Re: Snapshot synchronization, again... - Mailing list pgsql-hackers

From Joachim Wieland
Subject Re: Snapshot synchronization, again...
Date
Msg-id AANLkTiktRBU5M6=Zgfmodn=ZX5VkZm=K2+_TdLxhYkC0@mail.gmail.com
Whole thread Raw
In response to Re: Snapshot synchronization, again...  (Alvaro Herrera <alvherre@commandprompt.com>)
List 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


pgsql-hackers by date:

Previous
From: Magnus Hagander
Date:
Subject: Re: Streaming replication as a separate permissions
Next
From: Simon Riggs
Date:
Subject: Re: Sync Rep Design