Re: Snapshot synchronization, again...
Joachim Wieland <joe@mcknight.de>
From: Joachim Wieland <joe@mcknight.de>
To: Alvaro Herrera <alvherre@commandprompt.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2010-12-31T14:38:51Z
Lists: pgsql-hackers
On Fri, Dec 31, 2010 at 8:28 AM, Alvaro Herrera <alvherre@commandprompt.com> wrote: > A backend can have any number of snapshots registered, and those don't > allow GlobalXmin to advance. Consider an open cursor, for example. > Even if the rest of the transaction is read committed, the snapshot > registered by the open cursor still holds back GlobalXmin. My > (handwavy) idea is that whenever the transaction calls > pg_publish_snapshot(), said snapshot is registered, which makes it safe > to use even if the transaction continues to operate and obtain newer > snapshots. Cool, even better that this is taken care of already :-) Thanks, Joachim