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.

2 files changed, 25 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;
diff --git a/mysql-test/t/insert_select.test b/mysql-test/t/insert_select.test
index 404d67390ab..6302d5f1dae 100644
--- a/mysql-test/t/insert_select.test
+++ b/mysql-test/t/insert_select.test
@@ -265,4 +265,17 @@ INSERT INTO bug21774_2.t1 SELECT t1.* FROM t1;
 
 DROP DATABASE bug21774_1;
 DROP DATABASE bug21774_2;
+USE test;
 
+#
+# Bug#19978: INSERT .. ON DUPLICATE erroneously reports some records were
+#            updated.
+#
+create table t1(f1 int primary key, f2 int);
+--enable_info
+insert into t1 values (1,1);
+insert into t1 values (1,1) on duplicate key update f2=1;
+insert into t1 values (1,1) on duplicate key update f2=2;
+--disable_info
+select * from t1;
+drop table t1;