Fix for BUG#4177:

 * Make index merge quick selects code allow perform several scans.
 * Delay additional handler objects creation till row retrieval is started.


include/queues.h:
  Added trivial queue_remove_all macro
mysql-test/r/index_merge.result:
  Testcase for BUG#4177
mysql-test/t/index_merge.test:
  Testcase for BUG#4177
sql/opt_range.cc:
  Fix for BUG#4177: 
   * For any quick select, row retrieval can be performed several times. Now all index_merge quick selects code handles such cases properly.
   * In QUICK_INDEX_MERGE_SELECT we use one handler object for all merged scans, and it was possible that in 
      destructor several cleanup functions were called 
   * Additionally
    - Removed redundant QUICK_INDEX_MERGE_SELECT members.
    - Now QUICK_ROR_*_SELECTs create additional handler objects only when row retrieval is started
      So if join optimizer chooses other access method, we don't create/delete handlers.

1 files changed, 46 insertions, 3 deletions

diff --git a/mysql-test/t/index_merge.test b/mysql-test/t/index_merge.test
index a4f7b71e5a3..3ab68d85125 100644
--- a/mysql-test/t/index_merge.test
+++ b/mysql-test/t/index_merge.test
@@ -1,9 +1,8 @@
 #
 # Index merge tests
 #
-
 --disable_warnings
-drop table if exists t0, t1, t2, t3,t4;
+drop table if exists t0, t1, t2, t3, t4;
 --enable_warnings
 
 # Create and fill a table with simple keys
@@ -278,4 +277,48 @@ delete from t0 where key1 < 3 or key2 < 4;
 select * from t0 where key1 < 3 or key2 < 4;
 select count(*) from t0;
 
-drop table t0, t1, t2, t3, t4; 
+# Test for BUG#4177
+drop table t4;
+create table t4 (a int);
+insert into t4 values (1),(4),(3);
+set @save_join_buffer_size=@@join_buffer_size;
+set join_buffer_size= 4000;
+show variables like 'join_buffer_size';
+explain select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5) 
+ from t0 as A force index(i1,i2), t0 as B force index (i1,i2) 
+  where (A.key1 < 500000 or A.key2 < 3)
+  and   (B.key1 < 500000 or B.key2 < 3);
+
+select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5) 
+ from t0 as A force index(i1,i2), t0 as B force index (i1,i2) 
+  where (A.key1 < 500000 or A.key2 < 3)
+  and   (B.key1 < 500000 or B.key2 < 3);
+
+update t0 set key1=1;
+explain select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5) 
+ from t0 as A force index(i1,i2), t0 as B force index (i1,i2) 
+  where (A.key1 = 1 or A.key2 = 1)
+  and   (B.key1 = 1 or B.key2 = 1);
+
+select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5) 
+ from t0 as A force index(i1,i2), t0 as B force index (i1,i2) 
+  where (A.key1 = 1 or A.key2 = 1)
+  and   (B.key1 = 1 or B.key2 = 1);
+
+alter table t0 add filler1 char(200), add filler2 char(200), add filler3 char(200);
+update t0 set key2=1, key3=1, key4=1, key5=1,key6=1,key7=1 where key7 < 500;
+explain select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5) 
+ from t0 as A, t0 as B 
+ where (A.key1 = 1 and A.key2 = 1 and A.key3 = 1 and A.key4=1 and A.key5=1 and A.key6=1 and A.key7 = 1 or A.key8=1)
+  and (B.key1 = 1 and B.key2 = 1 and B.key3 = 1 and B.key4=1 and B.key5=1 and B.key6=1 and B.key7 = 1 or B.key8=1);
+
+select max(A.key1 + B.key1 + A.key2 + B.key2 + A.key3 + B.key3 + A.key4 + B.key4 + A.key5 + B.key5) 
+ from t0 as A, t0 as B 
+ where (A.key1 = 1 and A.key2 = 1 and A.key3 = 1 and A.key4=1 and A.key5=1 and A.key6=1 and A.key7 = 1 or A.key8=1)
+  and (B.key1 = 1 and B.key2 = 1 and B.key3 = 1 and B.key4=1 and B.key5=1 and B.key6=1 and B.key7 = 1 or B.key8=1);
+
+set join_buffer_size= @save_join_buffer_size;
+# Test for BUG#4177 ends 
+
+drop table t0, t1, t2, t3, t4;
+