Fixes after last merge of MySQL 5.1

- INSERT with RAND() doesn't require row based logging again
- Some bugs fixed in opt_range() where we table->key_read was wrongly used



.bzrignore:
  Ignore new xtstat binary
mysql-test/r/index_merge_myisam.result:
  Update results (old result was wrong)
mysql-test/suite/binlog/r/binlog_stm_binlog.result:
  Added drop table first
mysql-test/suite/binlog/r/binlog_stm_unsafe_warning.result:
  Added test for when RAND() requires row based logging
mysql-test/suite/binlog/t/binlog_stm_binlog.test:
  Added drop table first
mysql-test/suite/binlog/t/binlog_stm_unsafe_warning.test:
  Added test for when RAND() requires row based logging
scripts/make_binary_distribution.sh:
  Removed type from last commit
sql/item_create.cc:
  Don't require row based logging when using RAND() with INSERT
sql/opt_range.cc:
  Revert wrong patch from Oracle:
  - As QUICK_RANGE_SELECT uses it's own 'file' handler to the tables, one can't use 'table->key_read' as a flag to detect if index only read (keyread) is used or not
  - Don't set keyread if keyread is already enabled
  - Don't disable key read, if we didn't enable it ourselves
  - Simplify code (and ensure that we do proper cleanup of index only read)
sql/opt_range.h:
  Added flags to detect if the range optimizer enabled index only read (key read) or not
sql/opt_sum.cc:
  Use our more optimized macros
sql/sql_lex.h:
  Added 'readable' function to check if we are in a sub query function or not (not normal query or sub query in FROM clause)
sql/sql_select.cc:
  Use our more optimized keyread macros
  Added ASSERTS early
  Simplify code on eliminate_item_equal()
  Fixed that substitute_for_best_equal_field() doesn't core dump in case of out of memory conditions.
  Removed not needed test for 'field->maybe_null()'
  Replaced master_unit()->item with is_subquery_function() (More readable)
sql/sql_update.cc:
  Use our more optimized keyread macros
sql/table.cc:
  Use our more optimized keyread macros
sql/table.h:
  Use separate functions to enable/disable Index only reads
  - Safer, more readable, better logging and faster.

