BUG#30573: Ordered range scan over partitioned tables returns some rows twice

The problem: ha_partition::read_range_first() could return a record that is 
outside of the scanned range. If that record happened to be in the next 
subsequent range, it would satisfy the WHERE and appear in the output twice.
(we would get it the second time when scanning the next subsequent range)

Fix: 
Made ha_partition::read_range_first() check if the returned recod is within
the scanned range, like other read_range_first() implementations do.


mysql-test/r/partition_range.result:
  BUG#30573: Ordered range scan over partitioned tables returns some rows twice
   - Testcase
mysql-test/t/partition_range.test:
  BUG#30573: Ordered range scan over partitioned tables returns some rows twice
   - Testcase
sql/ha_partition.cc:
  BUG#30573: Ordered range scan over partitioned tables returns some rows twice
  - Make ha_partition::read_range_first() check if the returned record is 
    within the range.

1 files changed, 27 insertions, 1 deletions

diff --git a/mysql-test/t/partition_range.test b/mysql-test/t/partition_range.test
index 50d850913bc..a9f6d410fa3 100644
--- a/mysql-test/t/partition_range.test
+++ b/mysql-test/t/partition_range.test
@@ -6,7 +6,7 @@
 -- source include/have_partition.inc
 
 --disable_warnings
-drop table if exists t1;
+drop table if exists t1, t2;
 --enable_warnings
 
 #
@@ -757,3 +757,29 @@ DROP TABLE t1;
 #                       a = "C2345678901234567890";
 #select * from t1 where a = "12345678901234567890";
 #drop table t1;
+
+
+#
+# BUG#30573: get wrong result with "group by" on PARTITIONed table
+#
+create table t1 (a int);
+insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+CREATE TABLE t2 (
+  defid int(10) unsigned NOT NULL,
+  day int(10) unsigned NOT NULL,
+  count int(10) unsigned NOT NULL,
+  filler char(200),
+  KEY (defid,day)
+) 
+PARTITION BY RANGE (day) (
+  PARTITION p7 VALUES LESS THAN (20070401) , 
+  PARTITION p8 VALUES LESS THAN (20070501));
+
+insert into t2 select 20, 20070311, 1, 'filler' from t1 A, t1 B;
+insert into t2 select 20, 20070411, 1, 'filler' from t1 A, t1 B;
+insert into t2 values(52, 20070321, 123, 'filler') ;
+insert into t2 values(52, 20070322, 456, 'filler') ;
+
+select sum(count) from t2 ch where ch.defid in (50,52) and ch.day between 20070320 and 20070401 group by defid;
+drop table t1, t2;
+