Bug#27033: 0 as LAST_INSERT_ID() after INSERT .. ON DUPLICATE if rows were

touched but not actually changed.

The LAST_INSERT_ID() is reset to 0 if no rows were inserted or changed.
This is the case when an INSERT ... ON DUPLICATE KEY UPDATE updates a row
with the same values as the row contains.

Now the LAST_INSERT_ID() values is reset to 0 only if there were no rows
successfully inserted or touched.
The new 'touched' field is added to the COPY_INFO structure. It holds the
number of rows that were touched no matter whether they were actually
changed or not.


sql/sql_class.h:
  Bug#27033: 0 as LAST_INSERT_ID() after INSERT .. ON DUPLICATE if rows were
  touched but not actually changed.
  
  The new 'touched' field is added to the COPY_INFO structure. It holds the
  number of rows that were touched no matter whether they were actually
  changed or not.
mysql-test/r/insert_update.result:
  Added a test case for the bug#27033: 0 as LAST_INSERT_ID() after INSERT .. ON DUPLICATE if rows were
  touched but not actually changed.
mysql-test/t/insert_update.test:
  Added a test case for the bug#27033: 0 as LAST_INSERT_ID() after INSERT .. ON DUPLICATE if rows were
  touched but not actually changed.
sql/sql_insert.cc:
  Bug#27033: 0 as LAST_INSERT_ID() after INSERT .. ON DUPLICATE if rows were
  touched but not actually changed.
  
  Now the LAST_INSERT_ID() values is reset to 0 only if there were no rows
  successfully inserted or touched.

1 files changed, 17 insertions, 5 deletions

diff --git a/sql/sql_class.h b/sql/sql_class.h
index 995b5ac0bde..99803802001 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -356,13 +356,25 @@ public:
   inline uint32 get_open_count() { return open_count; }
 };
 
-
+/*
+  The COPY_INFO structure is used by INSERT/REPLACE code.
+  The schema of the row counting by the INSERT/INSERT ... ON DUPLICATE KEY
+  UPDATE code:
+    If a row is inserted then the copied variable is incremented.
+    If a row is updated by the INSERT ... ON DUPLICATE KEY UPDATE and the
+      new data differs from the old one then the copied and the updated
+      variables are incremented.
+    The touched variable is incremented if a row was touched by the update part
+      of the INSERT ... ON DUPLICATE KEY UPDATE no matter whether the row
+      was actually changed or not.
+*/
 typedef struct st_copy_info {
-  ha_rows records;
-  ha_rows deleted;
-  ha_rows updated;
-  ha_rows copied;
+  ha_rows records; /* Number of processed records */
+  ha_rows deleted; /* Number of deleted records */
+  ha_rows updated; /* Number of updated records */
+  ha_rows copied;  /* Number of copied records */
   ha_rows error_count;
+  ha_rows touched; /* Number of touched records */
   enum enum_duplicates handle_duplicates;
   int escape_char, last_errno;
   bool ignore;