16 files changed, 161 insertions, 83 deletions

diff --git a/.bzrignore b/.bzrignore
index 34e7c1cd1c1..a5358590417 100644
--- a/.bzrignore
+++ b/.bzrignore
@@ -1927,3 +1927,4 @@ libmysqld/opt_table_elimination.cc
 libmysqld/ha_federatedx.cc
 tmp
 libmysqld/debug_sync.cc
+storage/pbxt/bin/xtstat
diff --git a/mysql-test/r/index_merge_myisam.result b/mysql-test/r/index_merge_myisam.result
index c4e6a6d3f9c..182455f8c06 100644
--- a/mysql-test/r/index_merge_myisam.result
+++ b/mysql-test/r/index_merge_myisam.result
@@ -286,7 +286,7 @@ NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL
 explain select * from (select * from t1 where key1 = 3 or key2 =3) as Z where key8 >5;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	<derived2>	system	NULL	NULL	NULL	NULL	1	
-2	DERIVED	t1	index_merge	i1,i2	i1,i2	4,4	NULL	2	Using union(i1,i2); Using where; Using index
+2	DERIVED	t1	index_merge	i1,i2	i1,i2	4,4	NULL	2	Using union(i1,i2); Using where
 create table t3 like t0;
 insert into t3 select * from t0;
 alter table t3 add key9 int not null, add index i9(key9);
diff --git a/mysql-test/suite/binlog/r/binlog_stm_binlog.result b/mysql-test/suite/binlog/r/binlog_stm_binlog.result
index eebcfceaa25..a7f79e53895 100644
--- a/mysql-test/suite/binlog/r/binlog_stm_binlog.result
+++ b/mysql-test/suite/binlog/r/binlog_stm_binlog.result
@@ -1,3 +1,4 @@
+drop table if exists t1;
 create table t1 (a int, b int) engine=innodb;
 begin;
 insert into t1 values (1,2);
@@ -5,10 +6,11 @@ commit;
 show binlog events;
 Log_name	Pos	Event_type	Server_id	End_log_pos	Info
 master-bin.000001	4	Format_desc	1	106	Server ver: #, Binlog ver: #
-master-bin.000001	106	Query	1	213	use `test`; create table t1 (a int, b int) engine=innodb
-master-bin.000001	213	Query	1	281	BEGIN
-master-bin.000001	281	Query	1	371	use `test`; insert into t1 values (1,2)
-master-bin.000001	371	Xid	1	398	COMMIT /* XID */
+master-bin.000001	106	Query	1	192	use `test`; drop table if exists t1
+master-bin.000001	192	Query	1	299	use `test`; create table t1 (a int, b int) engine=innodb
+master-bin.000001	299	Query	1	367	BEGIN
+master-bin.000001	367	Query	1	457	use `test`; insert into t1 values (1,2)
+master-bin.000001	457	Xid	1	484	COMMIT /* XID */
 drop table t1;
 drop table if exists t1, t2;
 reset master;
diff --git a/mysql-test/suite/binlog/r/binlog_stm_unsafe_warning.result b/mysql-test/suite/binlog/r/binlog_stm_unsafe_warning.result
index edbd878982b..eb056468f60 100644
--- a/mysql-test/suite/binlog/r/binlog_stm_unsafe_warning.result
+++ b/mysql-test/suite/binlog/r/binlog_stm_unsafe_warning.result
@@ -48,3 +48,16 @@ SET GLOBAL log_warnings = @old_log_warnings;
 # Count the number of times the "Unsafe" message was printed
 # to the error log.
 Occurrences: 1
+create table t1 (n1 int, n2 int, n3 int,
+key (n1, n2, n3),
+key (n2, n3, n1),
+key (n3, n1, n2));
+insert into t1 values (1,1,1);
+insert into t1 values (RAND()*1000+10, RAND()*1000+10, RAND()*1000+10);
+update t1 set n1=rand() where n1=1;
+Warnings:
+Note	1592	Statement may not be safe to log in statement format.
+delete from t1 where n2=1 + rand()*0;
+Warnings:
+Note	1592	Statement may not be safe to log in statement format.
+drop table t1;
diff --git a/mysql-test/suite/binlog/t/binlog_stm_binlog.test b/mysql-test/suite/binlog/t/binlog_stm_binlog.test
index 280b7a3aef9..a8afe4d3b8c 100644
--- a/mysql-test/suite/binlog/t/binlog_stm_binlog.test
+++ b/mysql-test/suite/binlog/t/binlog_stm_binlog.test
@@ -1,3 +1,10 @@
+-- source include/not_embedded.inc
+-- source include/have_binlog_format_mixed.inc
+
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+
 # REQUIREMENT
 #   replace_regex should replace output of SHOW BINLOG EVENTS
 
@@ -12,7 +19,4 @@ drop table t1;
 # This is a wrapper for binlog.test so that the same test case can be used 
 # For both statement and row based bin logs 9/19/2005 [jbm]
 
