Auto merge

3 files changed, 226 insertions, 0 deletions

diff --git a/sql/sql_cache.cc b/sql/sql_cache.cc
index b55fa148e24..4a060ba7178 100644
--- a/sql/sql_cache.cc
+++ b/sql/sql_cache.cc
@@ -363,6 +363,43 @@ TYPELIB query_cache_type_typelib=
   array_elements(query_cache_type_names)-1,"", query_cache_type_names, NULL
 };
 
+
+/**
+  Helper function for determine if a SELECT statement has a SQL_NO_CACHE
+  directive.
+  
+  @param sql A pointer to the first white space character after SELECT
+  
+  @return
+   @retval TRUE The character string contains SQL_NO_CACHE
+   @retval FALSE No directive found.
+*/
+ 
+static bool has_no_cache_directive(char *sql)
+{
+  int i=0;
+  while (sql[i] == ' ')
+    ++i;
+    
+  if (my_toupper(system_charset_info, sql[i])    == 'S' &&
+      my_toupper(system_charset_info, sql[i+1])  == 'Q' &&
+      my_toupper(system_charset_info, sql[i+2])  == 'L' &&
+      my_toupper(system_charset_info, sql[i+3])  == '_' &&
+      my_toupper(system_charset_info, sql[i+4])  == 'N' &&
+      my_toupper(system_charset_info, sql[i+5])  == 'O' &&
+      my_toupper(system_charset_info, sql[i+6])  == '_' &&
+      my_toupper(system_charset_info, sql[i+7])  == 'C' &&
+      my_toupper(system_charset_info, sql[i+8])  == 'A' &&
+      my_toupper(system_charset_info, sql[i+9])  == 'C' &&
+      my_toupper(system_charset_info, sql[i+10]) == 'H' &&
+      my_toupper(system_charset_info, sql[i+11]) == 'E' &&
+      my_toupper(system_charset_info, sql[i+12]) == ' ')
+    return TRUE;
+  
+  return FALSE;       
+}
+
+
 /*****************************************************************************
  Query_cache_block_table method(s)
 *****************************************************************************/
@@ -1095,6 +1132,16 @@ Query_cache::send_result_to_client(THD *thd, char *sql, uint query_length)
       DBUG_PRINT("qcache", ("The statement is not a SELECT; Not cached"));
       goto err;
     }
+    
+    if (query_length > 20 && has_no_cache_directive(&sql[i+6]))
+    {
+      /*
+        We do not increase 'refused' statistics here since it will be done
+        later when the query is parsed.
+      */
+      DBUG_PRINT("qcache", ("The statement has a SQL_NO_CACHE directive"));
+      goto err;
+    }
   }
 
 #ifdef __WIN__
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 4ea621f428d..88b7dfb46d7 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -343,6 +343,12 @@ void THD::init(void)
   if (variables.sql_mode & MODE_NO_BACKSLASH_ESCAPES)
     server_status|= SERVER_STATUS_NO_BACKSLASH_ESCAPES;
   options= thd_startup_options;
+
+  if (variables.max_join_size == HA_POS_ERROR)
+    options |= OPTION_BIG_SELECTS;
+  else
+    options &= ~OPTION_BIG_SELECTS;
+
   transaction.all.modified_non_trans_table= transaction.stmt.modified_non_trans_table= FALSE;
   open_options=ha_open_options;
   update_lock_default= (variables.low_priority_updates ?
diff --git a/tests/mysql_client_test.c b/tests/mysql_client_test.c
index 7df84c600c9..32c39b149d4 100644
--- a/tests/mysql_client_test.c
+++ b/tests/mysql_client_test.c
@@ -115,6 +115,8 @@ static void client_disconnect(void);
 
 #define DIE_UNLESS(expr) \
         ((void) ((expr) ? 0 : (die(__FILE__, __LINE__, #expr), 0)))
+#define DIE_IF(expr) \
+        ((void) ((expr) ? (die(__FILE__, __LINE__, #expr), 0) : 0))
 #define DIE(expr) \
         die(__FILE__, __LINE__, #expr)
 
@@ -16276,6 +16278,176 @@ static void test_bug38486(void)
   DBUG_VOID_RETURN;
 }
 
