On 08/10/2015 10:31 AM, Simon Riggs wrote: > Freezing is not a necessary pre-condition for either of those things, I > am happy to say. There is confusion here because for ( 1 ) the shrink > was performed after freezing, but when you have access to the epoch > there is no need for exhaustive freezing - only in special cases, as > noted. If we are lucky those special cases will mean a massive reduction > in I/O. For ( 2 ) a normal VACUUM is sufficient and as Robert observes, > maybe just HOT is enough.
Yeah, saw your explanation on this on the other thread. Good point. Question: does regular vacuum update the visibility map in the same way vacuum freeze does? -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