--- source include/not_embedded.inc
--- source include/have_binlog_format_mixed.inc
 -- source extra/binlog_tests/binlog.test
-
diff --git a/mysql-test/suite/binlog/t/binlog_stm_unsafe_warning.test b/mysql-test/suite/binlog/t/binlog_stm_unsafe_warning.test
index 21c11d5a3df..d09f4e433ac 100644
--- a/mysql-test/suite/binlog/t/binlog_stm_unsafe_warning.test
+++ b/mysql-test/suite/binlog/t/binlog_stm_unsafe_warning.test
@@ -115,3 +115,19 @@ perl;
   print "Occurrences: $count\n";
   close(FILE);
 EOF
+
+#
+# Check how RAND() can be used with replication
+#
+
+create table t1 (n1 int, n2 int, n3 int,
+                key (n1, n2, n3),
+                key (n2, n3, n1),
+                key (n3, n1, n2));
+insert into t1 values (1,1,1);
+# This should work fine
+insert into t1 values (RAND()*1000+10, RAND()*1000+10, RAND()*1000+10);
+# This should need row based logging.
+update t1 set n1=rand() where n1=1;
+delete from t1 where n2=1 + rand()*0;
+drop table t1;
diff --git a/scripts/make_binary_distribution.sh b/scripts/make_binary_distribution.sh
index 44505adf6e1..eb2cc94afe9 100644
--- a/scripts/make_binary_distribution.sh
+++ b/scripts/make_binary_distribution.sh
@@ -276,7 +276,7 @@ if [ x"$BASE_SYSTEM" != x"netware" ] ; then
   # Do a install that we later are to pack. Use the same paths as in
   # the build for the relevant directories.
   # ----------------------------------------------------------------------
-  set -x -v
+
   @MAKE@ DESTDIR=$BASE install \
     pkglibdir=@pkglibdir@ \
     pkgincludedir=@pkgincludedir@ \
diff --git a/sql/item_create.cc b/sql/item_create.cc
index 8541557c011..2e72ab24fb0 100644
--- a/sql/item_create.cc
+++ b/sql/item_create.cc
@@ -4185,8 +4185,11 @@ Create_func_rand::create_native(THD *thd, LEX_STRING name,
     into a table, the order in which the rows are modified may differ
     between master and slave, because the order is undefined.  Hence,
     the statement is unsafe to log in statement format.
+
+    For normal INSERT's this is howevever safe
   */
-  thd->lex->set_stmt_unsafe();
+  if (thd->lex->sql_command != SQLCOM_INSERT)
+    thd->lex->set_stmt_unsafe();
 
   switch (arg_count) {
   case 0:
diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index 280154c0b52..160175f9ee3 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -1100,7 +1100,7 @@ QUICK_SELECT_I::QUICK_SELECT_I()
 
 QUICK_RANGE_SELECT::QUICK_RANGE_SELECT(THD *thd, TABLE *table, uint key_nr,
                                        bool no_alloc, MEM_ROOT *parent_alloc)
-  :dont_free(0),error(0),free_file(0),in_range(0),cur_range(NULL),last_range(0)
+  :dont_free(0),doing_key_read(0),error(0),free_file(0),in_range(0),cur_range(NULL),last_range(0)
 {
   my_bitmap_map *bitmap;
   DBUG_ENTER("QUICK_RANGE_SELECT::QUICK_RANGE_SELECT");
@@ -1171,7 +1171,8 @@ QUICK_RANGE_SELECT::~QUICK_RANGE_SELECT()
     if (file) 
     {
       range_end();
-      head->set_keyread(FALSE);
+      if (doing_key_read)
+        file->extra(HA_EXTRA_NO_KEYREAD);
       if (free_file)
       {
         DBUG_PRINT("info", ("Freeing separate handler 0x%lx (free: %d)", (long) file,
@@ -1311,6 +1312,7 @@ int QUICK_ROR_INTERSECT_SELECT::init()
 int QUICK_RANGE_SELECT::init_ror_merged_scan(bool reuse_handler)
 {
   handler *save_file= file, *org_file;
+  my_bool org_key_read;
   THD *thd;
   DBUG_ENTER("QUICK_RANGE_SELECT::init_ror_merged_scan");
 
@@ -1370,12 +1372,17 @@ end:
     The now bitmap is stored in 'column_bitmap' which is used in ::get_next()
   */
   org_file= head->file;
+  org_key_read= head->key_read;
   head->file= file;
-  /* We don't have to set 'head->keyread' here as the 'file' is unique */
+  head->key_read= 0;
   if (!head->no_keyread)
+  {
+    doing_key_read= 1;
     head->mark_columns_used_by_index(index);
+  }
   head->prepare_for_position();
   head->file= org_file;
+  head->key_read= org_key_read;
   bitmap_copy(&column_bitmap, head->read_set);
   head->column_bitmaps_set(&column_bitmap, &column_bitmap);
 
