Thread: [HACKERS] Comment in snapbuild.c file
Hi all, In snapbuild.c file, there is a comment as follows. * NB: Because of that xmax can be lower than xmin, because we only * increase xmax when a catalog modifying transaction commits. While odd * looking, it's correct and actually more efficient this way since we hit * fast paths in tqual.c. */ Maybe we can get rid of the second "because" in the first sentence? Attached patch. Regards, -- Masahiko Sawada NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
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Masahiko Sawada wrote: > Hi all, > > In snapbuild.c file, there is a comment as follows. > > * NB: Because of that xmax can be lower than xmin, because we only > * increase xmax when a catalog modifying transaction commits. While odd > * looking, it's correct and actually more efficient this way since we hit > * fast paths in tqual.c. > */ > > Maybe we can get rid of the second "because" in the first sentence? I think the whole para needs to be rethought. I propose this: * NB: We only increase xmax when a catalog-modifying transaction commits * (see SnapBuildCommitTxn). Because of this, xmaxcan be lower than xmin, * which looks odd but is correct and actually more efficient, since we hit * fast paths in tqual.c. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
Alvaro Herrera wrote: > Masahiko Sawada wrote: > > Hi all, > > > > In snapbuild.c file, there is a comment as follows. > > > > * NB: Because of that xmax can be lower than xmin, because we only > > * increase xmax when a catalog modifying transaction commits. While odd > > * looking, it's correct and actually more efficient this way since we hit > > * fast paths in tqual.c. > > */ > > I think the whole para needs to be rethought. Pushed, thanks. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
On Sun, Aug 13, 2017 at 12:28 PM, Alvaro Herrera <alvherre@2ndquadrant.com> wrote: > Alvaro Herrera wrote: >> Masahiko Sawada wrote: >> > Hi all, >> > >> > In snapbuild.c file, there is a comment as follows. >> > >> > * NB: Because of that xmax can be lower than xmin, because we only >> > * increase xmax when a catalog modifying transaction commits. While odd >> > * looking, it's correct and actually more efficient this way since we hit >> > * fast paths in tqual.c. >> > */ >> >> I think the whole para needs to be rethought. > > Pushed, thanks. > Sorry for the late response. I agreed with your proposal. Thank you for committing! Regards, -- Masahiko Sawada NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center