Fuzzy Operations : Some clarity from Informix

Gang, Following up on the Fuzzy Operation issue : Specifically, if pages affected by fuzzy operations are not physically logged, how will recovery be effected in case a crash occurs during a write of a page, leaving the page "inconsistent". The matter was raised with Informix. This is the jist of their reply. 1. Given that v9.2 no longer physically logs these pages, how will recovery in the "partial-write" example be accomplished? Informix> Restore from a previous backup. However, Informix believes that the possibility of a partial-write is negligible to zero. Tech-Support knows of no such cases since reduced physical logging was first implemented (though not documented) in late v7.2 or v7.3 (the tech engineer was not sure about the exact version). My comments> I confirmed that "reduced" physical logging has been implemented in v7.31UC2 on HP10.20. In fact, in the tests I carried out, v7.31 carried out identical physical logging as v9.2 under identical insert & update scenarios. 2. If we say that such a partial write scenario is not being catered to because the possibility of it occurring is so remote, why do we need the physical log at all? All that needs to be done is to locate the point in the Logical log where data was last consistent (the latest full checkpoint) and apply all transactions from there, finally rolling back the un-committed ones. Informix> This is true. Consideration is being given to getting rid of the Physical log in future versions, possibly v9.3. My final comments. I'm beginning to believe that Informix's original physical logging strategy was excellent in situations that existed, say, 10 years ago. Improvements in HDD technology and market pressures from other Database Vendor that did not carry out physical logging (and thus had better performance) have caused Informix to rethink this strategy. Cheers Rudy