@@ -8154,12 +8161,15 @@ int QUICK_INDEX_MERGE_SELECT::read_keys_and_merge()
   List_iterator_fast<QUICK_RANGE_SELECT> cur_quick_it(quick_selects);
   QUICK_RANGE_SELECT* cur_quick;
   int result;
-  Unique *unique;
+  Unique *unique= 0;
   handler *file= head->file;
   DBUG_ENTER("QUICK_INDEX_MERGE_SELECT::read_keys_and_merge");
 
   /* We're going to just read rowids. */
-  head->set_keyread(TRUE);
+  if (!head->key_read)
+  {
+    head->enable_keyread();
+  }
   head->prepare_for_position();
 
   cur_quick_it.rewind();
@@ -8171,13 +8181,13 @@ int QUICK_INDEX_MERGE_SELECT::read_keys_and_merge()
     reset here.
   */
   if (cur_quick->init() || cur_quick->reset())
-    DBUG_RETURN(1);
+    goto err;
 
   unique= new Unique(refpos_order_cmp, (void *)file,
                      file->ref_length,
                      thd->variables.sortbuff_size);
   if (!unique)
-    DBUG_RETURN(1);
+    goto err;
   for (;;)
   {
     while ((result= cur_quick->get_next()) == HA_ERR_END_OF_FILE)
@@ -8190,10 +8200,7 @@ int QUICK_INDEX_MERGE_SELECT::read_keys_and_merge()
       if (cur_quick->file->inited != handler::NONE) 
         cur_quick->file->ha_index_end();
       if (cur_quick->init() || cur_quick->reset())
-      {
-        delete unique;
-        DBUG_RETURN(1);
-      }
+        goto err;
     }
 
     if (result)
@@ -8201,29 +8208,21 @@ int QUICK_INDEX_MERGE_SELECT::read_keys_and_merge()
       if (result != HA_ERR_END_OF_FILE)
       {
         cur_quick->range_end();
-        delete unique;
-        DBUG_RETURN(result);
+        goto err;
       }
       break;
     }
 
     if (thd->killed)
-    {
-      delete unique;
-      DBUG_RETURN(1);
-    }
+      goto err;
 
     /* skip row if it will be retrieved by clustered PK scan */
     if (pk_quick_select && pk_quick_select->row_in_ranges())
       continue;
 
     cur_quick->file->position(cur_quick->record);
-    result= unique->unique_add((char*)cur_quick->file->ref);
-    if (result)
-    {
-      delete unique;
-      DBUG_RETURN(1);
-    }
+    if (unique->unique_add((char*)cur_quick->file->ref))
+      goto err;
   }
 
   /*
@@ -8234,10 +8233,17 @@ int QUICK_INDEX_MERGE_SELECT::read_keys_and_merge()
   result= unique->get(head);
   delete unique;
   doing_pk_scan= FALSE;
-  /* index_merge currently doesn't support "using index" at all */
-  head->set_keyread(FALSE);
+  /*
+    index_merge currently doesn't support "using index" at all
+  */
+  head->disable_keyread();
   init_read_record(&read_record, thd, head, (SQL_SELECT*) 0, 1 , 1, TRUE);
   DBUG_RETURN(result);
+
+err:
+  delete unique;
+  head->disable_keyread();
+  DBUG_RETURN(1);
 }
 
