From: Vikram A (vikkiatbiplyahoo.in)
Date: Tue Feb 23 2010 - 22:15:16 CST

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Sirs, Because one table will hold the large amount of data, only the recent data will be used for transactions; so rest of the old records are remain same with out any transaction. So we have decided to go for year based storage; here even old records can be taken out by join queries. I hope you experts will agree with this. Or your comments and suggestions are welcome for the better design. Thank you VIKRAM A ________________________________ From: Jerry Schwartz <jschwartzthe-infoshop.com> To: Vikram A <vikkiatbiplyahoo.in> Cc: Johan De Meersman <vegivamptuxera.be>; MY SQL Mailing list <mysqllists.mysql.com> Sent: Tue, 23 February, 2010 3:53:38 AM Subject: RE: how things get messed up I thought I had replied publicly to Johan’s suggestion, with some personal experience. He’s absolutely right, that would give you a solution that would be completely transparent to your application and therefore much easier to implement. You could keep re-arranging your partitions as necessary. I, myself, have never used portioning so I hope someone with experience will chime in here. One disadvantage is that all of your data would be in one database, making your backups bigger and bigger. If you used a separate database as an archive, the archive database wouldn’t have to be backed up very often. I never did get a good feel for how big your database will be. Even if you’re talking about IIT, and assuming 100000 students, 6 classes per semester, three semesters, per year, 20 years of history, you’re going to have 36 million class records. I think there are much bigger databases running quite well. Regards, Jerry Schwartz The Infoshop by Global Information Incorporated 195 Farmington Ave. Farmington, CT 06032 860.674.8796 / FAX: 860.674.8341 www.the-infoshop.com From:Vikram A [mailto:vikkiatbiplyahoo.in] Sent: Friday, February 19, 2010 11:17 PM To: Jerry Schwartz Cc: Johan De Meersman Subject: Re: how things get messed up Dear Sir, I agree with the solution proposed. But one of the member[Johan De Meersman<vegivamptuxera.be>] of this list has commented it. Do you have any opposition/Suggestions? Thank you VIKRAM A ________________________________ From:Jerry Schwartz <jschwartzthe-infoshop.com> To: Vikram A <vikkiatbiplyahoo.in> Cc: MY SQL Mailing list <mysqllists.mysql.com> Sent: Thu, 18 February, 2010 9:54:57 PM Subject: RE: how things get messed up From:Vikram A [mailto:vikkiatbiplyahoo.in] Sent: Wednesday, February 17, 2010 11:41 PM To: Jerry Schwartz Cc: MY SQL Mailing list Subject: Re: how things get messed up Dear Jerry Schwartz We have applications for colleges in India. The same idea of having single table for manipulating students records. but we are not following archiving concept. Ex stupersonal. and stuclass these tables are playing wide role in our application. After 7 years now there are 9000 records[postgresql backend] are there in the table. Because of this the entire application [ Fees, attendance, exams etc] performance is getting down. For the remedy of this I proposed this year wise architecture for our new version [mysql]. [JS] You have 9000 records? That should not slow down any application. I must not understand you. I have problem in year wise also, i have number of mutual related tables for students such as stu_last_studies, stu_family_details, stu_address, stu_extracurri and so on. If i go for year basisis i have to make all the above tables also year basis. Hence, I feel it difficult have such number of tables after few years. [JS] I did not mean that you should have tables for each year. I was suggesting that you have tables for recent data and tables for archived data. As you said the archive system, can you the idea about the archive system[If needed i will give the table structures]. [JS] This is best described with a picture. Here is a small example of what I meant: `student_master_table` (all years) /\ / \ `grades_current` `grades_archive` | / `class_master_table` The structures of the two grades tables should be almost the same, something like grade_id <autoincrement in grades_current only> student_id <index> class_id <index> class_start_date grade_received You would add new grade records to the `grades_current` table. Now, suppose that you don’t usually need data more than five years old. Once a year you would run these queries: INSERT INTO `grades_archive` SELECT * FROM `grades_current` WHERE `class_start_date` < YEAR(DATE_SUB(NOW(), INTERVAL 4 YEAR)); DELETE FROM `grades_current` WHERE `class_start_date` < YEAR(DATE_SUB(NOW(), INTERVAL 4 YEAR)); That would keep the `grades_current` table small. If you want to find a student’s recent grade history, you would use a query like SELECT * FROM `grades_current` WHERE `student_id` = 12345; If you decide that you need a student’s complete history, you could do SELECT * FROM `grades_current` WHERE `student_id` = 12345 UNION ALL SELECT * FROM `grades_archive` WHERE `student_id` = 12345; That is a quick outline of what I was saying. I don’t know how big your database is, so I can’t begin to guess whether or not this is necessary. On my desktop computer, where I do my testing, I have two tables: one has about 104000 records, the other has about 200000 records. The query SELECT `prod`.`prod_num`, `prod_price`.`prod_price_del_format`, `prod_price`.`prod_price_end_price` FROM `prod` JOIN `prod_price` ON `prod`.`prod_id` = `prod_price`.`prod_id` WHERE `prod`.`prod_num` = 40967; took .70 seconds. Repeating the same query with different values of `prod_num` gave increasingly faster results, showing that caching is working as expected: after three such queries, the response time was .14 seconds. I understand that schools in India can be very, very big; so perhaps you need an archive scheme such as the one I described. In fact, it might be useful to extend this whole concept to using an archive database, rather than archive tables within the same database. The database engine wouldn’t really care, but since the archive database wouldn’t change very often you wouldn’t have to back it up very often, either. Regards, Jerry Schwartz The Infoshop by Global Information Incorporated 195 Farmington Ave. Farmington, CT 06032 860.674.8796 / FAX: 860.674.8341 www.the-infoshop.com It will be grate help to me. Thank you VIKRAM A ________________________________ From:Jerry Schwartz <jschwartzthe-infoshop.com> To: Vikram A <vikkiatbiplyahoo.in>; Johan De Meersman <vegivamptuxera.be> Cc: MY SQL Mailing list <mysqllists.mysql.com> Sent: Tue, 16 February, 2010 9:32:22 PM Subject: RE: how things get messed up >-----Original Message----- >From: Vikram A [mailto:vikkiatbiplyahoo.in] >Sent: Friday, February 12, 2010 4:13 AM >To: Johan De Meersman >Cc: MY SQL Mailing list >Subject: Re: how things get messed up > >Sir, > >Thanks for your suggestion, >I will go for blob storage, because our application will maintain the data on >yearly basis[stupersonal2008, stupersonal2009 etc.]. So i feel we may not >face >such kind of performance issue in our application. > [JS] It sounds like you are planning to have one table per year. Regardless of where you put your blobs, I think that is a bad idea from a design standpoint. It will make it harder to find historical information. If your database is relatively small, then I'd just keep everything in one table. If it is big, then roll data that is five years old into an archive table. That will give you only two places, and an easy-to-follow rule to tell you where to look. Regards, Jerry Schwartz The Infoshop by Global Information Incorporated 195 Farmington Ave. Farmington, CT 06032 860.674.8796 / FAX: 860.674.8341 www.the-infoshop.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=vikkiatbiplyahoo.in ________________________________ Your Mail works best with the New Yahoo Optimized IE8. Get it NOW!. ________________________________ The INTERNET now has a personality. YOURS! See your Yahoo! Homepage. Your Mail works best with the New Yahoo Optimized IE8. Get it NOW! http://downloads.yahoo.com/in/internetexplorer/

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