From d924e0b993e76201a1670976860425ce73ecacf4 Mon Sep 17 00:00:00 2001
From: Sergei Golubchik <serg@mariadb.org>
Date: Sat, 12 Aug 2017 19:09:03 +0200
Subject: [PATCH] MDEV-13375 back_log ignored

doing SYSVAR_AUTOSIZE() because of back_log > max_connections
enabled "autosized" flag, and that made IS_SYSVAR_AUTOSIZE()
true, which triggered the second SYSVAR_AUTOSIZE.

Remove back_log <= max_connections limit, back_log
doesn't *always* have to be smaller than max_connections.
---
 .../suite/sys_vars/r/back_log_basic.result    | 20 +------------------
 .../suite/sys_vars/t/back_log_basic.opt       |  1 +
 .../suite/sys_vars/t/back_log_basic.test      | 15 --------------
 sql/mysqld.cc                                 |  2 --
 4 files changed, 2 insertions(+), 36 deletions(-)
 create mode 100644 mysql-test/suite/sys_vars/t/back_log_basic.opt

diff --git a/mysql-test/suite/sys_vars/r/back_log_basic.result b/mysql-test/suite/sys_vars/r/back_log_basic.result
index 0940ebeef8c..df5eb6d977f 100644
--- a/mysql-test/suite/sys_vars/r/back_log_basic.result
+++ b/mysql-test/suite/sys_vars/r/back_log_basic.result
@@ -1,21 +1,3 @@
 select @@global.back_log;
 @@global.back_log
-80
-select @@session.back_log;
-ERROR HY000: Variable 'back_log' is a GLOBAL variable
-show global variables like 'back_log';
-Variable_name	Value
-back_log	80
-show session variables like 'back_log';
-Variable_name	Value
-back_log	80
-select * from information_schema.global_variables where variable_name='back_log';
-VARIABLE_NAME	VARIABLE_VALUE
-BACK_LOG	80
-select * from information_schema.session_variables where variable_name='back_log';
-VARIABLE_NAME	VARIABLE_VALUE
-BACK_LOG	80
-set global back_log=1;
-ERROR HY000: Variable 'back_log' is a read only variable
-set session back_log=1;
-ERROR HY000: Variable 'back_log' is a read only variable
+1000
diff --git a/mysql-test/suite/sys_vars/t/back_log_basic.opt b/mysql-test/suite/sys_vars/t/back_log_basic.opt
new file mode 100644
index 00000000000..fefc0d536b5
--- /dev/null
+++ b/mysql-test/suite/sys_vars/t/back_log_basic.opt
@@ -0,0 +1 @@
+--back-log=1000 --max-connections=300
diff --git a/mysql-test/suite/sys_vars/t/back_log_basic.test b/mysql-test/suite/sys_vars/t/back_log_basic.test
index 518ca2f0e5f..94a86416e49 100644
--- a/mysql-test/suite/sys_vars/t/back_log_basic.test
+++ b/mysql-test/suite/sys_vars/t/back_log_basic.test
@@ -2,18 +2,3 @@
 # show the global and session values;
 #
 select @@global.back_log;
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-select @@session.back_log;
-show global variables like 'back_log';
-show session variables like 'back_log';
-select * from information_schema.global_variables where variable_name='back_log';
-select * from information_schema.session_variables where variable_name='back_log';
-
-#
-# show that it's read-only
-#
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-set global back_log=1;
---error ER_INCORRECT_GLOBAL_LOCAL_VAR
-set session back_log=1;
-
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 64b6384ca5b..79e205219e1 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -9674,8 +9674,6 @@ static int get_options(int *argc_ptr, char ***argv_ptr)
 #endif
 
   /* Ensure that some variables are not set higher than needed */
-  if (back_log > max_connections)
-    SYSVAR_AUTOSIZE(back_log, max_connections);
   if (thread_cache_size > max_connections)
     SYSVAR_AUTOSIZE(thread_cache_size, max_connections);