Recursion support made for SP (BUG#10100).

client/mysqltest.c:
  An expected error messages hiding from the log if disable_result_log is in force.
mysql-test/r/sp-dynamic.result:
  The test expanded for case of allowed/disalowed recursion.
mysql-test/r/sp-error.result:
  Error messages changed.
  Test of bug11394() made with allowed recursion.
mysql-test/r/sp.result:
  Tests for recursion.
mysql-test/r/trigger.result:
  Check that triggers are not affected by this patch.
mysql-test/r/variables.result:
  Test of max_sp_recursion_depth variable.
mysql-test/t/sp-dynamic.test:
  The test expanded for case of allowed/disalowed recursion.
mysql-test/t/sp-error.test:
  Error messages changed.
  Test of bug11394() made with allowed recursion.
mysql-test/t/sp.test:
  Tests for recursion.
mysql-test/t/trigger.test:
  Check that triggers are not affected by this patch.
mysql-test/t/variables.test:
  Test of max_sp_recursion_depth variable.
sql/item_func.cc:
  sp_find_function() and sp_find_procedure() joined to sp_find_routine()
    function as it was mentioned in TODO.
sql/mysqld.cc:
  max_sp_recursion_depth variable added.
sql/set_var.cc:
  max_sp_recursion_depth variable added.
sql/share/errmsg.txt:
  An error message changed.
  An error message added.
sql/sp.cc:
  sp_find_function() and sp_find_procedure() joined to sp_find_routine()
    function as it was mentioned in TODO.
  Temory LEX is allocated on a stack, not on a heap.
  Recursion support added for stored procedures.
sql/sp.h:
  sp_find_function() and sp_find_procedure() joined to sp_find_routine()
    function as it was mentioned in TODO.
sql/sp_head.cc:
  Initialization of new sp_head fields to get correct list of instances
    contained one instance only.
  Stack requirement for SP instruction is increased.
  Stack free space is checked before mem root initialisation to avoid
    memory leak.
  Pointer to the free instance management added before and after
    SP execution.
sql/sp_head.h:
  New sp_head variables added to support inst of instances of SP
    for recursion and pointer on ths first free to use instance.
sql/sql_base.cc:
  open_table() consume a lot of stack space so we check free stack space before it.
sql/sql_class.h:
  max_sp_recursion_depth variable added.
sql/sql_parse.cc:
  sp_find_function() and sp_find_procedure() joined to sp_find_routine()
    function as it was mentioned in TODO.

1 files changed, 70 insertions, 26 deletions

diff --git a/sql/sp_head.cc b/sql/sp_head.cc
index abc66ce0b21..cb0413947df 100644
--- a/sql/sp_head.cc
+++ b/sql/sp_head.cc
@@ -437,7 +437,8 @@ sp_head::operator delete(void *ptr, size_t size)
 
 sp_head::sp_head()
   :Query_arena(&main_mem_root, INITIALIZED_FOR_SP),
-   m_flags(0), m_returns_cs(NULL)
+   m_flags(0), m_returns_cs(NULL), m_recursion_level(0), m_next_cached_sp(0),
+   m_first_instance(this), m_first_free_instance(this), m_last_cached_sp(this)
 {
   extern byte *
     sp_table_key(const byte *ptr, uint *plen, my_bool first);
@@ -615,6 +616,7 @@ sp_head::create(THD *thd)
 sp_head::~sp_head()
 {
   destroy();
+  delete m_next_cached_sp;
   if (m_thd)
     restore_thd_mem_root(m_thd);
 }
@@ -841,6 +843,31 @@ static bool subst_spvars(THD *thd, sp_instr *instr, LEX_STRING *query_str)
 
 
 /*
+  Return appropriate error about recursion limit reaching
+
+  SYNOPSIS
+    sp_head::recursion_level_error()
+
+  NOTE
+    For functions and triggers we return error about prohibited recursion.
+    For stored procedures we return about reaching recursion limit.
+*/
+
+void sp_head::recursion_level_error()
+{
+  if (m_type == TYPE_ENUM_PROCEDURE)
+  {
+    THD *thd= current_thd;
+    my_error(ER_SP_RECURSION_LIMIT, MYF(0),
+             thd->variables.max_sp_recursion_depth,
+             m_name);
+  }
+  else
+    my_error(ER_SP_NO_RECURSION, MYF(0));
+}
+
+
+/*
   Execute the routine. The main instruction jump loop is there 
   Assume the parameters already set.
   
