marilyn Hilb [EMAIL PROTECTED] Reply-To: u2-users@listserver.u2ug.org To: u2-users@listserver.u2ug.org Subject: RE: [U2] Dymanic vs Dimenssioned Date: Fri, 13 May 2005 15:40:17 -0500 I am by far from a 'smart person'. But when I was first learning I was told if you were only going to use values in the first few a/m or if was simply a short item, less than 10 or so a/m then you can use dynamic. Anything more than that use dimensioned. If you are going to use say a/m 50 and you use a dynamic array, every time it actually has to start at 1 and work through to find 50. Were if you use a dimensioned array it will go straight to (50). I was shown a nifty table when learning this where it showed all the values the program uses being put into buckets. If you use a dynamic read, it all goes into one bucket. If you use Dimensioned it each goes into it's own bucket. This is my 'simple' minded understanding. I am sure many more answers will be posted on this topic. Thanks, Marilyn A. Hilb Value Part, Inc Direct: 847-918-6099 Fax: 847-367-1892 [EMAIL PROTECTED] www.valuepart.com -Original Message- From: Stevenson, Charles [mailto:[EMAIL PROTECTED] Sent: Friday, May 13, 2005 2:50 PM To: u2-users@listserver.u2ug.org Subject:RE: [U2] I'm in an Array quandry, any suggestions... Maybe the Smart People on this list can give a good rule of thumb for deciding when to READU/WRITE vs. MATREADU/MATWRITE. After all these years, I still don't have one. From: Richard Taylor We are faced with this same situation and the thought behind this truly baffles me. I will admit to some of the same bafflement. Why take a flexible, dynamic database system The syntax for dynamic arrays is more natural for the language, too (e.g., XYZ(17)1,5 vs. XYZ17,5). Readability makes for maintainability, generally the most important contributor to software quality. and force it to be fixed length. well, sorta. Each element of the dimensioned array is a variable length dynamic array. ( See my previous post for how to complicate your life by inserting attribute marks. ) This is what you are doing using dimensioned arrays and MATREADs. The most common justification I have heard is performance and this simply does not hold water. Within limits (but I don't know the limits). If you have a program that manipulates many attributes many times, then it makes sense to matread them into a dimensioned array up front, and matwrite them in the end, thereby limiting big string manipulations. People forget or newbies don't know that CUST.REC117 is really EXTRACT( CUST.REC, 117,0,0) or REPLACE(...,CUST.REC,117,0,0). That can be very expensive when you do that for many attributes many times, with large dynamic arrays. By contrast, each dimensioned array element has its own memory address, so references and assignments can jump straight to it. But I do not have a good appreciation for what limits, many, big really mean in my previous paragraph. Does anyone have a good heuristic? I started in Pick in R83 and have never used a dimensioned array to hold record structure and I have not seen performance issues. This to the extent that we ran an MRP run on a 286 Wyse PC that choked the mainframe at this company. Ah-ha, my dear Watson, then you don't really know how that system would have screamed if you'd used dimensioned arrays instead, do you? The more they complicate the plumbing the easier it is to stop up the drain Yeah. What I said about dynamic array syntax being more natural. cds P.S. Why are we limited to 1- or 2-dimensioned arrays? E.g., DIM XYZ( 5,10,2,3,8 ) would be a 5-dimensional array. --- 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/ --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
RE: [U2] Dymanic vs Dimenssioned
I was also taught the same thing, back in the day. But, I think nowadays, what with the faster processor and disk speeds, it doesn't really matter that much anymore. About 15 years ago, working on a Sequoia, it was proven that by using dimensioned arrays for reads and writes in a OLTP system, a huge speed gain was realized over the use of dynamic arrays. Now on Sun boxen and UV we don't use dimensioned arrays anymore. We've found that for ease of software maintenance, dynamic arrays are the best fit for us. Gordon J. Glorfield Sr. Applications Developer MAMSI (A UnitedHealth Company) 301-360-8839 [EMAIL PROTECTED] wrote on 05/13/2005 04:40:17 PM: I am by far from a 'smart person'. But when I was first learning I was told if you were only going to use values in the first few a/m or if was simply a short item, less