Merge remote-tracking branch 'origin/10.4' into 10.5

1 files changed, 73 insertions, 0 deletions

diff --git a/sql/opt_trace.cc b/sql/opt_trace.cc
index 4c9aa43669d..d95f0795542 100644
--- a/sql/opt_trace.cc
+++ b/sql/opt_trace.cc
@@ -416,6 +416,12 @@ size_t Opt_trace_context::remaining_mem_size()
   return max_mem_size;
 }
 
+/*
+  Disable tracing for children if the current trace is already present.
+  Currently only one trace is stored and there is no mechanism
+  to restore traces, so disabling tracing for children is the best option.
+*/
+
 bool Opt_trace_context::disable_tracing_if_required()
 {
   if (current_trace)
@@ -633,6 +639,73 @@ void add_table_scan_values_to_trace(THD *thd, JOIN_TAB *tab)
   table_rec.add("rows", tab->found_records)
            .add("cost", tab->read_time);
 }
+
+
+/*
+  @brief
+    Add the tables inside a partial join to the optimizer trace
+
+  @param join                join handler
+  @param idx                 length of the partial QEP in 'join->positions'
+  @table_map                 map of all non-const tables of the join
+
+  @note
+    This function is used during best_access_path to print the tables
+    inside the partial join that were considered doing the cost based
+    analysis of the various join orders.
+*/
+
+void trace_plan_prefix(JOIN *join, uint idx, table_map join_tables)
+{
+  THD *const thd= join->thd;
+  Json_writer_array plan_prefix(thd, "plan_prefix");
+  for (uint i= 0; i < idx; i++)
+  {
+    TABLE_LIST *const tr= join->positions[i].table->tab_list;
+    if (!(tr->map & join_tables))
+      plan_prefix.add_table_name(join->positions[i].table);
+  }
+}
+
+
+/*
+  Print the join order of all the tables for top level select.
+
+  For example:
+
+  select * from ot1
+   where ot1.a IN (select it1.a from it1, it2 where it1.b=it2.a);
+
+  So this function would print
+    ot1, <subquery2>  ----> For select #1
+*/
+
+void print_final_join_order(JOIN *join)
+{
+  Json_writer_object join_order(join->thd);
+  Json_writer_array  best_order(join->thd, "best_join_order");
+  JOIN_TAB *j;
+  uint i;
+  for (j= join->join_tab,i=0 ; i < join->top_join_tab_count;
+       i++, j++)
+    best_order.add_table_name(j);
+}
+
+
+void print_best_access_for_table(THD *thd, POSITION *pos,
+                                 enum join_type type)
+{
+  Json_writer_object trace_best_access(thd, "chosen_access_method");
+  trace_best_access.add("type", type == JT_ALL ? "scan" :
+                                                 join_type_str[type]);
+  trace_best_access.add("records", pos->records_read);
+  trace_best_access.add("cost", pos->read_time);
+  trace_best_access.add("uses_join_buffering", pos->use_join_buffer);
+  trace_best_access.add("filter_used",
+                         pos->range_rowid_filter_info != NULL);
+}
+
+
 /*
   Introduce enum_query_type flags parameter, maybe also allow
   EXPLAIN also use this function.