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From: Heikki Linnakangas on 6 Apr 2010 05:00
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?

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

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From: Boszormenyi Zoltan on 6 Apr 2010 05:08
Hi,

Heikki Linnakangas �rta:
> 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.
>

I guessed so, I intended to collect the xl_xid values in a cache array
and check periodically.

> What are you trying to do?
>

Synchronous replication. :-)

Best regards,
Zolt�n B�sz�rm�nyi

--
Bible has answers for everything. Proof:
"But let your communication be, Yea, yea; Nay, nay: for whatsoever is more
than these cometh of evil." (Matthew 5:37) - basics of digital technology.
"May your kingdom come" - superficial description of plate tectonics

----------------------------------
Zolt�n B�sz�rm�nyi
Cybertec Sch�nig & Sch�nig GmbH
http://www.postgresql.at/


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