merged

mysql-test/r/rpl_set_charset.result:
  Auto merged
mysql-test/r/select.result:
  Auto merged
mysql-test/t/rpl_set_charset.test:
  Auto merged
mysql-test/t/select.test:
  Auto merged
sql/slave.cc:
  Auto merged

client/mysql.cc

@@ -2602,13 +2602,14 @@ com_use(String *buffer __attribute__((unused)), char *line)
     put_info("USE must be followed by a database name", INFO_ERROR);
     return 0;
   }
-
   /*
     We need to recheck the current database, because it may change
     under our feet, for example if DROP DATABASE or RENAME DATABASE
     (latter one not yet available by the time the comment was written)
   */
-  current_db= 0; // Let's reset current_db, assume it's gone
+  /*  Let's reset current_db, assume it's gone */
+  my_free(current_db, MYF(MY_ALLOW_ZERO_PTR));
+  current_db= 0;
   /*
     We don't care about in case of an error below because current_db
     was just set to 0.
@@ -2617,17 +2618,15 @@ com_use(String *buffer __attribute__((unused)), char *line)
       (res= mysql_use_result(&mysql)))
   {
     row= mysql_fetch_row(res);
-    if (row[0] &&
-	(!current_db || cmp_database(charset_info, current_db, row[0])))
+    if (row[0])
     {
-      my_free(current_db, MYF(MY_ALLOW_ZERO_PTR));
       current_db= my_strdup(row[0], MYF(MY_WME));
     }
     (void) mysql_fetch_row(res);               // Read eof
     mysql_free_result(res);
   }
 
-  if (!current_db || cmp_database(charset_info, current_db, tmp))
+  if (!current_db || cmp_database(current_db,tmp))
   {
     if (one_database)
       skip_updates= 1;

mysql-test/r/rpl_set_charset.result

@@ -45,5 +45,4 @@ C0C1C2C3C4C5C6C7C8C9CACBCCCDCECF	C0
 D0D1D2D3D4D5D6D7D8D9DADBDCDDDEDF	D0
 E0E1E2E3E4E5E6E7E8E9EAEBECEDEEEF	E0
 F0F1F2F3F4F5F6F7F8F9FAFBFCFDFEFF	F0
-drop table t1;
 drop database mysqltest1;

mysql-test/r/select.result

@@ -2348,3 +2348,19 @@ select * from t2,t3 where t2.s = t3.s;
 s	s
 two		two	
 drop table t1, t2, t3;
+CREATE TABLE t1 (
+i int(11) NOT NULL default '0',
+c char(10) NOT NULL default '',
+PRIMARY KEY  (i),
+UNIQUE KEY c (c)
+) TYPE=MyISAM;
+INSERT INTO t1 VALUES (1,'a');
+INSERT INTO t1 VALUES (2,'b');
+INSERT INTO t1 VALUES (3,'c');
+EXPLAIN SELECT i FROM t1 WHERE i=1;
+table	type	possible_keys	key	key_len	ref	rows	Extra
+t1	const	PRIMARY	PRIMARY	4	const	1	Using index
+EXPLAIN SELECT i FROM t1 WHERE i=1;
+table	type	possible_keys	key	key_len	ref	rows	Extra
+t1	const	PRIMARY	PRIMARY	4	const	1	Using index
+DROP TABLE t1;

mysql-test/t/rpl_set_charset.test

@@ -27,9 +27,7 @@ use mysqltest1;
 select "--- on slave ---";
 select hex(a),b from t1 order by b;
 connection master;
-drop table t1;
+drop database mysqltest1;
 save_master_pos;
 connection slave;
 sync_with_master;
-connection master;
-drop database mysqltest1;

mysql-test/t/select.test

@@ -1880,3 +1880,24 @@ select * from t3 where s = 'one';
 select * from t1,t2 where t1.s = t2.s;
 select * from t2,t3 where t2.s = t3.s;
 drop table t1, t2, t3;
+
+#
+# Covering index is mentioned in EXPLAIN output for const tables (bug #5333)
+#
+
+CREATE TABLE t1 (
+  i int(11) NOT NULL default '0',
+  c char(10) NOT NULL default '',
+  PRIMARY KEY  (i),
+  UNIQUE KEY c (c)
+) TYPE=MyISAM;
+
+INSERT INTO t1 VALUES (1,'a');
+INSERT INTO t1 VALUES (2,'b');
+INSERT INTO t1 VALUES (3,'c');
+
+EXPLAIN SELECT i FROM t1 WHERE i=1;
+
+EXPLAIN SELECT i FROM t1 WHERE i=1;
+
+DROP TABLE t1;

sql/log_event.cc

@@ -977,7 +977,7 @@ void Query_log_event::print(FILE* file, bool short_form, char* last_db)
 int Query_log_event::exec_event(struct st_relay_log_info* rli)
 {
   int expected_error,actual_error= 0;
-  thd->db= (char*) rewrite_db(db);
+  thd->db= (char*) rewrite_db(db); // thd->db_length is set later if needed
 
