Fix for bug#5138: hash indexes on heap tables support statistics.

 KEY::rec_per_key is updated every time 1/HEAP_STATS_UPDATE_THRESHOLD part of table records has been changed.


heap/_check.c:
  Hash indexes on heap tables now support statistics - number of hash buckets. The value is updated on any insert/delete operation.
heap/hp_clear.c:
  Hash indexes on heap tables now support statistics - number of hash buckets. The value is updated on any insert/delete operation.
heap/hp_create.c:
  Hash indexes on heap tables now support statistics - number of hash buckets. The value is updated on any insert/delete operation.
heap/hp_delete.c:
  Hash indexes on heap tables now support statistics - number of hash buckets. The value is updated on any insert/delete operation.
heap/hp_hash.c:
  Hash indexes on heap tables now support statistics - number of hash buckets. The value is updated on any insert/delete operation.
heap/hp_write.c:
  Hash indexes on heap tables now support statistics - number of hash buckets. The value is updated on any insert/delete operation.
include/heap.h:
  Hash indexes on heap tables now support statistics - number of hash buckets. The value is updated on any insert/delete operation.
mysql-test/r/heap.result:
  Fix for bug#5138: store/use statistics for hash indexes on heap tables
mysql-test/r/heap_hash.result:
  Fix for bug#5138: store/use statistics for hash indexes on heap tables
mysql-test/r/myisam.result:
  Fix for bug#5138: store/use statistics for hash indexes on heap tables
mysql-test/t/heap_hash.test:
  Fix for bug#5138: store/use statistics for hash indexes on heap tables
sql/structs.h:
  Added comments

1 files changed, 6 insertions, 4 deletions

diff --git a/sql/ha_heap.h b/sql/ha_heap.h
index 9ca6b9b76b6..f36e9f31c55 100644
--- a/sql/ha_heap.h
+++ b/sql/ha_heap.h
@@ -27,9 +27,10 @@ class ha_heap: public handler
 {
   HP_INFO *file;
   key_map btree_keys;
-
- public:
-  ha_heap(TABLE *table): handler(table), file(0) {}
+  /* number of records changed since last statistics update */
+  uint    records_changed;
+public:
+  ha_heap(TABLE *table): handler(table), file(0), records_changed(0) {}
   ~ha_heap() {}
   const char *table_type() const { return "HEAP"; }
   const char *index_type(uint inx)
@@ -91,5 +92,6 @@ class ha_heap: public handler
 
   THR_LOCK_DATA **store_lock(THD *thd, THR_LOCK_DATA **to,
 			     enum thr_lock_type lock_type);
-
+private:
+  void update_key_stats();
 };