Re: Implement waiting for wal lsn replay: reloaded

10.03.2025 14:30, Alexander Korotkov пишет:
> On Fri, Feb 28, 2025 at 3:55 PM Yura Sokolov <y(dot)sokolov(at)postgrespro(dot)ru> wrote:
>> 28.02.2025 16:03, Yura Sokolov пишет:
>>> 17.02.2025 00:27, Alexander Korotkov wrote:
>>>> On Thu, Feb 6, 2025 at 10:31 AM Yura Sokolov <y(dot)sokolov(at)postgrespro(dot)ru> wrote:
>>>>> I briefly looked into patch and have couple of minor remarks:
>>>>>
>>>>> 1. I don't like `palloc` in the `WaitLSNWakeup`. I believe it wont issue
>>>>> problems, but still don't like it. I'd prefer to see local fixed array, say
>>>>> of 16 elements, and loop around remaining function body acting in batch of
>>>>> 16 wakeups. Doubtfully there will be more than 16 waiting clients often,
>>>>> and even then it wont be much heavier than fetching all at once.
>>>>
>>>> OK, I've refactored this to use static array of 16 size. palloc() is
>>>> used only if we don't fit static array.
>>>
>>> I've rebased patch and:
>>> - fixed compiler warning in wait.c ("maybe uninitialized 'result'").
>>> - made a loop without call to palloc in WaitLSNWakeup. It is with "goto" to
>>> keep indentation, perhaps `do {} while` would be better?
>>
>> And fixed:
>> 'WAIT' is marked as BARE_LABEL in kwlist.h, but it is missing from
>> gram.y's bare_label_keyword rule
>
> Thank you, Yura. I've further revised the patch. Mostly added the
> documentation including SQL command reference and few paragraphs in
> the high availability chapter explaining the read-your-writes
> consistency concept.

Good day, Alexander.

Looking "for the last time" to the patch I found there remains
`pg_wal_replay_wait` function in documentation and one comment.
So I fixed it in documentation, and removed sentence from comment.

Otherwise v6 is just rebased v5.

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regards
Yura Sokolov aka funny-falcon