@@ -869,37 +896,31 @@ int sp_head::execute(THD *thd)
   Item_change_list old_change_list;
   String old_packet;
 
-  /* init per-instruction memroot */
-  init_alloc_root(&execute_mem_root, MEM_ROOT_BLOCK_SIZE, 0);
-
-
   /* Use some extra margin for possible SP recursion and functions */
-  if (check_stack_overrun(thd, 4*STACK_MIN_SIZE, olddb))
+  if (check_stack_overrun(thd, 8 * STACK_MIN_SIZE, (char*)&old_packet))
   {
     DBUG_RETURN(-1);
   }
 
-  if (m_flags & IS_INVOKED)
-  {
-    /*
-      We have to disable recursion for stored routines since in
-      many cases LEX structure and many Item's can't be used in
-      reentrant way now.
-
-      TODO: We can circumvent this problem by using separate
-      sp_head instances for each recursive invocation.
-
-      NOTE: Theoretically arguments of procedure can be evaluated
-      before its invocation so there should be no problem with
-      recursion. But since we perform cleanup for CALL statement
-      as for any other statement only after its execution, its LEX
-      structure is not reusable for recursive calls. Thus we have
-      to prohibit recursion for stored procedures too.
-    */
-    my_error(ER_SP_NO_RECURSION, MYF(0));
-    DBUG_RETURN(-1);
-  }
+  /* init per-instruction memroot */
+  init_alloc_root(&execute_mem_root, MEM_ROOT_BLOCK_SIZE, 0);
+
+  DBUG_ASSERT(!(m_flags & IS_INVOKED));
   m_flags|= IS_INVOKED;
+  m_first_instance->m_first_free_instance= m_next_cached_sp;
+  DBUG_PRINT("info", ("first free for 0x%lx ++: 0x%lx->0x%lx, level: %lu, flags %x",
+                      (ulong)m_first_instance, this, m_next_cached_sp,
+                      m_next_cached_sp->m_recursion_level,
+                      m_next_cached_sp->m_flags));
+  /*
+    Check that if there are not any instances after this one then
+    pointer to the last instance points on this instance or if there are
+    some instances after this one then recursion level of next instance
+    greater then recursion level of current instance on 1
+  */
+  DBUG_ASSERT((m_next_cached_sp == 0 &&
+               m_first_instance->m_last_cached_sp == this) ||
+              (m_recursion_level + 1 == m_next_cached_sp->m_recursion_level));
 
   dbchanged= FALSE;
   if (m_db.length &&
@@ -1074,6 +1095,29 @@ int sp_head::execute(THD *thd)
       ret= mysql_change_db(thd, olddb, 1);
   }
   m_flags&= ~IS_INVOKED;
+  DBUG_PRINT("info", ("first free for 0x%lx --: 0x%lx->0x%lx, level: %lu, flags %x",
+                      (ulong)m_first_instance,
+                      m_first_instance->m_first_free_instance, this,
+                      m_recursion_level, m_flags));
+  /*
+    Check that we have one of following:
+
+    1) there are not free instances which means that this instance is last
+    in the list of instances (pointer to the last instance point on it and
+    ther are not other instances after this one in the list)
+
+    2) There are some free instances which mean that first free instance
+    should go just after this one and recursion level of that free instance
+    should be on 1 more then recursion leven of this instance.
+  */
+  DBUG_ASSERT((m_first_instance->m_first_free_instance == 0 &&
+               this == m_first_instance->m_last_cached_sp &&
+               m_next_cached_sp == 0) ||
+              (m_first_instance->m_first_free_instance != 0 &&
+               m_first_instance->m_first_free_instance == m_next_cached_sp &&
+               m_first_instance->m_first_free_instance->m_recursion_level ==
+               m_recursion_level + 1));
+  m_first_instance->m_first_free_instance= this;
   DBUG_RETURN(ret);
 }