Bug#19978: INSERT .. ON DUPLICATE erroneously reports some records were

updated.

INSERT ... ON DUPLICATE KEY UPDATE reports that a record was updated when
the duplicate key occurs even if the record wasn't actually changed
because the update values are the same as those in the record.

Now the compare_record() function is used to check whether the record was
changed and the update of a record reported only if the record differs
from the original one.


sql/sql_update.cc:
  Bug#19978: INSERT .. ON DUPLICATE erroneously reports some records were
  updated.
  The compare_record() function was changed to non-static one.
sql/sql_insert.cc:
  Bug#19978: INSERT .. ON DUPLICATE erroneously reports some records were
  updated.
  Now the compare_record() function is used to check whether the record was
  changed and the update of a record reported only if the record differs
  from the original one.
sql/mysql_priv.h:
  Bug#19978: INSERT .. ON DUPLICATE erroneously reports some records were
  updated.
  Added the prototype of the compare_record() function.
mysql-test/t/insert_select.test:
  Added a test case for bug#19978: INSERT .. ON DUPLICATE erroneously reports
  some records were updated.
mysql-test/r/insert_select.result:
  Added a test case for bug#19978: INSERT .. ON DUPLICATE erroneously reports
  some records were updated.

1 files changed, 12 insertions, 0 deletions

diff --git a/mysql-test/r/insert_select.result b/mysql-test/r/insert_select.result
index 1453d25ac75..82cc1b036a7 100644
--- a/mysql-test/r/insert_select.result
+++ b/mysql-test/r/insert_select.result
@@ -705,3 +705,15 @@ use bug21774_1;
 INSERT INTO bug21774_2.t1 SELECT t1.* FROM t1;
 DROP DATABASE bug21774_1;
 DROP DATABASE bug21774_2;
+USE test;
+create table t1(f1 int primary key, f2 int);
+insert into t1 values (1,1);
+affected rows: 1
+insert into t1 values (1,1) on duplicate key update f2=1;
+affected rows: 0
+insert into t1 values (1,1) on duplicate key update f2=2;
+affected rows: 2
+select * from t1;
+f1	f2
+1	2
+drop table t1;