 
@@ -10308,7 +10314,7 @@ QUICK_GROUP_MIN_MAX_SELECT(TABLE *table, JOIN *join_arg, bool have_min_arg,
   :join(join_arg), index_info(index_info_arg),
    group_prefix_len(group_prefix_len_arg),
    group_key_parts(group_key_parts_arg), have_min(have_min_arg),
-   have_max(have_max_arg), seen_first_key(FALSE),
+   have_max(have_max_arg), seen_first_key(FALSE), doing_key_read(FALSE),
    min_max_arg_part(min_max_arg_part_arg), key_infix(key_infix_arg),
    key_infix_len(key_infix_len_arg), min_functions_it(NULL),
    max_functions_it(NULL)
@@ -10439,7 +10445,12 @@ QUICK_GROUP_MIN_MAX_SELECT::~QUICK_GROUP_MIN_MAX_SELECT()
 {
   DBUG_ENTER("QUICK_GROUP_MIN_MAX_SELECT::~QUICK_GROUP_MIN_MAX_SELECT");
   if (file->inited != handler::NONE) 
+  {
+    DBUG_ASSERT(file == head->file);
+    if (doing_key_read)
+      head->disable_keyread();
     file->ha_index_end();
+  }
   if (min_max_arg_part)
     delete_dynamic(&min_max_ranges);
   free_root(&alloc,MYF(0));
@@ -10622,7 +10633,11 @@ int QUICK_GROUP_MIN_MAX_SELECT::reset(void)
   int result;
   DBUG_ENTER("QUICK_GROUP_MIN_MAX_SELECT::reset");
 
-  head->set_keyread(TRUE); /* We need only the key attributes */
+  if (!head->key_read)
+  {
+    doing_key_read= 1;
+    head->enable_keyread(); /* We need only the key attributes */
+  }
   if ((result= file->ha_index_init(index,1)))
     DBUG_RETURN(result);
   if (quick_prefix_select && quick_prefix_select->reset())
diff --git a/sql/opt_range.h b/sql/opt_range.h
index 6a0234e62fe..ad2eddba4f0 100644
--- a/sql/opt_range.h
+++ b/sql/opt_range.h
@@ -280,6 +280,8 @@ class QUICK_RANGE_SELECT : public QUICK_SELECT_I
 {
 protected:
   bool next,dont_free,in_ror_merged_scan;
+  /* true if we enabled key only reads */
+  bool doing_key_read;
 public:
   int error;
 protected:
@@ -623,6 +625,8 @@ private:
   bool have_min;         /* Specify whether we are computing */
   bool have_max;         /*   a MIN, a MAX, or both.         */
   bool seen_first_key;   /* Denotes whether the first key was retrieved.*/
+  bool doing_key_read;   /* true if we enabled key only reads */
+
   KEY_PART_INFO *min_max_arg_part; /* The keypart of the only argument field */
                                    /* of all MIN/MAX functions.              */
   uint min_max_arg_len;  /* The length of the MIN/MAX argument field */
diff --git a/sql/opt_sum.cc b/sql/opt_sum.cc
index 58906c7acab..2bd757ee201 100644
--- a/sql/opt_sum.cc
+++ b/sql/opt_sum.cc
@@ -326,7 +326,7 @@ int opt_sum_query(TABLE_LIST *tables, List<Item> &all_fields,COND *conds)
 	  if (!error && reckey_in_range(0, &ref, item_field->field, 
 			                conds, range_fl, prefix_len))
 	    error= HA_ERR_KEY_NOT_FOUND;
-          table->set_keyread(FALSE);
+          table->disable_keyread();
           table->file->ha_index_end();
           if (error)
 	  {
@@ -409,7 +409,7 @@ int opt_sum_query(TABLE_LIST *tables, List<Item> &all_fields,COND *conds)
 	  if (!error && reckey_in_range(1, &ref, item_field->field,
 			                conds, range_fl, prefix_len))
 	    error= HA_ERR_KEY_NOT_FOUND;
-          table->set_keyread(FALSE);
+          table->disable_keyread();
           table->file->ha_index_end();
           if (error)
           {
@@ -902,7 +902,7 @@ static bool find_key_for_maxmin(bool max_fl, TABLE_REF *ref,
             converted (for example to upper case)
           */
           if (field->part_of_key.is_set(idx))
-            table->set_keyread(TRUE);
+            table->enable_keyread();
           return 1;
         }
       }
diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index 90a7c66e0d0..f9838c26cb5 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -744,6 +744,7 @@ public:
   {
     return master_unit()->return_after_parsing();
   }
+  inline bool is_subquery_function() { return master_unit()->item != 0; }
 
   void mark_as_dependent(st_select_lex *last, Item *dependency);
 