   /*
     InnoDB internally stores the master log position it has processed so far;
@@ -995,6 +995,11 @@ int Query_log_event::exec_event(struct st_relay_log_info* rli)
   if (db_ok(thd->db, replicate_do_db, replicate_ignore_db))
   {
     thd->set_time((time_t)when);
+    /*
+      We cannot use db_len from event to fill thd->db_length, because
+      rewrite_db() may have changed db.
+    */ 
+    thd->db_length= thd->db ? strlen(thd->db) : 0;
     thd->query_length= q_len;
     thd->query = (char*)query;
     VOID(pthread_mutex_lock(&LOCK_thread_count));
@@ -1082,7 +1087,7 @@ end:
   VOID(pthread_mutex_lock(&LOCK_thread_count));
   thd->db= 0;	                        // prevent db from being freed
   thd->query= 0;			// just to be sure
-  thd->query_length= 0;
+  thd->query_length= thd->db_length =0;
   VOID(pthread_mutex_unlock(&LOCK_thread_count));
   close_thread_tables(thd);      
   free_root(&thd->mem_root,MYF(MY_KEEP_PREALLOC));
@@ -1693,7 +1698,7 @@ int Load_log_event::exec_event(NET* net, struct st_relay_log_info* rli,
 			       bool use_rli_only_for_errors)
 {
   char *load_data_query= 0;
-  thd->db= (char*) rewrite_db(db);
+  thd->db= (char*) rewrite_db(db); // thd->db_length is set later if needed
   DBUG_ASSERT(thd->query == 0);
   thd->query_length= 0;                         // Should not be needed
   thd->query_error= 0;
@@ -1728,6 +1733,7 @@ int Load_log_event::exec_event(NET* net, struct st_relay_log_info* rli,
   if (db_ok(thd->db, replicate_do_db, replicate_ignore_db))
   {
     thd->set_time((time_t)when);
+    thd->db_length= thd->db ? strlen(thd->db) : 0;
     VOID(pthread_mutex_lock(&LOCK_thread_count));
     thd->query_id = query_id++;
     VOID(pthread_mutex_unlock(&LOCK_thread_count));
@@ -1854,7 +1860,7 @@ Slave: load data infile on table '%s' at log position %s in log \
   VOID(pthread_mutex_lock(&LOCK_thread_count));
   thd->db= 0;
   thd->query= 0;
-  thd->query_length= 0;
+  thd->query_length= thd->db_length= 0;
   VOID(pthread_mutex_unlock(&LOCK_thread_count));
   close_thread_tables(thd);
   if (load_data_query)

sql/slave.cc

@@ -1290,6 +1290,7 @@ be equal for replication to work";
   Used by fetch_master_table (used by LOAD TABLE tblname FROM MASTER and LOAD
   DATA FROM MASTER). Drops the table (if 'overwrite' is true) and recreates it
   from the dump. Honours replication inclusion/exclusion rules.
+  db must be non-zero (guarded by assertion).
 
   RETURN VALUES
     0           success
@@ -1300,8 +1301,8 @@ static int create_table_from_dump(THD* thd, MYSQL *mysql, const char* db,
 				  const char* table_name, bool overwrite)
 {
   ulong packet_len;
-  char *query;
-  char* save_db;
+  char *query, *save_db;
+  uint32 save_db_length;
   Vio* save_vio;
   HA_CHECK_OPT check_opt;
   TABLE_LIST tables;
@@ -1357,9 +1358,13 @@ static int create_table_from_dump(THD* thd, MYSQL *mysql, const char* db,
   thd->proc_info = "Creating table from master dump";
   // save old db in case we are creating in a different database
   save_db = thd->db;
+  save_db_length= thd->db_length;
   thd->db = (char*)db;
+  DBUG_ASSERT(thd->db);
+  thd->db_length= strlen(thd->db);
   mysql_parse(thd, thd->query, packet_len); // run create table
   thd->db = save_db;		// leave things the way the were before
+  thd->db_length= save_db_length;
   thd->options = save_options;
   
   if (thd->query_error)
@@ -3225,7 +3230,7 @@ err:
 		  IO_RPL_LOG_NAME, llstr(mi->master_log_pos,llbuff));
   VOID(pthread_mutex_lock(&LOCK_thread_count));
   thd->query = thd->db = 0; // extra safety
-  thd->query_length = 0;
+  thd->query_length= thd->db_length= 0;
   VOID(pthread_mutex_unlock(&LOCK_thread_count));
   if (mysql)
   {
@@ -3391,7 +3396,7 @@ the slave SQL thread with \"SLAVE START\". We stopped at log \
  err:
   VOID(pthread_mutex_lock(&LOCK_thread_count));
   thd->query = thd->db = 0; // extra safety
-  thd->query_length = 0;
+  thd->query_length= thd->db_length= 0;
   VOID(pthread_mutex_unlock(&LOCK_thread_count));
   thd->proc_info = "Waiting for slave mutex on exit";
   pthread_mutex_lock(&rli->run_lock);

sql/sql_db.cc

@@ -852,6 +852,11 @@ err:
     communication packet (in case of 'connect' or 'COM_INIT_DB')
     we have to do end space removal in this function.
 
+  NOTES
+    Do as little as possible in this function, as it is not called for the
+    replication slave SQL thread (for that thread, setting of thd->db is done
+    in ::exec_event() methods of log_event.cc).
+
   RETURN VALUES
     0	ok
     1	error

sql/sql_select.cc

@@ -5930,6 +5930,7 @@ join_read_const_table(JOIN_TAB *tab, POSITION *pos)
     {
       table->key_read=1;
       table->file->extra(HA_EXTRA_KEYREAD);
+      tab->index= tab->ref.key;
     }
     if ((error=join_read_const(tab)))
     {