On Tue, Aug 15, 2017 at 9:59 AM, Tomas Vondra <tomas.von...@2ndquadrant.com> wrote: >> I don't think so -- the "committed" and "invalid" meanings are >> effectively canceled when the "frozen" mask is present. >> >> I mean, "committed" and "invalid" contradict each other... > > FWIW I agree with Craig - the functions should output the masks raw, without > any filtering. The reason is that when you're investigating data corruption > or unexpected behavior, all this is very useful when reasoning about what > might (not) have happened. > > Or at least make the filtering optional.
I don't think "filtering" is the right way to think about it. It's just labeling each combination of bits with the meaning appropriate to that combination of bits. I mean, if you were displaying the contents of a CLOG entry, would you want the value 3 to be displayed as COMMITTED ABORTED SUBCOMMITTED because TRANSACTION_STATUS_COMMITTED|TRANSACTION_STATUS_ABORTED == TRANSACTION_STATUS_SUB_COMMITTED? I realize that you may be used to thinking of the HEAP_XMIN_COMMITTED and HEAP_XMAX_COMMITTED bits as two separate bits, but that's not really true any more. They're a 2-bit field that can have one of four values: committed, aborted, frozen, or none of the above. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
