merge

Docs/manual.texi:
  Auto merged
mysql-test/t/join_outer.test:
  Auto merged
mysql-test/t/null.test:
  Auto merged
sql/mysqld.cc:
  Auto merged
sql/sql_select.cc:
  Auto merged
sql/slave.cc:
  keep local copy

Docs/manual.texi

@@ -48849,6 +48849,14 @@ not yet 100% confident in this code.
 @appendixsubsec Changes in release 3.23.44
 @itemize @bullet
 @item
+Don't use @code{signal()} on windows because this appears to not be
+100 % reliable.
+@item
+Fixed bug when doing @code{WHERE column_name=NULL} on an indexed column
+that had @code{NULL} values.
+@item
+Fixed bug when doing @code{LEFT JOIN ...  ON (column_name = constant) WHERE column_name = constant}.
+@item
 When using replications, aborted queries that contained @code{%} could cause
 a core dum.
 @item

mysql-test/t/join_outer.test

@@ -394,3 +394,13 @@ INSERT INTO t2 VALUES (1,1);
 explain SELECT * from t1 left join t2 on t1.id=t2.id where t2.id IS NULL;
 SELECT * from t1 left join t2 on t1.id=t2.id where t2.id IS NULL;
 drop table t1,t2;
+
+#
+# Test problem with using key_column= constant in ON and WHERE
+#
+create table t1 (bug_id mediumint, reporter mediumint);
+create table t2 (bug_id mediumint, who mediumint, index(who));
+insert into t2 values (1,1),(1,2);
+insert into t1 values (1,1),(2,1);
+SELECT * FROM t1 LEFT JOIN t2 ON (t1.bug_id =  t2.bug_id AND  t2.who = 2) WHERE  (t1.reporter = 2 OR t2.who = 2);
+drop table t1,t2;

mysql-test/t/null.test

@@ -20,3 +20,18 @@ create table t1 (x int);
 insert into t1 values (null);
 select * from t1 where x != 0;
 drop table t1;
+
+#
+# Test problem med index on NULL columns and testing with =NULL;
+#
+
+DROP TABLE IF EXISTS t1;
+CREATE TABLE t1 (
+  indexed_field int default NULL,
+  KEY indexed_field (indexed_field)
+);
+INSERT INTO t1 VALUES (NULL),(NULL);
+SELECT * FROM t1 WHERE indexed_field=NULL;
+SELECT * FROM t1 WHERE indexed_field IS NULL;
+SELECT * FROM t1 WHERE indexed_field<=>NULL;
+DROP TABLE t1;

sql/mysqld.cc

@@ -2937,13 +2937,21 @@ struct show_var_st init_vars[]= {
   {"have_openssl",	      (char*) &have_openssl,		    SHOW_HAVE},
   {"init_file",               (char*) &opt_init_file,               SHOW_CHAR_PTR},
 #ifdef HAVE_INNOBASE_DB
+  {"innodb_additional_mem_pool_size", (char*) &innobase_additional_mem_pool_size, SHOW_LONG },
+  {"innodb_buffer_pool_size", (char*) &innobase_buffer_pool_size, SHOW_LONG },
   {"innodb_data_file_path", (char*) &innobase_data_file_path,	    SHOW_CHAR_PTR},
   {"innodb_data_home_dir",  (char*) &innobase_data_home_dir,	    SHOW_CHAR_PTR},
+  {"innodb_file_io_threads", (char*) &innobase_file_io_threads, SHOW_LONG },
   {"innodb_flush_log_at_trx_commit", (char*) &innobase_flush_log_at_trx_commit, SHOW_MY_BOOL},
+  {"innodb_flush_method",    (char*) &innobase_unix_file_flush_method, SHOW_CHAR_PTR},
+  {"innodb_lock_wait_timeout", (char*) &innobase_lock_wait_timeout, SHOW_LONG },
   {"innodb_log_arch_dir",   (char*) &innobase_log_arch_dir, 	    SHOW_CHAR_PTR},
   {"innodb_log_archive",    (char*) &innobase_log_archive, 	    SHOW_MY_BOOL},
+  {"innodb_log_buffer_size", (char*) &innobase_log_buffer_size, SHOW_LONG },
+  {"innodb_log_file_size", (char*) &innobase_log_file_size, SHOW_LONG},
+  {"innodb_log_files_in_group", (char*) &innobase_log_files_in_group,	SHOW_LONG},
   {"innodb_log_group_home_dir", (char*) &innobase_log_group_home_dir, SHOW_CHAR_PTR},
-  {"innodb_flush_method",    (char*) &innobase_unix_file_flush_method, SHOW_CHAR_PTR},
+  {"innodb_mirrored_log_groups", (char*) &innobase_mirrored_log_groups, SHOW_LONG},
 #endif
   {"interactive_timeout",     (char*) &net_interactive_timeout,     SHOW_LONG},
   {"join_buffer_size",        (char*) &join_buff_size,              SHOW_LONG},

sql/sql_select.cc

@@ -5084,15 +5084,16 @@ end_write_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
 static bool test_if_ref(Item_field *left_item,Item *right_item)
 {
   Field *field=left_item->field;
-  if (!field->table->const_table)		// No need to change const test
+  // No need to change const test. We also have to keep tests on LEFT JOIN
+  if (!field->table->const_table && !field->table->maybe_null)
   {
     Item *ref_item=part_of_refkey(field->table,field);
     if (ref_item && ref_item->eq(right_item))
     {
       if (right_item->type() == Item::FIELD_ITEM)
-	return (field->eq_def(((Item_field *) right_item)->field) &&
-		!field->table->maybe_null);
-      if (right_item->const_item())
+	return (field->eq_def(((Item_field *) right_item)->field));
+      if (right_item->const_item() &&
+	  (right_item->val_int() || !right_item->null_value))
       {
 	// We can remove binary fields and numerical fields except float,
 	// as float comparison isn't 100 % secure