Mike Matrigali wrote: >If java ever provides a way to directly queue I/O straight from >our buffer to disk with no intermediate data copy then it may >be important to use a page based log scheme. For now it looks >like the stream interfaces being used and the JVM's optimization >of those interfaces are working ok. A nice property of the current >log which we don't take advantage of is that since it is a stream, >we could dynamically change the size of the block of data we >write, increasing it as log activity increases. This sort of >happens with group commit where we will write less than a block >if a commit happens - but we never consider growing the buffers >bigger than the boot time size. > > > >From the number it does looks like performance is better is only in some cases(64k) . Considering the overhead involved in making writes aligned , like performing extra writes to handle unfilled page cases in short transactions. By implementing alligned log writes , logn transaction perfomance might improve but short transasction peformance is likely to degrade..
I agree that it may not be good idea to modify the logging system to perform alligned writes at least for now. Thanks -suresht
