[pgpool-general: 9420] Re: FATAL: failed to read kind from backend

[Tatsuo Ishii]

>> On Fri, Mar 28, 2025 at 2:59 AM Tatsuo Ishii <ishii at postgresql.org> wrote:
>> 
>>> >> > OK.  But what _is_ causing  the FATAL "kind mismatch" errors?
>>> >>
>>> >> Under investigation. I am failing to reproduce the problem.
>>> >>
>>> >
>>> > Thank you.
>>> >
>>> > The error _seems_ to be volume-related: happens more when the system is
>>> > busy.  (But maybe a busy system has more opportunity to trigger the bug.
>>>
>>> That's my thought too for now.
>>>
>>> > Would it help if I cranked up log_min_messages to DEBUG1 or even DEBUG2?
>>>
>>> Yes, please enable DEBUG1.
>>>
>> 
>> I was working on it before I saw your email. 😀   Gzip file sent directly
>> to you, with extract for just the pid that had the error.).
>> 
>> (Lord, but it generates a lot of log lines!)
> 
> Thanks.

Looking at the log file, I noticed that you are using the query cache
feature. To break down the issue, can you disable the query cache
feature?

memory_cache_enabled = off
enable_shared_relcache = off

("enable_shared_relcache = on" uses the query cache feature even if
"memory_cache_enabled = off").

Best reagards,
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp