Re: Truncate logs by max_log_size

On Thu, Sep 26, 2024, at 3:30 PM, diPhantxm wrote:
> I would like to suggest a patch to truncate some long queries. I believe sometimes there is no need to log a query containing some gigabytes of blob, for example. In patch a new parameter, named max_log_size, is introduced. It defines the maximum size of logged query, in bytes. Everything beyond that size is truncated.

I don't know how useful is this proposal. IMO the whole query is usually
crucial for an analysis. Let's say you arbitrarily provide max_log_size = 100
but it means you cannot see a WHERE clause and you have a performance issue in
that query. It won't be possible to obtain the whole query for an EXPLAIN. It
would break audit systems that requires the whole query. I don't know if there
are some log-based replication systems but it would break such tools too.

There are other ways to avoid logging such long queries. The GRANT ... ON
PARAMETER and SET LOCAL commands are your friends. Hence, you can disable
specific long queries even if you are not a superuser.

If your main problem is disk space, you can adjust the rotation settings or have
an external tool to manage your log files (or even use syslog).

--
Euler Taveira
EDB https://www.enterprisedb.com/