On Tue, Jul 26, 2016 at 05:42:43PM -0400, Chapman Flack wrote: > Even so, I'd be curious whether it would break anything to have > xlp_pageaddr simply set to InvalidXLogRecPtr in the dummy zero > pages written to fill out a segment. At least until it's felt > that archive_timeout has been so decidedly obsoleted by streaming > replication that it is removed, and the log-tail zeroing code > with it. > > That at least would eliminate the risk of anyone else repeating > my astonishment. :) I had read that 9.4 added built-in log-zeroing > code, and my first reaction was "cool! that may make the compression > technique we're using unnecessary, but certainly can't make it worse" > only to discover that it did, by ~ 300x, becoming now 3x *worse* than > plain gzip, which itself is ~ 100x worse than what we had.
My guess is that the bytes are there to detect problems where a 512-byte disk sector is zeroed by a disk failure. I don't see use changing that for the use-case you have described. -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + As you are, so once was I. As I am, so you will be. + + Ancient Roman grave inscription + -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers