Re: Truncate logs by max_log_size

On 09/04/2026 20:11, Fujii Masao wrote:
> +$node->append_conf('postgresql.conf', "log_statement = 'all'\n");
> 
> This doesn't seem necessary, since $node->init already sets
> log_statement = 'all'.


Removed.
Most likely still leftovers from previous attempts.

> +$node->append_conf('postgresql.conf', "log_statement_max_length = 20\n");
> +$node->reload();
> +my $log_offset = -s $node->logfile;
> +$node->psql('postgres', "SELECT '123456789ABCDEF'");
> 
> Would it be simpler (and cheaper) to use SET instead of reloading the
> config? For example:
> 
> ---------------------------
> my $log_offset = -s $node->logfile;
> $node->psql(
>         'postgres', "
> SET log_statement_max_length TO 20;
> SELECT '123456789ABCDEF';
> ");
> ---------------------------


Done.
It's indeed much simpler this way. I replaced all append + reload
postgresql.conf calls with SET.


> +char *
> +truncate_query_log(const char *query)
> 
> In elog.c, truncate_query_log() is currently placed between write_stderr() and
> vwrite_stderr(). Since those two functions are related, it might be better to
> move truncate_query_log() to a more appropriate location. Thoughts?


Agreed.
The function now lives between check_log_of_query() and
get_backend_type_for_log(), which have more semantic overlap :)


> I see the patch has been moved to CommitFest PG20-1. Once development for v20
> starts, I'd like to commit it.


Terrific. Thanks!

Best, Jim