+static void bug20023_change_user(MYSQL *con)
+{
+  DIE_IF(mysql_change_user(con,
+                           opt_user,
+                           opt_password,
+                           opt_db ? opt_db : "test"));
+}
+
+static void bug20023_query_int_variable(MYSQL *con,
+                                        const char *var_name,
+                                        int *var_value)
+{
+  MYSQL_RES *rs;
+  MYSQL_ROW row;
+
+  char query_buffer[MAX_TEST_QUERY_LENGTH];
+
+  my_snprintf(query_buffer,
+          sizeof (query_buffer),
+          "SELECT @@%s",
+          (const char *) var_name);
+
+  DIE_IF(mysql_query(con, query_buffer));
+  DIE_UNLESS(rs= mysql_store_result(con));
+  DIE_UNLESS(row= mysql_fetch_row(rs));
+  *var_value= atoi(row[0]);
+  mysql_free_result(rs);
+}
+
+static void test_bug20023()
+{
+  MYSQL con;
+
+  int sql_big_selects_orig;
+  int max_join_size_orig;
+
+  int sql_big_selects_2;
+  int sql_big_selects_3;
+  int sql_big_selects_4;
+  int sql_big_selects_5;
+
+  char query_buffer[MAX_TEST_QUERY_LENGTH];
+
+  /* Create a new connection. */
+
+  DIE_UNLESS(mysql_init(&con));
+
+  DIE_UNLESS(mysql_real_connect(&con,
+                                opt_host,
+                                opt_user,
+                                opt_password,
+                                opt_db ? opt_db : "test",
+                                opt_port,
+                                opt_unix_socket,
+                                CLIENT_FOUND_ROWS));
+
+  /***********************************************************************
+   Remember original SQL_BIG_SELECTS, MAX_JOIN_SIZE values.
+  ***********************************************************************/
+
+  bug20023_query_int_variable(&con,
+                              "session.sql_big_selects",
+                              &sql_big_selects_orig);
+
+  bug20023_query_int_variable(&con,
+                              "global.max_join_size",
+                              &max_join_size_orig);
+
+  /***********************************************************************
+   Test that COM_CHANGE_USER resets the SQL_BIG_SELECTS to the initial value.
+  ***********************************************************************/
+
+  /* Issue COM_CHANGE_USER. */
+
+  bug20023_change_user(&con);
+
+  /* Query SQL_BIG_SELECTS. */
+
+  bug20023_query_int_variable(&con,
+                              "session.sql_big_selects",
+                              &sql_big_selects_2);
+
+  /* Check that SQL_BIG_SELECTS is reset properly. */
+
+  DIE_UNLESS(sql_big_selects_orig == sql_big_selects_2);
+
+  /***********************************************************************
+   Test that if MAX_JOIN_SIZE set to non-default value,
+   SQL_BIG_SELECTS will be 0.
+  ***********************************************************************/
+
+  /* Set MAX_JOIN_SIZE to some non-default value. */
+
+  DIE_IF(mysql_query(&con, "SET @@global.max_join_size = 10000"));
+  DIE_IF(mysql_query(&con, "SET @@session.max_join_size = default"));
+
+  /* Issue COM_CHANGE_USER. */
+
+  bug20023_change_user(&con);
+
+  /* Query SQL_BIG_SELECTS. */
+
+  bug20023_query_int_variable(&con,
+                              "session.sql_big_selects",
+                              &sql_big_selects_3);
+
+  /* Check that SQL_BIG_SELECTS is 0. */
+
+  DIE_UNLESS(sql_big_selects_3 == 0);
+
+  /***********************************************************************
+   Test that if MAX_JOIN_SIZE set to default value,
+   SQL_BIG_SELECTS will be 1.
+  ***********************************************************************/
+
+  /* Set MAX_JOIN_SIZE to the default value (-1). */
+
+  DIE_IF(mysql_query(&con, "SET @@global.max_join_size = -1"));
+  DIE_IF(mysql_query(&con, "SET @@session.max_join_size = default"));
+
+  /* Issue COM_CHANGE_USER. */
+
+  bug20023_change_user(&con);
+
+  /* Query SQL_BIG_SELECTS. */
+
+  bug20023_query_int_variable(&con,
+                              "session.sql_big_selects",
+                              &sql_big_selects_4);
+
+  /* Check that SQL_BIG_SELECTS is 1. */
+
+  DIE_UNLESS(sql_big_selects_4 == 1);
+
+  /***********************************************************************
+   Restore MAX_JOIN_SIZE.
+   Check that SQL_BIG_SELECTS will be the original one.
+  ***********************************************************************/
+
+  /* Restore MAX_JOIN_SIZE. */
+
+  my_snprintf(query_buffer,
+           sizeof (query_buffer),
+           "SET @@global.max_join_size = %d",
+           (int) max_join_size_orig);
+
+  DIE_IF(mysql_query(&con, query_buffer));
+  DIE_IF(mysql_query(&con, "SET @@session.max_join_size = default"));
+
+  /* Issue COM_CHANGE_USER. */
+
+  bug20023_change_user(&con);
+
+  /* Query SQL_BIG_SELECTS. */
+
+  bug20023_query_int_variable(&con,
+                              "session.sql_big_selects",
+                              &sql_big_selects_5);
+
+  /* Check that SQL_BIG_SELECTS is 1. */
+
+  DIE_UNLESS(sql_big_selects_5 == sql_big_selects_orig);
+
+  /***********************************************************************
+   That's it. Cleanup.
+  ***********************************************************************/
+
+  mysql_close(&con);
+}
+
 static void test_bug40365(void)
 {
   uint         rc, i;
@@ -16780,6 +16952,7 @@ static struct my_tests_st my_tests[]= {
   { "test_bug36326", test_bug36326 },
 #endif
   { "test_bug41078", test_bug41078 },
+  { "test_bug20023", test_bug20023 },
   { 0, 0 }
 };