Re: Logical Replication Memory Allocation Error - "invalid memory alloc request size" - Mailing list pgsql-general

From Max Madden
Subject Re: Logical Replication Memory Allocation Error - "invalid memory alloc request size"
Date
Msg-id CAD1FGCQmgLK9XqHfmkAR2+79oLBsJRYPQj0W-hirbZJRgzLVkg@mail.gmail.com
Whole thread Raw
In response to RE: Logical Replication Memory Allocation Error - "invalid memory alloc request size"  ("Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>)
List pgsql-general
Hi Hayato, 

Thank you for your reply.

We have rewritten as many of our transactions as possible to avoid using temporary tables, and so far, that seems to have resolved the problem. 

Thank you for your help. 

Many thanks,
 
Max

On Wed, Jun 11, 2025 at 3:31 AM Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com> wrote:
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 size 1238451248
> 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

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