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 7d62a3808eb..3548fbf5da3 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -1,4 +1,5 @@
 /* Copyright (c) 2000, 2010 Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2009-2010 Monty Program Ab
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -6760,7 +6761,7 @@ make_join_readinfo(JOIN *join, ulonglong options)
     case JT_CONST:				// Only happens with left join
       if (table->covering_keys.is_set(tab->ref.key) &&
 	  !table->no_keyread)
-        table->set_keyread(TRUE);
+        table->enable_keyread();
       break;
     case JT_ALL:
       /*
@@ -6827,7 +6828,7 @@ make_join_readinfo(JOIN *join, ulonglong options)
 	  if (tab->select && tab->select->quick &&
               tab->select->quick->index != MAX_KEY && //not index_merge
 	      table->covering_keys.is_set(tab->select->quick->index))
-            table->set_keyread(TRUE);
+            table->enable_keyread();
 	  else if (!table->covering_keys.is_clear_all() &&
 		   !(tab->select && tab->select->quick))
 	  {					// Only read index tree
@@ -6911,7 +6912,7 @@ void JOIN_TAB::cleanup()
   limit= 0;
   if (table)
   {
-    table->set_keyread(FALSE);
+    table->disable_keyread();
     table->file->ha_index_or_rnd_end();
     /*
       We need to reset this for next select
@@ -8275,6 +8276,8 @@ static Item *eliminate_item_equal(COND *cond, COND_EQUAL *upper_levels,
   Item *item_const= item_equal->get_const();
   Item_equal_iterator it(*item_equal);
   Item *head;
+  DBUG_ASSERT(!cond || cond->type() == Item::COND_ITEM);
+
   if (item_const)
     head= item_const;
   else
@@ -8310,27 +8313,30 @@ static Item *eliminate_item_equal(COND *cond, COND_EQUAL *upper_levels,
         return 0;
       eq_item->set_cmp_func();
       eq_item->quick_fix_field();
-   }
+    }
   }
 
-  if (!cond && !eq_list.head())
+  if (!cond)
   {
-    if (!eq_item)
-      return new Item_int((longlong) 1,1);
-    return eq_item;
-  }
-
-  if (eq_item)
+    if (eq_list.is_empty())
+    {
+      if (eq_item)
+        return eq_item;
+      return new Item_int((longlong) 1, 1);
+    }
+    /* eq_item is always set if list is not empty */
+    DBUG_ASSERT(eq_item);
     eq_list.push_back(eq_item);
-  if (!cond)
-    cond= new Item_cond_and(eq_list);
+    if (!(cond= new Item_cond_and(eq_list)))
+      return 0;                                 // Error
+  }
   else
   {
-    DBUG_ASSERT(cond->type() == Item::COND_ITEM);
-    if (eq_list.elements)
+    if (eq_item)
+      eq_list.push_back(eq_item);
+    if (!eq_list.is_empty())
       ((Item_cond *) cond)->add_at_head(&eq_list);
   }
-
   cond->quick_fix_field();
   cond->update_used_tables();
    
