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

Fixes over the original patch:
- Fix variable/class/other names
- Fix the JSON output to be in line with the output of other JSON
  constructs we produce

1 files changed, 9 insertions, 9 deletions

diff --git a/sql/sql_expression_cache.cc b/sql/sql_expression_cache.cc
index bda0aaafebe..cc922c3bcfe 100644
--- a/sql/sql_expression_cache.cc
+++ b/sql/sql_expression_cache.cc
@@ -43,7 +43,7 @@ ulong subquery_cache_miss, subquery_cache_hit;
 Expression_cache_tmptable::Expression_cache_tmptable(THD *thd,
                                                      List<Item> &dependants,
                                                      Item *value)
-  :cache_table(NULL), table_thd(thd), stat(NULL), items(dependants), val(value),
+  :cache_table(NULL), table_thd(thd), tracker(NULL), items(dependants), val(value),
    hit(0), miss(0), inited (0)
 {
   DBUG_ENTER("Expression_cache_tmptable::Expression_cache_tmptable");
@@ -61,9 +61,9 @@ void Expression_cache_tmptable::disable_cache()
     cache_table->file->ha_index_end();
   free_tmp_table(table_thd, cache_table);
   cache_table= NULL;
-  flush_stat();
-  if (stat)
-    stat->cache= NULL;
+  update_tracker();
+  if (tracker)
+    tracker->cache= NULL;
 }
 
 
@@ -167,7 +167,7 @@ void Expression_cache_tmptable::init()
     goto error;
   }
 
-  flush_stat();
+  update_tracker();
   DBUG_VOID_RETURN;
 
 error:
@@ -186,8 +186,8 @@ Expression_cache_tmptable::~Expression_cache_tmptable()
     disable_cache();
   else
   {
-    flush_stat();
-    stat= NULL;
+    update_tracker();
+    tracker= NULL;
   }
 }
 
@@ -334,5 +334,5 @@ void Expression_cache_tmptable::print(String *str, enum_query_type query_type)
 }
 
 
-const char *Expression_cache_stat::state_str[3]=
-{"UNINITIALYZED", "DISABLED", "ENABLED"};
+const char *Expression_cache_tracker::state_str[3]=
+{"uninitialized", "disabled", "enabled"};