Bug#20559828 SHOW GLOBAL VARIABLES WHERE NOT DEPRECATED IN EMBEDDED

Before this fix, the command:
  SHOW GLOBAL VARIABLE WHERE ...
printed a deprecation warning, inviting to use the performance_schema tables
instead.

This warning was incorrect, and caused confusion for the embedded build.

There are two separate changes that are independent:

First, the syntax
  SHOW GLOBAL VARIABLE WHERE ... [LIKE ...]
should be changed to simply
  SHOW GLOBAL VARIABLE [like ...]
abandonning the WHERE clause syntax.
This applies to all builds, including embedded.

Secondly, the query
  SHOW GLOBAL VARIABLE [like ...]
might be rewritten using the new performance_schema tables instead.
This is optional, and only applies to builds that include the
performance_schema (hence does not apply for the embedded build).

The warning printed mixed the two changes.

The deprecation only applies to the first part,
dropping support for the WHERE clause in SHOW STATUS / SHOW VARIABLES.

With this fix, the proper deprecation warning is now printed,
and it is also printed for embedded builds.

(cherry picked from commit 7323b2abfb98105f76336b81d1e010a0c0036c45)

Author: marcalff

mysql-test/r/show_variables.result

@@ -0,0 +1,18 @@
+SHOW GLOBAL VARIABLES WHERE Variable_name LIKE "abc";
+Variable_name	Value
+Warnings:
+Warning	1287	'SHOW GLOBAL VARIABLES WHERE' is deprecated and will be removed in a future release. Please use SHOW GLOBAL VARIABLES [LIKE] instead
+SHOW GLOBAL VARIABLES LIKE "abc";
+Variable_name	Value
+SHOW SESSION VARIABLES WHERE Variable_name LIKE "abc";
+Variable_name	Value
+Warnings:
+Warning	1287	'SHOW SESSION VARIABLES WHERE' is deprecated and will be removed in a future release. Please use SHOW SESSION VARIABLES [LIKE] instead
+SHOW SESSION VARIABLES LIKE "abc";
+Variable_name	Value
+SHOW VARIABLES WHERE Variable_name LIKE "abc";
+Variable_name	Value
+Warnings:
+Warning	1287	'SHOW SESSION VARIABLES WHERE' is deprecated and will be removed in a future release. Please use SHOW SESSION VARIABLES [LIKE] instead
+SHOW VARIABLES LIKE "abc";
+Variable_name	Value

mysql-test/suite/perfschema/r/show_coverage.result

@@ -11,22 +11,22 @@ set global show_compatibility_56 = ON;
 SHOW GLOBAL STATUS WHERE VARIABLE_NAME LIKE "foo";
 Variable_name	Value
 Warnings:
-Warning	1287	'SHOW GLOBAL STATUS WHERE' is deprecated and will be removed in a future release. Please use performance_schema.global_status instead
+Warning	1287	'SHOW GLOBAL STATUS WHERE' is deprecated and will be removed in a future release. Please use SHOW GLOBAL STATUS [LIKE] instead
 
 SHOW SESSION STATUS WHERE VARIABLE_NAME LIKE "foo";
 Variable_name	Value
 Warnings:
-Warning	1287	'SHOW SESSION STATUS WHERE' is deprecated and will be removed in a future release. Please use performance_schema.session_status instead
+Warning	1287	'SHOW SESSION STATUS WHERE' is deprecated and will be removed in a future release. Please use SHOW SESSION STATUS [LIKE] instead
 
 SHOW GLOBAL VARIABLES WHERE VARIABLE_NAME LIKE "foo";
 Variable_name	Value
 Warnings:
-Warning	1287	'SHOW GLOBAL VARIABLES WHERE' is deprecated and will be removed in a future release. Please use performance_schema.global_variables instead
+Warning	1287	'SHOW GLOBAL VARIABLES WHERE' is deprecated and will be removed in a future release. Please use SHOW GLOBAL VARIABLES [LIKE] instead
 
 SHOW SESSION VARIABLES WHERE VARIABLE_NAME LIKE "foo";
 Variable_name	Value
 Warnings:
-Warning	1287	'SHOW SESSION VARIABLES WHERE' is deprecated and will be removed in a future release. Please use performance_schema.session_variables instead
+Warning	1287	'SHOW SESSION VARIABLES WHERE' is deprecated and will be removed in a future release. Please use SHOW SESSION VARIABLES [LIKE] instead
 
 # TEST 2
 # CREATE..SELECT -- Expect correct ERR_WARN_DEPRECATED_SYNTAX

mysql-test/t/show_variables.test

@@ -0,0 +1,19 @@
+
+# Deprecation warning
+SHOW GLOBAL VARIABLES WHERE Variable_name LIKE "abc";
+
+# No warnings
+SHOW GLOBAL VARIABLES LIKE "abc";
+
+# Deprecation warning
+SHOW SESSION VARIABLES WHERE Variable_name LIKE "abc";
+
+# No warnings
+SHOW SESSION VARIABLES LIKE "abc";
+
+# Deprecation warning
+SHOW VARIABLES WHERE Variable_name LIKE "abc";
+
+# No warnings
+SHOW VARIABLES LIKE "abc";
+

sql/sql_show.cc

@@ -6918,12 +6918,12 @@ void push_show_where_warning(THD *thd, enum enum_var_type option_type, bool stat
   if (option_type == OPT_GLOBAL)
   {
     old_name= (status ? "SHOW GLOBAL STATUS WHERE" : "SHOW GLOBAL VARIABLES WHERE");
-    new_name= (status ? "performance_schema.global_status" : "performance_schema.global_variables");
+    new_name= (status ? "SHOW GLOBAL STATUS [LIKE]" : "SHOW GLOBAL VARIABLES [LIKE]");
   }
   else
   {
     old_name= (status ? "SHOW SESSION STATUS WHERE" : "SHOW SESSION VARIABLES WHERE");
-    new_name= (status ? "performance_schema.session_status" : "performance_schema.session_variables");
+    new_name= (status ? "SHOW SESSION STATUS [LIKE]" : "SHOW SESSION VARIABLES [LIKE]");
   }
 
   push_warning_printf(thd, Sql_condition::SL_WARNING,
@@ -6960,7 +6960,6 @@ int fill_variables(THD *thd, TABLE_LIST *tables, Item *cond)
     option_type= OPT_SESSION;
   }
 
-#ifndef EMBEDDED_LIBRARY
   /* Issue deprecation warning. */
   if (lex->sql_command == SQLCOM_SHOW_VARIABLES)
   {
@@ -6969,6 +6968,7 @@ int fill_variables(THD *thd, TABLE_LIST *tables, Item *cond)
       push_show_where_warning(thd, option_type, false);
     }
   }
+#ifndef EMBEDDED_LIBRARY
   else
   {
     push_select_warning(thd, option_type, false);
@@ -7028,7 +7028,6 @@ int fill_status(THD *thd, TABLE_LIST *tables, Item *cond)
     tmp1= &thd->status_var;
   }
 
-#ifndef EMBEDDED_LIBRARY
   /* Issue deprecation warning. */
   if (lex->sql_command == SQLCOM_SHOW_STATUS)
   {
@@ -7037,6 +7036,7 @@ int fill_status(THD *thd, TABLE_LIST *tables, Item *cond)
       push_show_where_warning(thd, option_type, true);
     }
   }
+#ifndef EMBEDDED_LIBRARY
   else
   {
     push_select_warning(thd, option_type, true);