Re: old_snapshot_threshold documentation - Mailing list pgsql-hackers

From Kevin Grittner
Subject Re: old_snapshot_threshold documentation
Date
Msg-id CACjxUsNuFP0kUGn2rzj=NMXOODFL80wGqtaN=GmARwVsdQVHeQ@mail.gmail.com
Whole thread Raw
In response to old_snapshot_threshold documentation  (Peter Eisentraut <peter.eisentraut@2ndquadrant.com>)
List pgsql-hackers
On Fri, Aug 26, 2016 at 1:34 PM, Peter Eisentraut
<peter.eisentraut@2ndquadrant.com> wrote:
> I doubt the documentation for old_snapshot_threshold is going to be
> understood by many ordinary users.  What is a "snapshot", first of all?
> Why would a snapshot be old?  Why is that a problem?  What can I do to
> avoid it?  What are the circumstances in practice where this issue would
> arise, and what are the trade-offs?  Where can I see existing snapshots
> and how old they are?

I'll put something together to improve that.  I think largely that
will consist of references to other sections of the documentation,
like MVCC, vacuuming, pg_stat_activity, etc.

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



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