Re: logical replication: restart_lsn can go backwards (and more), seems broken since 9.4

On 11/14/24 00:33, Masahiko Sawada wrote:
> On Wed, Nov 13, 2024 at 3:53 AM Tomas Vondra <tomas@vondra.me> wrote:
>>
>>
>>
>> On 11/13/24 10:38, Amit Kapila wrote:
>>> On Tue, Nov 12, 2024 at 6:29 PM Tomas Vondra <tomas@vondra.me> wrote:
>>>>
>>>> Sure, maybe fixing LogicalIncreaseRestartDecodingForSlot() is enough to
>>>> fix this particular case. But I'd be happier if we could also add
>>>> asserts checking the LSN advances, to detect similar issues that we may
>>>> be unaware of yet.
>>>>
>>>
>>> As most of us lean towards fixing
>>> LogicalIncreaseRestartDecodingForSlot(), let's fix that in the HEAD
>>> and back branches. Separately we can consider other asserts just for
>>> HEAD that you think will make the code robust and help avoid such bugs
>>> in the future.
>>>
>>
>> +1 to that
>>
> 
> +1.
> 
> Tomas, are you going to update the patch you shared before[1] or shall I?
> 

Please feel free to take over. I'm busy with some other stuff and the
initial analysis was done by you anyway.


regards

-- 
Tomas Vondra