Re: XLog: how to log? - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: XLog: how to log?
Date
Msg-id 200405111533.i4BFX9U26374@candle.pha.pa.us
Whole thread Raw
In response to Re: XLog: how to log?  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: XLog: how to log?
List pgsql-hackers
Tom Lane wrote:
> Alvaro Herrera <alvherre@dcc.uchile.cl> writes:
> > Hmm ... I think it should be forbidden to quote a subtrans Xid as
> > rollforward point.  Not sure if that can be done though, or how to do
> > it.
> 
> Seems like a nonissue, unless the XLOG trace makes a subtrans look the
> same as a main trans, which it'd not do would it?
> 
> We could allow specification of a subtrans ID to be interpreted the same
> as specification of its parent main trans.  Dunno if that's actually
> useful to anyone.  Actually, I'd think that people would generally
> specify recovery up to a particular timestamp, and not be interested in
> xact numbers at all ...

I don't think timestamp is going to be precise enough.  Basically I can
see someone saying I want recovery up to 4am, but anything more specific
will need xid.  I suggested that we write an xlog dump tool so you can
see the xids (with some xid details) and rough timestamps stored in the
WAL file and choose the xid for recovery.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
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