Manual merge of mysql-5.1-bugteam to mysql-trunk-merge.

Conflicts:

   conflict      Makefile.am
   conflict      mysql-test/suite/rpl/r/rpl_stm_mixing_engines.result
   conflict      mysql-test/suite/rpl/t/rpl_tmp_table_and_DDL.test
   conflict      sql/opt_sum.cc
   conflict      sql/set_var.cc
   conflict      sql/sql_base.cc
   conflict      sql/sql_priv.h
   conflict      sql/sql_show.cc

1 files changed, 9 insertions, 2 deletions

diff --git a/sql/sql_class.h b/sql/sql_class.h
index 950ef83b237..a1a115cb53d 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -2051,8 +2051,15 @@ public:
   */
   ha_rows    sent_row_count;
 
-  /*
-    number of rows we read, sent or not, including in create_sort_index()
+  /**
+    Number of rows read and/or evaluated for a statement. Used for
+    slow log reporting.
+
+    An examined row is defined as a row that is read and/or evaluated
+    according to a statement condition, including in
+    create_sort_index(). Rows may be counted more than once, e.g., a
+    statement including ORDER BY could possibly evaluate the row in
+    filesort() before reading it for e.g. update.
   */
   ha_rows    examined_row_count;