Bug#31410674: RESTORE SET PERSISTED LOG_ERROR_VERBOSITY IN TIME TO AFFECT INNODB SET-UP

During start-up, the order is roughly,
- read .cnf files
- read SET PERSISTed system variables
- restore "read-only_ persists by appending
  them to the command-line
- parse "early" command-line options
  (handle_early_options())
- init many things (incl. error log)
- parse "regular" command-line options (get_options())
- init server components
  (open error log, init InnoDB, init DD, read auto.cnf, ...)
- component infrastructure
  (as dependent on InnoDB for its config)
- restore "regular" PERSISTs by emulating SET GLOBAL ...
- engage loadable logging components
...

This means that if setting log_error_verbosity on
the command-line, the new value will be set and
become active before InnoDB starts.

However if log_error_verbosity is PERSISTed,
it is restored as a "regular_ persisted sys-var,
and therefore only after InnoDB has started.
As a result, its value will not be used to filter
InnoDB's start-up messages.

Fix:
Tagging the sys-var, log_error_verbosity,
as PERSIST_AS_READONLY results in the
persisted value being restored via the
command-line.

This way,

a) the value will be set before InnoDB
starts up, so InnoDB's messages will be
filtered using the desired verbosity;

b) the log_error_verbosity's behaviour
when using SET PERSIST is more in line
with its behaviour when setting the
value from the command-line.

Patch flags log_error_suppression_list
in the same way. As it is an option
for filtering error-log messages that
affects the same filter (log_filter_internal),
it should be applied at the same time to
avoid surprises.

Approved by: Jens Even Blomsoy <[email protected]>

Author: Tatiana Azundris Nuernberg

sql/sys_vars.cc

@@ -2466,9 +2466,9 @@ static Sys_var_charptr Sys_log_error_suppression_list(
     "or Error severity will always be included. Requires the filter "
     "\'log_filter_internal\' to be set in @@global.log_error_services, which "
     "is the default.",
-    GLOBAL_VAR(opt_log_error_suppression_list), CMD_LINE(REQUIRED_ARG),
-    IN_SYSTEM_CHARSET, DEFAULT(""), NO_MUTEX_GUARD, NOT_IN_BINLOG,
-    ON_CHECK(check_log_error_suppression_list),
+    PERSIST_AS_READONLY GLOBAL_VAR(opt_log_error_suppression_list),
+    CMD_LINE(REQUIRED_ARG), IN_SYSTEM_CHARSET, DEFAULT(""), NO_MUTEX_GUARD,
+    NOT_IN_BINLOG, ON_CHECK(check_log_error_suppression_list),
     ON_UPDATE(fix_log_error_suppression_list));
 
 static Sys_var_bool Sys_log_queries_not_using_indexes(
@@ -2523,9 +2523,9 @@ static Sys_var_ulong Sys_log_error_verbosity(
     "2, log errors and warnings. "
     "3, log errors, warnings, and notes. "
     "Messages sent to the client are unaffected by this setting.",
-    GLOBAL_VAR(log_error_verbosity), CMD_LINE(REQUIRED_ARG), VALID_RANGE(1, 3),
-    DEFAULT(2), BLOCK_SIZE(1), NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(nullptr),
-    ON_UPDATE(update_log_error_verbosity));
+    PERSIST_AS_READONLY GLOBAL_VAR(log_error_verbosity), CMD_LINE(REQUIRED_ARG),
+    VALID_RANGE(1, 3), DEFAULT(2), BLOCK_SIZE(1), NO_MUTEX_GUARD, NOT_IN_BINLOG,
+    ON_CHECK(nullptr), ON_UPDATE(update_log_error_verbosity));
 
 static Sys_var_enum Sys_log_timestamps(
     "log_timestamps",