@@ -8371,6 +8377,7 @@ static COND* substitute_for_best_equal_field(COND *cond,
                                              void *table_join_idx)
 {
   Item_equal *item_equal;
+  COND *org_cond= cond;                 // Return this in case of fatal error
 
   if (cond->type() == Item::COND_ITEM)
   {
@@ -8394,7 +8401,7 @@ static COND* substitute_for_best_equal_field(COND *cond,
     Item *item;
     while ((item= li++))
     {
-      Item *new_item =substitute_for_best_equal_field(item, cond_equal,
+      Item *new_item= substitute_for_best_equal_field(item, cond_equal,
                                                       table_join_idx);
       /*
         This works OK with PS/SP re-execution as changes are made to
@@ -8413,6 +8420,8 @@ static COND* substitute_for_best_equal_field(COND *cond,
         // This occurs when eliminate_item_equal() founds that cond is
         // always false and substitutes it with Item_int 0.
         // Due to this, value of item_equal will be 0, so just return it.
+        if (!cond)
+          return org_cond;                      // Error
         if (cond->type() != Item::COND_ITEM)
           break;
       }
@@ -8429,7 +8438,8 @@ static COND* substitute_for_best_equal_field(COND *cond,
     item_equal->sort(&compare_fields_by_table_order, table_join_idx);
     if (cond_equal && cond_equal->current_level.head() == item_equal)
       cond_equal= 0;
-    return eliminate_item_equal(0, cond_equal, item_equal);
+    cond= eliminate_item_equal(0, cond_equal, item_equal);
+    return cond ? cond : org_cond;
   }
   else
     cond->transform(&Item::replace_equal_field, 0);
@@ -11981,11 +11991,11 @@ join_read_const_table(JOIN_TAB *tab, POSITION *pos)
 	!table->no_keyread &&
         (int) table->reginfo.lock_type <= (int) TL_READ_HIGH_PRIORITY)
     {
-      table->set_keyread(TRUE);
+      table->enable_keyread();
       tab->index= tab->ref.key;
     }
     error=join_read_const(tab);
-    table->set_keyread(FALSE);
+    table->disable_keyread();
     if (error)
     {
       tab->info="unique row not found";
@@ -12367,8 +12377,9 @@ join_read_first(JOIN_TAB *tab)
 {
   int error= 0;
   TABLE *table=tab->table;
-  if (table->covering_keys.is_set(tab->index) && !table->no_keyread)
-    table->set_keyread(TRUE);
+  if (table->covering_keys.is_set(tab->index) && !table->no_keyread &&
+      !table->key_read)
+    table->enable_keyread();
   tab->table->status=0;
   tab->read_record.read_record=join_read_next;
   tab->read_record.table=table;
@@ -12404,8 +12415,9 @@ join_read_last(JOIN_TAB *tab)
 {
   TABLE *table=tab->table;
   int error= 0;
-  if (table->covering_keys.is_set(tab->index) && !table->no_keyread)
-    table->set_keyread(TRUE);
+  if (table->covering_keys.is_set(tab->index) && !table->no_keyread &&
+      !table->key_read)
+    table->enable_keyread();
   tab->table->status=0;
   tab->read_record.read_record=join_read_prev;
   tab->read_record.table=table;
@@ -13868,7 +13880,7 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
            and best_key doesn't, then revert the decision.
         */
         if (!table->covering_keys.is_set(best_key))
-          table->set_keyread(FALSE);
+          table->disable_keyread();
         if (!quick_created)
 	{
           tab->index= best_key;
@@ -13880,8 +13892,8 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
             delete select->quick;
             select->quick= 0;
           }
-          if (table->covering_keys.is_set(best_key))
-            table->set_keyread(TRUE);
+          if (table->covering_keys.is_set(best_key) && ! table->key_read)
+            table->enable_keyread();
           table->file->ha_index_or_rnd_end();
           if (join->select_options & SELECT_DESCRIBE)
           {
@@ -14056,7 +14068,7 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order,
         and in index_merge 'Only index' cannot be used
       */
       if (((uint) tab->ref.key != select->quick->index))
-        table->set_keyread(FALSE);
+        table->disable_keyread();
     }
     else
     {
@@ -14112,7 +14124,7 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order,
   tab->type=JT_ALL;				// Read with normal read_record
   tab->read_first_record= join_init_read_record;
   tab->join->examined_rows+=examined_rows;
-  table->set_keyread(FALSE); // Restore if we used indexes
+  table->disable_keyread(); // Restore if we used indexes
   DBUG_RETURN(table->sort.found_records == HA_POS_ERROR);
 err:
   DBUG_RETURN(-1);
@@ -14657,12 +14669,15 @@ store_record_in_cache(JOIN_CACHE *cache)
       {
 	uchar *str,*end;
         Field *field= copy->field;
-        if (field && field->maybe_null() && field->is_null())
+        if (field && field->is_null())
           end= str= copy->str;
         else
+        {
           for (str=copy->str,end= str+copy->length;
                end > str && end[-1] == ' ' ;
-               end--) ;
+               end--)
+            ;
+        }
 	length=(uint) (end-str);
 	memcpy(pos+2, str, length);
         int2store(pos, length);
@@ -17342,7 +17357,7 @@ void st_select_lex::print(THD *thd, String *str, enum_query_type query_type)
     else
       str->append(',');
 
