mdev-224 plugin usage statistics in the feedback reports

mysql-test/suite/plugins/r/feedback_plugin_install.result

@@ -5,7 +5,8 @@ ACTIVE
 select * from information_schema.feedback where variable_name like 'feed%'
        and variable_name not like  '%_uid';
 VARIABLE_NAME	VARIABLE_VALUE
-FEEDBACK	1.1
+FEEDBACK used	1
+FEEDBACK version	1.1
 FEEDBACK_SEND_RETRY_WAIT	60
 FEEDBACK_SEND_TIMEOUT	60
 FEEDBACK_URL	http://mariadb.org/feedback_plugin/post

mysql-test/suite/plugins/r/feedback_plugin_load.result

@@ -4,7 +4,8 @@ ACTIVE
 select * from information_schema.feedback where variable_name like 'feed%'
        and variable_name not like  '%_uid';
 VARIABLE_NAME	VARIABLE_VALUE
-FEEDBACK	1.1
+FEEDBACK used	1
+FEEDBACK version	1.1
 FEEDBACK_SEND_RETRY_WAIT	60
 FEEDBACK_SEND_TIMEOUT	60
 FEEDBACK_URL	http://mariadb.org/feedback_plugin/post

mysql-test/suite/plugins/r/feedback_plugin_send.result

@@ -4,7 +4,8 @@ ACTIVE
 select * from information_schema.feedback where variable_name like 'feed%'
        and variable_name not like  '%_uid';
 VARIABLE_NAME	VARIABLE_VALUE
-FEEDBACK	1.1
+FEEDBACK used	2
+FEEDBACK version	1.1
 FEEDBACK_SEND_RETRY_WAIT	60
 FEEDBACK_SEND_TIMEOUT	60
 FEEDBACK_URL	http://mariadb.org/feedback_plugin/post

plugin/feedback/utils.cc

@@ -152,26 +152,36 @@ namespace feedback {
 static const bool UNSIGNED= true; ///< used below when inserting integers
 
 /**
-  callback for fill_plugin_version() - insert a plugin name and its version
+  callback for fill_plugins()
 */
 static my_bool show_plugins(THD *thd, plugin_ref plugin, void *arg)
 {
   TABLE *table= (TABLE*) arg;
+  char name[NAME_LEN*2];
+  size_t name_len;
   char version[20];
   size_t version_len;
 
+  name_len= my_snprintf(name, sizeof(name), "%s version",
+                        plugin_name(plugin)->str); 
+
   version_len= my_snprintf(version, sizeof(version), "%d.%d",
                            (plugin_decl(plugin)->version) >> 8,
                            (plugin_decl(plugin)->version) & 0xff);
 
-  INSERT2(plugin_name(plugin)->str, plugin_name(plugin)->length,
+  INSERT2(name, name_len,
           (version, version_len, system_charset_info));
 
+  name_len= my_snprintf(name, sizeof(name), "%s used",
+                        plugin_name(plugin)->str); 
+
+  INSERT2(name, name_len, (plugin_ref_to_int(plugin)->locks_total, UNSIGNED));
+
   return 0;
 }
 
 /**
-  inserts all plugins and their versions into I_S.FEEDBACK
+  inserts all plugins, their versions, and usage counters
 */
 int fill_plugin_version(THD *thd, TABLE_LIST *tables)
 {

sql/sql_plugin.cc

@@ -980,9 +980,13 @@ plugin_ref plugin_lock(THD *thd, plugin_ref ptr)
     without a mutex.
   */
   if (! plugin_dlib(ptr))
+  {
+    plugin_ref_to_int(ptr)->locks_total++;
     DBUG_RETURN(ptr);
+  }
 #endif
   mysql_mutex_lock(&LOCK_plugin);
+  plugin_ref_to_int(ptr)->locks_total++;
   rc= my_intern_plugin_lock_ci(lex, ptr);
   mysql_mutex_unlock(&LOCK_plugin);
   DBUG_RETURN(rc);

sql/sql_plugin.h

@@ -99,6 +99,7 @@ struct st_plugin_int
   struct st_plugin_dl *plugin_dl;
   uint state;
   uint ref_count;               /* number of threads using the plugin */
+  uint locks_total;             /* how many times the plugin was locked */
   void *data;                   /* plugin type specific, e.g. handlerton */
   MEM_ROOT mem_root;            /* memory for dynamic plugin structures */
   sys_var *system_vars;         /* server variables for this plugin */