Re: typos in HS source code comment

On Fri, Aug 13, 2010 at 8:28 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> I've committed all of this except for the following, which I'm not
> certain is correct:

Thanks for the commit.

> --- a/src/backend/access/transam/clog.c
> +++ b/src/backend/access/transam/clog.c
> @@ -355,10 +355,10 @@ TransactionIdSetStatusBit(TransactionId xid, XidStatus sta
>        /*
>         * Update the group LSN if the transaction completion LSN is higher.
>         *
> -        * Note: lsn will be invalid when supplied during InRecovery processing,
> -        * so we don't need to do anything special to avoid LSN updates during
> -        * recovery. After recovery completes the next clog change will set the
> -        * LSN correctly.
> +        * Note: lsn will be invalid when supplied while we're performing
> +        * recovery but hot standby is disabled, so we don't need to do
> +        * anything special to avoid LSN updates in that case. After recovery
> +        * completes the next clog change will set the LSN correctly.
>         */
>        if (!XLogRecPtrIsInvalid(lsn))
>        {
>
> TransactionIdSetStatusBit is called from TransactionIdSetPageStatus,
> which seems to think that the validity of lsn is based on whether
> we're doing an async commit.  Your change may be correct, but I'm not
> certain of it...

Before 9.0, since xact_redo_commit always calls TransactionIdCommitTree,
TransactionIdSetStatusBit always receives InvalidXLogRecPtr. In 9.0,
xact_redo_commit calls TransactionIdCommitTree only when hot standby is
disabled. OTOH, when hot standby is enabled, xact_redo_commit calls
TransactionIdAsyncCommitTree, so TransactionIdSetStatusBit receives the
valid lsn.

Regards,

PS. I'll be unable to read hackers from Aug 13th to 20th because of
a vacation.

--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center