-    if (master_unit()->item && item->is_autogenerated_name)
+    if (is_subquery_function() && item->is_autogenerated_name)
     {
       /*
         Do not print auto-generated aliases in subqueries. It has no purpose
diff --git a/sql/sql_update.cc b/sql/sql_update.cc
index 1d1f9dedf22..d90480732cd 100644
--- a/sql/sql_update.cc
+++ b/sql/sql_update.cc
@@ -841,7 +841,7 @@ int mysql_update(THD *thd,
 err:
   delete select;
   free_underlaid_joins(thd, select_lex);
-  table->set_keyread(FALSE);
+  table->disable_keyread();
   thd->abort_on_warning= 0;
   DBUG_RETURN(1);
 }
diff --git a/sql/table.cc b/sql/table.cc
index 7bfdc8d184e..0c3b863786a 100644
--- a/sql/table.cc
+++ b/sql/table.cc
@@ -4395,7 +4395,7 @@ void st_table::mark_columns_used_by_index(uint index)
   MY_BITMAP *bitmap= &tmp_set;
   DBUG_ENTER("st_table::mark_columns_used_by_index");
 
-  set_keyread(TRUE);
+  enable_keyread();
   bitmap_clear_all(bitmap);
   mark_columns_used_by_index_no_reset(index, bitmap);
   column_bitmaps_set(bitmap, bitmap);
@@ -4418,7 +4418,7 @@ void st_table::restore_column_maps_after_mark_index()
 {
   DBUG_ENTER("st_table::restore_column_maps_after_mark_index");
 
-  set_keyread(FALSE);
+  disable_keyread();
   default_column_bitmaps();
   file->column_bitmaps_signal();
   DBUG_VOID_RETURN;
diff --git a/sql/table.h b/sql/table.h
index e43e6e5950f..8588f3c94c3 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -905,19 +905,23 @@ struct st_table {
   inline bool needs_reopen_or_name_lock()
   { return s->version != refresh_version; }
   bool is_children_attached(void);
-  inline void set_keyread(bool flag)
+  inline void enable_keyread()
   {
-    DBUG_ASSERT(file);
-    if (flag && !key_read)
-    {
-      key_read= 1;
-      file->extra(HA_EXTRA_KEYREAD);
-    }
-    else if (!flag && key_read)
+    DBUG_ENTER("enable_keyread");
+    DBUG_ASSERT(key_read == 0);
+    key_read= 1;
+    file->extra(HA_EXTRA_KEYREAD);
+    DBUG_VOID_RETURN;
+  }
+  inline void disable_keyread()
+  {
+    DBUG_ENTER("disable_keyread");
+    if (key_read)
     {
       key_read= 0;
       file->extra(HA_EXTRA_NO_KEYREAD);
     }
+    DBUG_VOID_RETURN;
   }
 };