bk commit into 5.1 tree (knielsen:1.2645) BUG#33061

[knielsen]

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ChangeSet@stripped, 2007-12-18 13:40:35+01:00, knielsen@ymer.(none) +5 -0
  Bug #33061: ORDER BY DESC becomes ASC in NDB partition pruning to one partition
  
  When partition pruning resulted in an ordered index scan spanning only
  one partition, any descending flag for the scan was wrongly discarded,
  turning ORDER BY DESC into ORDER BY ASC, and similar problems.
  
  Fixed by correctly passing descending flag in SCAN_TABREQ signal sent
  to data nodes.

  mysql-test/suite/ndb/r/ndb_partition_key.result@stripped, 2007-12-18 13:40:26+01:00,
knielsen@ymer.(none) +17 -0
    Test case.

  mysql-test/suite/ndb/r/ndb_partition_range.result@stripped, 2007-12-18 13:40:26+01:00,
knielsen@ymer.(none) +8 -0
    Test case.

  mysql-test/suite/ndb/t/ndb_partition_key.test@stripped, 2007-12-18 13:40:26+01:00,
knielsen@ymer.(none) +4 -0
    Test case.

  mysql-test/suite/ndb/t/ndb_partition_range.test@stripped, 2007-12-18 13:40:27+01:00,
knielsen@ymer.(none) +5 -0
    Test case.

  storage/ndb/src/ndbapi/NdbScanOperation.cpp@stripped, 2007-12-18 13:40:27+01:00,
knielsen@ymer.(none) +27 -15
    Even if ordered scan not requested (no need to merge-sorts scans of
    each partition), we still need to honor the descending flag.

diff -Nrup a/mysql-test/suite/ndb/r/ndb_partition_key.result
b/mysql-test/suite/ndb/r/ndb_partition_key.result
--- a/mysql-test/suite/ndb/r/ndb_partition_key.result	2007-06-27 14:27:31 +02:00
+++ b/mysql-test/suite/ndb/r/ndb_partition_key.result	2007-12-18 13:40:26 +01:00
@@ -38,6 +38,23 @@ a	b	c
 1	10	3
 1	11	3
 1	12	3
+select max(b) from t1 where a = 1;
+max(b)
+12
+select b from t1 where a = 1 order by b desc;
+b
+12
+11
+10
+9
+8
+7
+6
+5
+4
+3
+2
+1
 DROP TABLE t1;
 CREATE TABLE t1 (a INT, b CHAR(10) COLLATE latin1_bin, c INT, d INT,
 PRIMARY KEY (a,b,c) USING HASH)
diff -Nrup a/mysql-test/suite/ndb/r/ndb_partition_range.result
b/mysql-test/suite/ndb/r/ndb_partition_range.result
--- a/mysql-test/suite/ndb/r/ndb_partition_range.result	2007-06-27 14:27:24 +02:00
+++ b/mysql-test/suite/ndb/r/ndb_partition_range.result	2007-12-18 13:40:26 +01:00
@@ -46,6 +46,14 @@ a	b	c
 1	1	1
 6	1	1
 10	1	1
+INSERT into t1 values (1, 2, 2);
+select max(b) from t1 where a = 1;
+max(b)
+2
+select b from t1 where a = 1 order by b desc;
+b
+2
+1
 drop table t1;
 CREATE TABLE t1 (
 a int not null,
diff -Nrup a/mysql-test/suite/ndb/t/ndb_partition_key.test
b/mysql-test/suite/ndb/t/ndb_partition_key.test
--- a/mysql-test/suite/ndb/t/ndb_partition_key.test	2007-07-04 22:06:24 +02:00
+++ b/mysql-test/suite/ndb/t/ndb_partition_key.test	2007-12-18 13:40:26 +01:00
@@ -38,6 +38,10 @@ insert into t1 values 
 
 select * from t1 order by b;
 
+# BUG#33061: ORDER BY DESC becomes ASC in NDB partition pruning to one partition
+select max(b) from t1 where a = 1;
+select b from t1 where a = 1 order by b desc;
+
 DROP TABLE t1;
 
