On 01/15/2014 06:01 AM, Jim Nasby wrote:
For the sake of completeness... it's theoretically silly that Postgres
is doing all this stuff with WAL when the filesystem is doing something
very similar with it's journal. And an SSD drive (and next generation
spinning rust) is doing the same thing *again* in it's own journal.
If all 3 communities (or even just 2 of them!) could agree on the
necessary interface a tremendous amount of this duplicated technology
could be eliminated.
That said, I rather doubt the Postgres community would go this route,
not so much because of the presumably massive changes needed, but more
because our community is not a fan of restricting our users to things
like "Thou shalt use a journaled FS or risk all thy data!"
The WAL is also used for continuous archiving and replication, not just
crash recovery. We could skip full-page-writes, though, if we knew that
the underlying filesystem/storage is guaranteeing that a write() is atomic.
It might be useful for PostgreSQL somehow tell the filesystem that we're
taking care of WAL-logging, so that the filesystem doesn't need to.
- Heikki
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
