View Full Version : Database Buffers
01-14-2007, 11:50 PM
This TechTip article (Buffering-Friend or Foe?) should be of help to you: Mike Savino "TechTip: Buffering--Friend or Foe?" 7/16/04 7:52am (/firstname.lastname@example.orgVMfHb6dae.1@.6aecd92d&phpMyAdmin=MzvdqLOMiN7HL4yz2OU82BJvkG9) I'd say changing the Force Ratio parameter of the table (physical file object) should address your problem.
01-17-2007, 06:29 AM
Thanks for the info. I read the article and ran some tests and performance is definitely an issue. The article talks about buffering as if other programs don't have access to the data while the records are being buffered. But in my situation any an and all updates/writes throughout the day were accessible to other programs, yet these records were still lost after the power outage. I ran tests on the F spec with output only specified on a file and buffered records were invisible until the program ended. What am i missing? Thanks.
01-22-2007, 05:20 AM
The principle in the article should also apply to the case of multiple programs accessing a table. Did you try CHGPF FILE(MYLIB/MYFILE) FRCRATIO(1) on those files in issue and tested your application again ? If so and the missing data still occured, buffering should not be an issue. U mentioned using SQL to manipulate the data. What kind of program runs these SQL statements (SQL from ODBC/JDBC connection or embedded SQL in RPG/COBOL/C or ...)? If U R using embedded SQL in RPG, please read the following articles which may help : Article 1 on RPG program with embedded SQL by Gantner and Paris (http://www.ibmsystemsmagazine.com/ME2/Audiences/dirmod.asp?sid=&nm=&type=Publishing&mod=Publications%3A%3AArticle&mid=8F3A7027421841978F18BE895F87F791&tier=4&id=E78569EB8C11418086F5158184AD1A48&AudID=1E8FEE745A284521B6CFB3FD70B49099) and Article 2 on RPG program with embedded SQL by Gantner and Paris (http://www.ibmsystemsmagazine.com/ME2/Audiences/dirmod.asp?sid=&nm=&type=Publishing&mod=Publications%3A%3AArticle&mid=8F3A7027421841978F18BE895F87F791&tier=4&id=0F050024CBE748C28C3A0B5E8C2502E6&AudID=1E8FEE745A284521B6CFB3FD70B49099)
01-22-2007, 05:20 AM
We recently had a problem where our iSeries lost power and after being brought back up, a few files had some missing records. These files were not journaled, nor did the programs using these files for I/O were compiled with commitment control. These files were created using SQL Create command. We have a few theories as to what happened but they are just that, theories. Does anybody have an idea why we would lose records on a only a few files. These files are written to, updated with SQL. During the course of the day, any updates or writes were accessible by other programs but after the iSeries went down the data disappeared. Any input is appreciated. Let me know if there is more information needed. Thanks.
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