Re: Database writing architecture

JB,

That would explain the raw partition writes, and I agree with you that on raw partitions both oracle and sybase take over the writing to disk. If you've looked at linux code, there are actual scheduling algorithms that depend on the location of the disk's actuator arm.

On a filesystem however, their higher level arcitectures come into play (at least I think so). My theory is that Sybase synchronizes the writing of the db-blocks and the writing of the log-blocks and that Oracle does not.

If you only write the logs and can reconstruct the db-blocks from only the log blocks, then you have the ability in a power failure to reconstruct the db-blocks. In normal operation, the db-blocks should be written a significant amount of time AFTER the log blocks to avoid data corruption.

If sybase writes the db blocks and log blocks at near simultaneity, then corruption can happen with power failure. My question is... Does this indeed happen?

--Jerry. Received on Fri Apr 12 1996 - 00:00:00 CEST