[SHOW] EXPLAIN UPDATE/DELETE, code re-structuring

- Handle statements inside SPs:
  = regular statements
  = SET command, which does not have its own statement.

- Handle execution of subquery from range optimizer: 
  allocate subquery QPFs on the same MEM_ROOT as the whole 
  query plan was allocated.

1 files changed, 4 insertions, 2 deletions

diff --git a/sql/sp_head.cc b/sql/sp_head.cc
index 3cc3a3893bb..2ad03f3d0dc 100644
--- a/sql/sp_head.cc
+++ b/sql/sp_head.cc
@@ -2973,6 +2973,7 @@ sp_lex_keeper::reset_lex_and_exec_core(THD *thd, uint *nextp,
   }
 
   reinit_stmt_before_use(thd, m_lex);
+  // not here, but inside every instr: create_qpf_query(m_lex);
 
   if (open_tables)
     res= instr->exec_open_and_lock_tables(thd, m_lex->query_tables);
@@ -3007,8 +3008,7 @@ sp_lex_keeper::reset_lex_and_exec_core(THD *thd, uint *nextp,
       thd->mdl_context.release_statement_locks();
   }
   
-  delete_qpf_query(m_lex->query_plan_footprint);
-  m_lex->query_plan_footprint= NULL;
+  delete_qpf_query(m_lex);
 
   if (m_lex->query_tables_own_last)
   {
@@ -3212,6 +3212,7 @@ sp_instr_set::execute(THD *thd, uint *nextp)
 int
 sp_instr_set::exec_core(THD *thd, uint *nextp)
 {
+  create_qpf_query(thd->lex, thd->mem_root);
   int res= thd->spcont->set_variable(thd, m_offset, &m_value);
 
   if (res)
@@ -3224,6 +3225,7 @@ sp_instr_set::exec_core(THD *thd, uint *nextp)
       my_error(ER_OUT_OF_RESOURCES, MYF(ME_FATALERROR));
     }
   }
+  delete_qpf_query(thd->lex);
 
   *nextp = m_ip+1;
   return res;