RE: Logical Replication Memory Allocation Error - "invalid memory alloc request size"

Dear Max,

Thanks for the report.

> The initial snapshot and data copy complete successfully for all tables. However, anywhere from 5
> minutes to 2 hours after the initial sync, the subscription consistently fails with memory allocation errors like:
>
> ```
> 2025-06-10 14:14:56.800 UTC [299] ERROR: could not receive data from WAL stream: ERROR: invalid memory alloc request
size1238451248 
 
> 2025-06-10 14:14:56.805 UTC [1] LOG: background worker "logical replication worker" (PID 299) exited with exit code
1
> ```

I think this is a known postgres bug which has been also reported at [1]. We are discussing
how we fix. Typically this can happen when there are lots of concurrent transactions
and they have DDLs. IIUC there are no good workaround for now - any parameters can't
avoid the failure. Only you can reduce them.

I'm happy if you apply the patch posted at [1] and confirms the issue can be solved, but...
seems difficult because you are in the managed env.

[1]: https://www.postgresql.org/message-id/CALDaNm0TaTPuza7Fa%2BDRMzL%2BmqK3%2B7RVEvFiRoDJbU2vkJESwg%40mail.gmail.com

Best regards,
Hayato Kuroda
FUJITSU LIMITED