than 10 or so a/m then you can use dynamic. Anything more than that use dimensioned. If you are going to use say a/m 50 and you use a dynamic array, every time it actually has to start at 1 and work through to find 50. Were if you use a dimensioned array it will go straight to (50). I was shown a nifty table when learning this where it showed all the values the program uses being put into buckets. If you use a dynamic read, it all goes into one bucket. If you use Dimensioned it each goes into it's own bucket. This is my 'simple' minded understanding. I am sure many more answers will be posted on this topic. Thanks, Marilyn A. Hilb Value Part, Inc Direct: 847-918-6099 Fax: 847-367-1892 [EMAIL PROTECTED] www.valuepart.com -Original Message- From: Stevenson, Charles [mailto:[EMAIL PROTECTED] Sent: Friday, May 13, 2005 2:50 PM To: u2-users@listserver.u2ug.org Subject: RE: [U2] I'm in an Array quandry, any suggestions... Maybe the Smart People on this list can give a good rule of thumb for deciding when to READU/WRITE vs. MATREADU/MATWRITE. After all these years, I still don't have one. [snip] This e-mail, including attachments, may include confidential and/or proprietary information, and may be used only by the person or entity to which it is addressed. If the reader of this e-mail is not the intended recipient or his or her authorized agent, the reader is hereby notified that any dissemination, distribution or copying of this e-mail is prohibited. If you have received this e-mail in error, please notify the sender by replying to this message and delete this e-mail immediately. --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Archives (was RE: [U2] Dymanic vs Dimenssioned)
Dan Fitzgerald wrote: Do we have archives somewhere? If it's fairly recent, (since Jan 2005?) mail-archive.com should have it: http://www.mail-archive.com/u2-users%40listserver.u2ug.org/ This one goes back further, but the search doesn't work as well: http://www.indexinfocus.com/ -- Wendy Smoak Applications Systems Analyst, Sr. Arizona State University, PA, IRM --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Dymanic vs Dimenssioned
That is correct. I think it was at release 7, a field cache pointer was introduced. If you walk down a dynamic array thus for i = 1 to n fieldStuff = dynArrayi next i the run-machine does not re-scan from the beginning of the string. It moves down the string remembering where it was. The performance is almost as good as using REMOVE. So if you have a large record with a lot of fields and you are only going to use the first few fields, a READ and i technique is faster than a MATREAD (which is basically a READ followed by a MATPARSE). I think they tweeked this some more at release 8 to include backward referencing and some other tricks. So are dimensioned arrays better than dynamic arrays, or the reverse? It depends on the situation, the data, the statistical likelihood of certain string lengths, whether or not it is an even numbered Tuesday that falls on the 23rd day of the Feast of the Goddess Eris, and who knows what else. Then things change at each release and everything we know, is wrong. It's like I used to tell my students when I was teaching the BASIC programming classes: Always remember that you should never believe any rule containing the words 'always' or 'never'. -- Regards, Clif ~~~ W. Clifton Oliver, CCP CLIFTON OLIVER ASSOCIATES Tel: +1 619 460 5678Web: www.oliver.com ~~~ On May 13, 2005, at 1:52 PM, Dan Fitzgerald wrote: Do we have archives somewhere? IIRC correctly, Glenn Herbert posted a great description of dynamic array optimization some time ago. I believe the upshot was, bowing to Yogi Berra on his 80th, that the difference ain't what it used to be. Our greatest duty in this life is to help others. And please, if you can't help them, could you at least not hurt them? - H.H. the Dalai Lama When buying selling are controlled by legislation, the first thing to be bought sold are the legislators - P.J. O'Rourke Dan Fitzgerald From: Marilyn Hilb [EMAIL PROTECTED] Reply-To: u2-users@listserver.u2ug.org To: u2-users@listserver.u2ug.org Subject: RE: [U2] Dymanic vs Dimenssioned Date: Fri, 13 May 2005 15:40:17 -0500 I am by far from a 'smart person'. But when I was first learning I was told if you were only going to use values in the first few a/m or if was simply a short item, less than 10 or so a/m then you can use dynamic. Anything more than that use dimensioned. If you are going to use say a/m 50 and you use a dynamic array, every time it actually has to start at 1 and work through to find 50. Were if you use a dimensioned array it will go straight to (50). I was shown a nifty table when learning this where it showed all the values the program uses being put into buckets. If you use a dynamic read, it all goes into one bucket. If you use Dimensioned it each goes into it's own bucket. This is my 'simple' minded understanding. I am sure many more answers will be posted on this topic. Thanks, Marilyn A. Hilb Value Part, Inc Direct: 847-918-6099 Fax: 847-367-1892 [EMAIL PROTECTED] www.valuepart.com -Original Message- From: Stevenson, Charles [mailto:[EMAIL PROTECTED] Sent: Friday, May 13, 2005 2:50 PM To: u2-users@listserver.u2ug.org Subject:RE: [U2] I'm in an Array quandry, any suggestions... Maybe the Smart People on this list can give a good rule of thumb for deciding when to READU/WRITE vs. MATREADU/MATWRITE. After all these years, I still don't have one. From: Richard Taylor We are faced with this same situation and the thought behind this truly baffles me. I will admit to some of the same bafflement. Why take a flexible, dynamic database system The syntax for dynamic arrays is more natural for the language, too (e.g., XYZ(17)1,5 vs. XYZ17,5). Readability makes for maintainability, generally the most important contributor to software quality. and force it to be fixed length. well, sorta. Each element of the dimensioned array is a variable length dynamic array. ( See my previous post for how to complicate your life by inserting attribute marks. ) This is what you are doing using dimensioned arrays and MATREADs. The most common justification I have heard is performance and this simply does not hold water. Within limits (but I don't know the limits). If you have a program that manipulates many attributes many times, then it makes sense to matread them into a dimensioned array up front, and matwrite them in the end, thereby limiting big string manipulations. People forget or newbies don't know that CUST.REC117 is really EXTRACT( CUST.REC, 117,0,0) or REPLACE(...,CUST.REC,117,0,0). That can be very expensive when you do that for many attributes many times, with large dynamic arrays. By contrast, each dimensioned array element has its own memory address, so references and assignments can jump straight to it. But I do not have a good appreciation for what limits, many, big really mean in my previous
RE: [U2] Dymanic vs Dimenssioned
From: Clifton Oliver Always remember that you should never believe any rule containing the words 'always' or 'never'. --- Or as I say in my classes now... There's a time and place for everything, and it's not always and not never. I would have used yours Clif, but if I follow the rule I can't believe it. ;-) -Kevin [EMAIL PROTECTED] http://www.PrecisOnline.com -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.11.9 - Release Date: 5/12/2005 --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Dymanic vs Dimenssioned
On May 13, 2005, at 4:38 PM, Kevin King wrote: From: Clifton Oliver Always remember that you should never believe any rule containing the words 'always' or 'never'. --- Or as I say in my classes now... There's a time and place for everything, and it's not always and not never. I would have used yours Clif, but if I follow the rule I can't believe it. ;-) -Kevin [EMAIL PROTECTED] http://www.PrecisOnline.com I was always amused to see which ones caught that and which ones just wrote it down in their notes. --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
Re: [U2] Dymanic vs Dimenssioned
In a message dated 5/13/2005 2:00:51 PM Pacific Daylight Time, [EMAIL PROTECTED] writes: I believe the upshot was, bowing to Yogi Berra on his 80th, that the difference ain't what it used to be. True and false. If you are processing, sequentially, elements of a list then it probably makes no difference. However most UPDATE programs actually touch elements in a semi-random fashion. So you might have something like Inventory(3) = price Inventory(10) = onhand Inventory(21) = lastpo This type of update, not being in order, would exhibit much greater speed than the same update using a dynamic array. That being said, it's possible that the majority of an UPDATE type process isn't actually pushing values into cells, but doing lots of other things that changing the type of array would not affect. But simply saying that it makes no difference in any case is not true. Will Johnson Fast Forward Technologies --- u2-users mailing list u2-users@listserver.u2ug.org To unsubscribe please visit http://listserver.u2ug.org/
