MDEV-7811: EXPLAIN/ANALYZE FORMAT=JSON should show subquery cache

1 files changed, 11 insertions, 5 deletions

diff --git a/sql/sql_explain.h b/sql/sql_explain.h
index dd2b5783b41..427553c1088 100644
--- a/sql/sql_explain.h
+++ b/sql/sql_explain.h
@@ -84,9 +84,10 @@ class Explain_query;
 class Explain_node : public Sql_alloc
 {
 public:
-  Explain_node(MEM_ROOT *root) : 
-     connection_type(EXPLAIN_NODE_OTHER),
-     children(root)
+  Explain_node(MEM_ROOT *root) :
+    cache_stat(NULL),
+    connection_type(EXPLAIN_NODE_OTHER),
+    children(root)
   {}
   /* A type specifying what kind of node this is */
   enum explain_node_type 
@@ -106,10 +107,14 @@ public:
     EXPLAIN_NODE_NON_MERGED_SJ /* aka JTBM semi-join */
   };
 
-
   virtual enum explain_node_type get_type()= 0;
   virtual int get_select_id()= 0;
 
+  /**
+    expression cache statistics
+  */
+  Expression_cache_stat* cache_stat;
+
   /*
     How this node is connected to its parent.
     (NOTE: EXPLAIN_NODE_NON_MERGED_SJ is set very late currently)
@@ -135,6 +140,7 @@ public:
                                  uint8 explain_flags, bool is_analyze);
   void print_explain_json_for_children(Explain_query *query,
                                        Json_writer *writer, bool is_analyze);
+  void print_explain_json_cache(Json_writer *writer, bool is_analyze);
   virtual ~Explain_node(){}
 };
 
@@ -221,7 +227,7 @@ public:
     members have no info 
   */
   const char *message;
-  
+
   /* Expensive constant condition */
   Item *exec_const_cond;