Re: Question about WAL and XID

Boszormenyi Zoltan wrote:
> am I right that an XID is global across the whole DB cluster
> under the same $PGDATA?

Yes.

> I am asking this because I need to check
>     TransactionIdDidCommit(XLogRecord->xl_xid)
> from the walreciver. Can I expect it to work on any
> xl_xid that walreceiver encounters?

Walreceiver is only responsible for receiving the WAL from the master
server, and write to disk. It doesn't apply the log, it doesn't look
into the contents at all. So TransactionIdDidCommit(XLogRecord->xl_xid)
always returns false on WAL it has received, because it hasn't been
applied yet.

What are you trying to do?

--  Heikki Linnakangas EnterpriseDB   http://www.enterprisedb.com