Re: Problem with txid_snapshot_in/out() functionality

<p dir="ltr"><br /> On 12 Apr 2014 08:35, "Jan Wieck" <<a href="mailto:jan@wi3ck.info">jan@wi3ck.info</a>>
wrote:<br/> ><br /> > On 04/12/14 03:27, Heikki Linnakangas wrote:<br /> >><br /> >> On 04/12/2014
12:07AM, Jan Wieck wrote:<br /> >>><br /> >>> Hackers,<p dir="ltr">>> Hmm. Do we snapshots to
bestored in tables, and included in a dump? I<br /> >> don't think we can guarantee that will work, at least not
across<br/> >> versions, as the way we handle snapshot internally can change.<br /> ><br /> ><br /> > At
leastLondiste and Slony do store snapshots as well as xids in tables and assuming that the txid epoch is properly
bumped,that information is useful and valid after a restore.<p dir="ltr">As I understand it the epoch increments
wheneverthe xid wraps. <p dir="ltr">A physical restore would continue the same xid space in the same epoch which should
workfine as long as no system stores any txids outside the database from the "future".<p dir="ltr">A pg_restore would
starta new xid space from FirstNormalXid which would obviously not work with any stored txids.