Bug #12796: Record lost in HEAP table

Two handler objects were present, one was used for an insert and the other for a select
The state of the statistics was local to the handler object and thus the other handler
object didn't notice the insert.
Fix included:
1) Add a new variable key_stat_version added to whenever statistics was considered in need
of update (previously key_stats_ok= FALSE in those places)
2) Add a new handler variable key_stat_version assigned whenever key_stats_ok= TRUE was set
previously
3) Fix records_in_range to return records if records <= 1
4) Fix records_in_range to add 2 to rec_per_key to ensure we don't specify 0 or 1 when it isn't
and thus invoking incorrect optimisations.
5) Fix unique key handling for HEAP table in records_in_range

1 files changed, 2 insertions, 2 deletions

diff --git a/sql/ha_heap.h b/sql/ha_heap.h
index cbe2474492d..0a087fde1b0 100644
--- a/sql/ha_heap.h
+++ b/sql/ha_heap.h
@@ -29,10 +29,10 @@ class ha_heap: public handler
   key_map btree_keys;
   /* number of records changed since last statistics update */
   uint    records_changed;
-  bool    key_stats_ok;
+  uint    key_stat_version;
 public:
   ha_heap(TABLE *table): handler(table), file(0), records_changed(0),
-      key_stats_ok(0) {}
+      key_stat_version(0) {}
   ~ha_heap() {}
   const char *table_type() const { return "HEAP"; }
   const char *index_type(uint inx)