Re: Data Block Cleanup??
Date: Thu, 7 Oct 1993 13:31:58 GMT
Message-ID: <CEJ49B.8wA_at_world.std.com>
In article <10YHB6DW_at_gwdu03.gwdg.de> plewe_at_dl.mpi-dortmund.mpg.de (J.Plewe) writes:
>There actually is no extra step. Resetting the transaction entry is ONE
>action, no matter when it is done.
>The manner of cleaning transaction entries you mention would mean for
>Oracle to keep track of wether blocks are still in the SGA or already
>flushed to disk. THIS is an extra effort.
>Clearing the transaction entry with the next SELECT on a block implicitely
>makes sure that the block is in memory. Seen from this point, it is the
>most simple way to do it.
It may be the most simple, but also very inefficient. In many situations this would lead to extra, gratuitous disk writes. It should be easy to do this cleanup prior to purging a block from memory. I would be very surprised if this wasn't the case, but I will look into it anyway.
-- Jonathan Edwards edwards_at_intranet.com IntraNet, Inc 617-527-7020Received on Thu Oct 07 1993 - 14:31:58 CET