Re: [HACKERS] logical decoding of two-phase transactions

On Sun, Sep 20, 2020 at 11:01 AM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
> On Fri, Sep 18, 2020 at 6:02 PM Ajin Cherian <itsajin(at)gmail(dot)com> wrote:
> >
>
> 3.
>
> + /*
> + * If it's ROLLBACK PREPARED then handle it via callbacks.
> + */
> + if (TransactionIdIsValid(xid) &&
> + !SnapBuildXactNeedsSkip(ctx->snapshot_builder, buf->origptr) &&
> + parsed->dbId == ctx->slot->data.database &&
> + !FilterByOrigin(ctx, origin_id) &&
> + ReorderBufferTxnIsPrepared(ctx->reorder, xid, parsed->twophase_gid))
> + {
> + ReorderBufferFinishPrepared(ctx->reorder, xid, buf->origptr, buf->endptr,
> + commit_time, origin_id, origin_lsn,
> + parsed->twophase_gid, false);
> + return;
> + }
>
>
> I think we have already checked !SnapBuildXactNeedsSkip, parsed->dbId
> == ctx->slot->data.database and !FilterByOrigin in DecodePrepare
> so if those are not true then we wouldn't have prepared this
> transaction i.e. ReorderBufferTxnIsPrepared will be false so why do we
> need
> to recheck this conditions.
>

Yeah, probably we should have Assert for below three conditions:
+ !SnapBuildXactNeedsSkip(ctx->snapshot_builder, buf->origptr) &&
+ parsed->dbId == ctx->slot->data.database &&
+ !FilterByOrigin(ctx, origin_id) &&

Your other comments make sense to me.

--
With Regards,
Amit Kapila.