Bug#52455: Subpar INSERT ON DUPLICATE KEY UPDATE performance with many partitions

The handler function for reading one row from a specific index
was not optimized in the partitioning handler since it
used the default implementation.

No test case since it is performance only, verified by hand.

sql/ha_partition.cc:
  Implemented a optimized version of index_read_idx_map
  for the case when find flag == HA_READ_KEY_EXACT,
  which is the common case.
sql/ha_partition.h:
  Declared ha_partition::index_read_idx_map

1 files changed, 9 insertions, 0 deletions

diff --git a/sql/ha_partition.h b/sql/ha_partition.h
index 9f6d9e0a5ba..d8872d37a09 100644
--- a/sql/ha_partition.h
+++ b/sql/ha_partition.h
@@ -448,6 +448,15 @@ public:
   virtual int index_init(uint idx, bool sorted);
   virtual int index_end();
 
+  /**
+    @breif
+    Positions an index cursor to the index specified in the hanlde. Fetches the
+    row if available. If the key value is null, begin at first key of the
+    index.
+  */
+  virtual int index_read_idx_map(uchar *buf, uint index, const uchar *key,
+                                 key_part_map keypart_map,
+                                 enum ha_rkey_function find_flag);
   /*
     These methods are used to jump to next or previous entry in the index
     scan. There are also methods to jump to first and last entry.