Re: Truncate logs by max_log_size

On 28.11.24 20:20, Kirill Gavrilov wrote:
>   Here is version 3 of this patch. I found another place where this
> setting can be applied. 
>   Also added some documentation and specified that this setting
> truncates queries by size in bytes.

Thanks. It is now possible to change the parameter using SET

postgres=# SET max_log_size TO 15;
SET
postgres=# SHOW max_log_size ;
 max_log_size
--------------
 15
(1 row)

In the postgresql.conf the default value is set to 0

#max_log_size = 0

But if we take a look at the parameter it shows something else

postgres=# SHOW max_log_size ;
 max_log_size
--------------
 5242880
(1 row)

Perhaps it would be best to keep the default value in the
postgresql.conf consistent with the documentation and the actual
max_log_size value. IMHO 0 (or -1) should disable it.

There are also several compilation issues:

postgres.c: In function ‘exec_simple_query’:
postgres.c:1040:9: warning: ISO C90 forbids mixed declarations and code
[-Wdeclaration-after-statement]
 1040 |         bool copied = false;
      |         ^~~~
elog.c: In function ‘EmitErrorReport’:
elog.c:1697:9: warning: ISO C90 forbids mixed declarations and code
[-Wdeclaration-after-statement]
 1697 |         const char* old_query_string = debug_query_string;
      |         ^~~~~
elog.c:1744:23: warning: passing argument 1 of ‘pfree’ discards ‘const’
qualifier from pointer target type [-Wdiscarded-qualifiers]
 1744 |                 pfree(debug_query_string);
      |                       ^~~~~~~~~~~~~~~~~~
In file included from ../../../../src/include/postgres.h:47,
                 from elog.c:55:
../../../../src/include/utils/palloc.h:86:25: note: expected ‘void *’
but argument is of type ‘const char *’
   86 | extern void pfree(void *pointer);
      |                   ~~~~~~^~~~~~~
elog.c: In function ‘build_query_log’:
elog.c:3798:9: warning: ISO C90 forbids mixed declarations and code
[-Wdeclaration-after-statement]
 3798 |         size_t query_len = strlen(query);
      |         ^~~~~~
elog.c:3801:24: warning: return discards ‘const’ qualifier from pointer
target type [-Wdiscarded-qualifiers]
 3801 |                 return query;
      |                        ^~~~~
elog.c:3805:9: warning: ISO C90 forbids mixed declarations and code
[-Wdeclaration-after-statement]
 3805 |         size_t query_log_len = pg_mbcliplen(query, query_len,
max_log_size);
      |         ^~~~~~

and there is a trailing whitespace at:

+ *    If query needs to be truncated, copied will be set to true

/home/jim/patches/max_log_query/V3-0001-parameter-max_log_size-to-truncate-logs.patch:141:
trailing whitespace.
 *      If query needs to be truncated, copied will be set to true
Checking patch doc/src/sgml/config.sgml...
Hunk #1 succeeded at 7865 (offset -48 lines).
Checking patch src/backend/tcop/postgres.c...
Hunk #1 succeeded at 71 (offset 1 line).
Hunk #2 succeeded at 1031 (offset 1 line).
Hunk #3 succeeded at 1083 (offset 1 line).
Hunk #4 succeeded at 1382 (offset 1 line).
Hunk #5 succeeded at 1393 (offset 1 line).
Checking patch src/backend/utils/error/elog.c...
Hunk #4 succeeded at 3781 (offset -3 lines).
Checking patch src/backend/utils/misc/guc_tables.c...
Hunk #1 succeeded at 3714 (offset -10 lines).
Checking patch src/backend/utils/misc/postgresql.conf.sample...
Hunk #1 succeeded at 615 (offset -2 lines).
Checking patch src/bin/pg_ctl/t/004_logrotate.pl...
Checking patch src/include/utils/elog.h...
Applied patch doc/src/sgml/config.sgml cleanly.
Applied patch src/backend/tcop/postgres.c cleanly.
Applied patch src/backend/utils/error/elog.c cleanly.
Applied patch src/backend/utils/misc/guc_tables.c cleanly.
Applied patch src/backend/utils/misc/postgresql.conf.sample cleanly.
Applied patch src/bin/pg_ctl/t/004_logrotate.pl cleanly.
Applied patch src/include/utils/elog.h cleanly.
warning: 1 line adds whitespace errors.

--
Jim