On 2017-09-16 14:30:21 -0400, Tom Lane wrote: > Andres Freund <and...@anarazel.de> writes: > > Looking into it. > > I wonder whether we shouldn't just revert this patch altogether. > Certainly, extra reads of pg_control are not a noticeable performance > problem.
The problem is that the patch that makes the segment size configurable also adds a bunch more ordering constraints due to the fact that the contents of the control file influence how much shared buffers are needed (via wal_buffers = -1, which requires the segment size, which is read from the control file). Reading things in the wrong order leads to bad results too. > I'm now quite worried about whether we aren't introducing > hazards of using stale values from the file; if a system crash isn't > enough to get it to flush its cache, then what is? I don't think the problem here is stale values, it's "just" a stale pointer pointing into shared memory that gets reiniitalized? Greetings, Andres Freund -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
