1 files changed, 16 insertions, 11 deletions

diff --git a/sql/sql_join_cache.h b/sql/sql_join_cache.h
index 10a8c5fd831..f6c0ebdbaf3 100644
--- a/sql/sql_join_cache.h
+++ b/sql/sql_join_cache.h
@@ -63,12 +63,14 @@ typedef struct st_cache_field {
 
 class JOIN_TAB_SCAN;
 
+struct st_explain_bka_type;
 
 /*
   JOIN_CACHE is the base class to support the implementations of 
   - Block Nested Loop (BNL) Join Algorithm,
   - Block Nested Loop Hash (BNLH) Join Algorithm,
   - Batched Key Access (BKA) Join Algorithm.
+
   The first algorithm is supported by the derived class JOIN_CACHE_BNL,
   the second algorithm is supported by the derived class JOIN_CACHE_BNLH,
   while the third algorithm is implemented in two variant supported by
@@ -97,6 +99,9 @@ private:
   /* Size of the offset of a field within a record in the cache */   
   uint size_of_fld_ofs;
 
+  /* This structure is used only for explain, not for execution */
+  bool for_explain_only;
+
 protected:
        
   /* 3 functions below actually do not use the hidden parameter 'this' */ 
@@ -420,7 +425,7 @@ protected:
   /* Shall calculate how much space is remaining in the join buffer */ 
   virtual size_t rem_space() 
   { 
-    return max(buff_size-(end_pos-buff)-aux_buff_size,0);
+    return MY_MAX(buff_size-(end_pos-buff)-aux_buff_size,0);
   }
 
   /* 
@@ -593,7 +598,7 @@ public:
   JOIN_CACHE *next_cache;
 
   /* Shall initialize the join cache structure */ 
-  virtual int init();
+  virtual int init(bool for_explain);
 
   /* Get the current size of the cache join buffer */ 
   size_t get_join_buffer_size() { return buff_size; }
@@ -657,7 +662,7 @@ public:
   enum_nested_loop_state join_records(bool skip_last);
 
   /* Add a comment on the join algorithm employed by the join cache */
-  virtual void print_explain_comment(String *str);
+  virtual void save_explain_data(struct st_explain_bka_type *explain);
 
   THD *thd();
 
@@ -943,7 +948,7 @@ protected:
   */ 
   size_t rem_space() 
   { 
-    return max(last_key_entry-end_pos-aux_buff_size,0);
+    return MY_MAX(last_key_entry-end_pos-aux_buff_size,0);
   }
 
   /* 
@@ -989,7 +994,7 @@ protected:
 public:
 
   /* Initialize a hashed join cache */       
-  int init();
+  int init(bool for_explain);
 
   /* Reset the buffer of a hashed join cache for reading/writing */
   void reset(bool for_writing);
@@ -1125,7 +1130,7 @@ public:
     :JOIN_CACHE(j, tab, prev) {}
 
   /* Initialize the BNL cache */       
-  int init();
+  int init(bool for_explain);
 
   enum Join_algorithm get_join_alg() { return BNL_JOIN_ALG; }
 
@@ -1192,7 +1197,7 @@ public:
     : JOIN_CACHE_HASHED(j, tab, prev) {}
 
   /* Initialize the BNLH cache */       
-  int init();
+  int init(bool for_explain);
 
   enum Join_algorithm get_join_alg() { return BNLH_JOIN_ALG; }
 
@@ -1323,7 +1328,7 @@ public:
   uchar **get_curr_association_ptr() { return &curr_association; }
 
   /* Initialize the BKA cache */       
-  int init();
+  int init(bool for_explain);
 
   enum Join_algorithm get_join_alg() { return BKA_JOIN_ALG; }
 
@@ -1335,7 +1340,7 @@ public:
   /* Check index condition of the joined table for a record from BKA cache */
   bool skip_index_tuple(range_id_t range_info);
 
-  void print_explain_comment(String *str);
+  void save_explain_data(struct st_explain_bka_type *explain);
 };
 
 
@@ -1419,12 +1424,12 @@ public:
   uchar **get_curr_association_ptr() { return &curr_matching_chain; }
 
   /* Initialize the BKAH cache */       
-  int init();
+  int init(bool for_explain);
 
   enum Join_algorithm get_join_alg() { return BKAH_JOIN_ALG; }
 
   /* Check index condition of the joined table for a record from BKAH cache */
   bool skip_index_tuple(range_id_t range_info);
 
-  void print_explain_comment(String *str);
+  void save_explain_data(struct st_explain_bka_type *explain);
 };