5.6.17

storage/perfschema/table_threads.cc

@@ -1,4 +1,4 @@
-/* Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved.
+/* Copyright (c) 2008, 2014, Oracle and/or its affiliates. All rights reserved.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -129,7 +129,9 @@ table_threads::table_threads()
 void table_threads::make_row(PFS_thread *pfs)
 {
   pfs_lock lock;
-  pfs_lock processlist_lock;
+  pfs_lock session_lock;
+  pfs_lock stmt_lock;
+  PFS_stage_class *stage_class;
   PFS_thread_class *safe_class;
 
   m_row_exists= false;
@@ -147,6 +149,9 @@ void table_threads::make_row(PFS_thread *pfs)
   m_row.m_name= safe_class->m_name;
   m_row.m_name_length= safe_class->m_name_length;
 
+  /* Protect this reader against session attribute changes */
+  pfs->m_session_lock.begin_optimistic_lock(&session_lock);
+
   m_row.m_username_length= pfs->m_username_length;
   if (unlikely(m_row.m_username_length > sizeof(m_row.m_username)))
     return;
@@ -159,38 +164,66 @@ void table_threads::make_row(PFS_thread *pfs)
   if (m_row.m_hostname_length != 0)
     memcpy(m_row.m_hostname, pfs->m_hostname, m_row.m_hostname_length);
 
+  if (! pfs->m_session_lock.end_optimistic_lock(& session_lock))
+  {
+    /*
+      One of the columns:
+      - PROCESSLIST_USER
+      - PROCESSLIST_HOST
+      is being updated.
+      Do not discard the entire row.
+      Do not loop waiting for a stable value.
+      Just return NULL values.
+    */
+    m_row.m_username_length= 0;
+    m_row.m_hostname_length= 0;
+  }
+
+  /* Protect this reader against statement attributes changes */
+  pfs->m_stmt_lock.begin_optimistic_lock(&stmt_lock);
+
   m_row.m_dbname_length= pfs->m_dbname_length;
   if (unlikely(m_row.m_dbname_length > sizeof(m_row.m_dbname)))
     return;
   if (m_row.m_dbname_length != 0)
     memcpy(m_row.m_dbname, pfs->m_dbname, m_row.m_dbname_length);
 
-  m_row.m_command= pfs->m_command;
-  m_row.m_start_time= pfs->m_start_time;
-
-  /* Protect this reader against attribute changes. */
-  pfs->m_processlist_lock.begin_optimistic_lock(&processlist_lock);
-
-  /* FIXME: need to copy it ? */
-  m_row.m_processlist_state_ptr= pfs->m_processlist_state_ptr;
-  m_row.m_processlist_state_length= pfs->m_processlist_state_length;
-  /* FIXME: need to copy it ? */
-  m_row.m_processlist_info_ptr= pfs->m_processlist_info_ptr;
+  m_row.m_processlist_info_ptr= & pfs->m_processlist_info[0];
   m_row.m_processlist_info_length= pfs->m_processlist_info_length;
 
-  if (! pfs->m_processlist_lock.end_optimistic_lock(& processlist_lock))
+  if (! pfs->m_stmt_lock.end_optimistic_lock(& stmt_lock))
   {
     /*
-      Columns PROCESSLIST_STATE or PROCESSLIST_INFO are being
-      updated while we read them, and are unsafe to use.
+      One of the columns:
+      - PROCESSLIST_DB
+      - PROCESSLIST_INFO
+      is being updated.
       Do not discard the entire row.
       Do not loop waiting for a stable value.
-      Just return NULL values for these columns.
+      Just return NULL values.
     */
-    m_row.m_processlist_state_length= 0;
+    m_row.m_dbname_length= 0;
     m_row.m_processlist_info_length= 0;
   }
 
+  /* Dirty read, sanitize the command. */
+  m_row.m_command= pfs->m_command;
+  if ((m_row.m_command < 0) || (m_row.m_command > COM_END))
+    m_row.m_command= COM_END;
+
+  m_row.m_start_time= pfs->m_start_time;
+
+  stage_class= find_stage_class(pfs->m_stage);
+  if (stage_class != NULL)
+  {
+    m_row.m_processlist_state_ptr= stage_class->m_name + stage_class->m_prefix_length;
+    m_row.m_processlist_state_length= stage_class->m_name_length - stage_class->m_prefix_length;
+  }
+  else
+  {
+    m_row.m_processlist_state_length= 0;
+  }
+
   m_row.m_enabled_ptr= &pfs->m_enabled;
 
   if (pfs->m_lock.end_optimistic_lock(& lock))
@@ -276,8 +309,22 @@ int table_threads::read_row_values(TABLE *table,
         break;
       case 9: /* PROCESSLIST_STATE */
         if (m_row.m_processlist_state_length > 0)
+        {
+          /* This column's datatype is declared as varchar(64). But in current
+             code, there are few process state messages which are greater than
+             64 characters(Eg:stage_slave_has_read_all_relay_log).
+             In those cases, we will end up in 'data truncated'
+             warning/error (depends sql_mode setting) when server is updating
+             this column for those threads. Since 5.6 is GAed, neither the
+             metadata of this column can be changed, nor those state messages.
+             So server will silently truncate the state message to 64 characters
+             if it is longer. In Upper versions(5.7+), these state messages are
+             changed to less than or equal to 64 characters.
+           */
           set_field_varchar_utf8(f, m_row.m_processlist_state_ptr,
-                                 m_row.m_processlist_state_length);
+                                 std::min<uint>(m_row.m_processlist_state_length,
+                                                f->char_length()));
+        }
         else
           f->set_null();
         break;