PM82173: HOURGLASS DOES NOT MODIFY TIME FOR DB2 COLUMNS DEFINED WITH TIMESTAMP NOT NULL GENERATED ALWAYS FOR EACH ROW ON UPDATE
Closed as user error.
Hourglass does not modify time for DB2 Columns defined with TIMESTAMP NOT NULL GENERATED ALWAYS FOR EACH ROW ON UPDATE Testcase: CREATE TABLE Q039395.TYUTSHG ( TEST CHAR(5) NOT NULL FOR SBCS DATA ,TS_HG TIMESTAMP NOT NULL WITH DEFAULT ,UPDATED_TS_HG TIMESTAMP NOT NULL GENERATED ALWAYS FOR EACH ROW ON UPDATE AS ROW CHANGE TIMESTAMP ) IN DQ039395.SQ039395 CCSID EBCDIC NOT VOLATILE APPEND NO ; INSERT INTO Q039395.TYUTSHG (TEST) VALUES ( 'AAAAA' ); INSERT INTO Q039395.TYUTSHG (TEST) VALUES ( 'BBBBB' ); INSERT INTO Q039395.TYUTSHG (TEST) VALUES ( 'CCCCC' ); INSERT INTO Q039395.TYUTSHG (TEST) VALUES ( 'DDDDD' ); INSERT INTO Q039395.TYUTSHG (TEST) VALUES ( 'EEEEE' ); As you can see the Timestamp value by UPDATED_TS_HG is wrong by INSERT too.
As we understand it, you believe that HourGlass should intercept time requests related to the retrieval of the timestamp value that DB2 stores in Row Change Timestamp Column (RCTC). After much internal discussion, we don't believe that we should be so. It seems to us as though the RCTC value, especially when supplied by DB2 itself, should always contain the actual, unmodified system time-of-day value. One very good reason for this is the fact that HourGlass availability is not necessarily guaranteed. This raises the possibility that some RCTC values could contain HourGlass-modified values, and other RCTC values, even in the same row, could contain the normal, unmodified system time-of-day value, which would create an inconsistency in the meaning of the RCTC column itself. If we understand it correctly, DB2 does provide an option for the user application to supply the RCTC value to DB2. In that case, the application could retrieve the timestamp value via the Current Timestamp special register, which HourGlass does currently modify, examine the value just retrieved to ensure that it is what the application is expecting, and either give the timestamp value to DB2 for the RCTC, or handle the error condition. It seems to me that this procedure would minimize problems for both the client and IBM.
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APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
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