Re: POC: Cleaning up orphaned files using undo logs

On Wed, Jun 19, 2019 at 9:13 AM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> I think it's a fair point. We can keep pointer to
> UndoRecordTransaction(urec_progress, dbid, uur_next) and
> UndoRecordLogSwitch(urec_prevurp, urec_prevlogstart) in
> UnpackedUndoRecord and include them whenever undo record contain these
> headers. Transaction header in the first record of the transaction
> and log-switch header in the first record after undo-log switch during
> a transaction. IMHO uur_fxid, we can keep as part of the main
> UnpackedUndoRecord, because as part of the other work "Compression
> for undo records to consider rmgrid, xid,cid,reloid for each record",
> the FullTransactionId, will be present in every UnpackedUndoRecord
> (although it will not be stored in every undo record).

I agree that fxid needs to be set all the time.

I'm not sure I'm entirely following the rest of what you are saying
here, but let me say again that I don't think UnpackedUndoRecord
should include a bunch of stuff that callers (1) don't need to set
when inserting and (2) can't count on having set when fetching. Stuff
of that type should be handled in some way that spares clients of the
undo system from having to worry about it.

--
Robert Haas
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