BUG#18558 "Partition pruning results are incorrect for certain class of WHERE clauses" :

* Produce right results for conditions that were transformed to "(partitioning_range) AND
  (list_of_subpartitioning_ranges)": make each partition id set iterator auto-reset itself
  after it has returned all partition ids in the sequence 
* Fix "Range mapping" and "Range mapping" partitioning interval analysis functions to 
  correctly deal with NULL values. 


mysql-test/r/partition_pruning.result:
  Testcase for BUG#18558
mysql-test/t/partition_pruning.test:
  Testcase for BUG#18558
sql/opt_range.cc:
  BUG#18558: Move partition set iterator initialization to sql_partition.cc, comment fixes
sql/partition_info.h:
  BUG#18558: Make each partition set iterator auto-reset itself after it has returned all 
  partition ids in the set it enumerates.
sql/sql_partition.cc:
  BUG#18558: 
  - Make each partition set iterator auto-reset itself after it has returned all 
    partition ids in the set it enumerates. 
  - Fix partition interval analysis to correctly handle intervals with one or both
    NULL bounds.
sql/sql_partition.h:
  BUG#18558: 
   - Make each partition set iterator auto-reset itself after it has returned all 
     partition ids in the set it enumerates. 
   - Rename PARTITION_ITERATOR::has_null_value to ret_null_part

1 files changed, 17 insertions, 1 deletions

diff --git a/sql/sql_partition.h b/sql/sql_partition.h
index c214be81ae4..fd2c474236f 100644
--- a/sql/sql_partition.h
+++ b/sql/sql_partition.h
@@ -94,10 +94,20 @@ uint32 get_partition_id_range_for_endpoint(partition_info *part_info,
 
 /*
   A "Get next" function for partition iterator.
+
   SYNOPSIS
     partition_iter_func()
       part_iter  Partition iterator, you call only "iter.get_next(&iter)"
 
+  DESCRIPTION
+    Depending on whether partitions or sub-partitions are iterated, the
+    function returns next subpartition id/partition number. The sequence of
+    returned numbers is not ordered and may contain duplicates.
+
+    When the end of sequence is reached, NOT_A_PARTITION_ID is returned, and 
+    the iterator resets itself (so next get_next() call will start to 
+    enumerate the set all over again).
+
   RETURN 
     NOT_A_PARTITION_ID if there are no more partitions.
     [sub]partition_id  of the next partition
@@ -124,16 +134,22 @@ typedef uint32 (*partition_iter_func)(st_partition_iter* part_iter);
 typedef struct st_partition_iter
 {
   partition_iter_func get_next;
-  bool has_null_value;
+  /* 
+    Valid for "Interval mapping" in LIST partitioning: if true, let the
+    iterator also produce id of the partition that contains NULL value.
+  */
+  bool ret_null_part, ret_null_part_orig;
   struct st_part_num_range
   {
     uint32 start;
+    uint32 cur;
     uint32 end;
   };
 
   struct st_field_value_range
   {
     longlong start;
+    longlong cur;
     longlong end;
   };