Re: Synchronizing slots from primary to standby - Mailing list pgsql-hackers

From Amit Kapila
Subject Re: Synchronizing slots from primary to standby
Date
Msg-id CAA4eK1Jq9hFgrSejVRa107YxqaGJg12sutRZQjxFiveGq1bAtg@mail.gmail.com
Whole thread Raw
In response to Re: Synchronizing slots from primary to standby  (Bertrand Drouvot <bertranddrouvot.pg@gmail.com>)
List pgsql-hackers
On Mon, Mar 4, 2024 at 4:52 PM Bertrand Drouvot
<bertranddrouvot.pg@gmail.com> wrote:
>
> On Sun, Mar 03, 2024 at 07:56:32AM +0000, Zhijie Hou (Fujitsu) wrote:
> > Here is the V104 patch which addressed above and Peter's comments.
>
> Thanks!
>
>
> 4 ===
>
> +       /*
> +        * Don't need to wait for the standbys to catch up if there is no value in
> +        * standby_slot_names.
> +        */
> +       if (standby_slot_names_list == NIL)
> +               return true;
> +
> +       /*
> +        * Don't need to wait for the standbys to catch up if we are on a standby
> +        * server, since we do not support syncing slots to cascading standbys.
> +        */
> +       if (RecoveryInProgress())
> +               return true;
> +
> +       /*
> +        * Don't need to wait for the standbys to catch up if they are already
> +        * beyond the specified WAL location.
> +        */
> +       if (!XLogRecPtrIsInvalid(standby_slot_oldest_flush_lsn) &&
> +               standby_slot_oldest_flush_lsn >= wait_for_lsn)
> +               return true;
>
> What about using OR conditions instead?
>

I think we can use but it seems code is easier to follow this way but
this is just a matter of personal choice.

> 5 ===
>
> +static bool
> +NeedToWaitForStandby(XLogRecPtr target_lsn, XLogRecPtr flushed_lsn,
> +                                        uint32 *wait_event)
>
> Not a big deal but does it need to return a bool? (I mean it all depends of
> the *wait_event value). Is it for better code readability in the caller?
>

Yes, I think so.  Adding checks based on wait_events sounds a bit awkward.

--
With Regards,
Amit Kapila.



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