 #
diff -Nrup a/mysql-test/suite/ndb/t/ndb_partition_range.test
b/mysql-test/suite/ndb/t/ndb_partition_range.test
--- a/mysql-test/suite/ndb/t/ndb_partition_range.test	2007-07-04 22:06:24 +02:00
+++ b/mysql-test/suite/ndb/t/ndb_partition_range.test	2007-12-18 13:40:27 +01:00
@@ -48,6 +48,11 @@ select * from t1 where a=21 order by a;
 select * from t1 where a in (1,6,10,21) order by a;
 select * from t1 where b=1 and a in (1,6,10,21) order by a;
 
+# BUG#33061: ORDER BY DESC becomes ASC in NDB partition pruning to one partition
+INSERT into t1 values (1, 2, 2);
+select max(b) from t1 where a = 1;
+select b from t1 where a = 1 order by b desc;
+
 drop table t1;
 
 #
diff -Nrup a/storage/ndb/src/ndbapi/NdbScanOperation.cpp
b/storage/ndb/src/ndbapi/NdbScanOperation.cpp
--- a/storage/ndb/src/ndbapi/NdbScanOperation.cpp	2007-10-15 09:10:10 +02:00
+++ b/storage/ndb/src/ndbapi/NdbScanOperation.cpp	2007-12-18 13:40:27 +01:00
@@ -1340,29 +1340,41 @@ NdbIndexScanOperation::readTuples(LockMo
     if(insertATTRINFO(word) == -1)
       res = -1;
   }
-  if(!res && order_by){
-    m_ordered = true;
+  if (!res)
+  {
+    /**
+     * Note that it is valid to have order_desc true and order_by false.
+     *
+     * This means that there will be no merge sort among partitions, but
+     * each partition will still be returned in descending sort order.
+     *
+     * This is useful eg. if it is known that the scan spans only one
+     * partition.
+     */
     if (order_desc) {
       m_descending = true;
       ScanTabReq * req = CAST_PTR(ScanTabReq, theSCAN_TABREQ->getDataPtrSend());
       ScanTabReq::setDescendingFlag(req->requestInfo, true);
     }
-    Uint32 cnt = m_accessTable->getNoOfColumns() - 1;
-    m_sort_columns = cnt; // -1 for NDB$NODE
-    m_current_api_receiver = m_sent_receivers_count;
-    m_api_receivers_count = m_sent_receivers_count;
+    if (order_by) {
+      m_ordered = true;
+      Uint32 cnt = m_accessTable->getNoOfColumns() - 1;
+      m_sort_columns = cnt; // -1 for NDB$NODE
+      m_current_api_receiver = m_sent_receivers_count;
+      m_api_receivers_count = m_sent_receivers_count;
     
-    m_sort_columns = cnt;
-    for(Uint32 i = 0; i<cnt; i++){
-      const NdbColumnImpl* key = m_accessTable->m_index->m_columns[i];
-      const NdbColumnImpl* col = m_currentTable->getColumn(key->m_keyInfoPos);
-      NdbRecAttr* tmp = NdbScanOperation::getValue_impl(col, (char*)-1);
-      UintPtr newVal = UintPtr(tmp);
-      theTupleKeyDefined[i][0] = FAKE_PTR;
-      theTupleKeyDefined[i][1] = (newVal & 0xFFFFFFFF);
+      m_sort_columns = cnt;
+      for(Uint32 i = 0; i<cnt; i++){
+        const NdbColumnImpl* key = m_accessTable->m_index->m_columns[i];
+        const NdbColumnImpl* col = m_currentTable->getColumn(key->m_keyInfoPos);
+        NdbRecAttr* tmp = NdbScanOperation::getValue_impl(col, (char*)-1);
+        UintPtr newVal = UintPtr(tmp);
+        theTupleKeyDefined[i][0] = FAKE_PTR;
+        theTupleKeyDefined[i][1] = (newVal & 0xFFFFFFFF);
 #if (SIZEOF_CHARP == 8)
-      theTupleKeyDefined[i][2] = (newVal >> 32);
+        theTupleKeyDefined[i][2] = (newVal >> 32);
 #endif
+      }
     }
   }
   m_this_bound_start = 0;