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

@@ -2602,32 +2602,31 @@ 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)
+  /*
+    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
-  /* 
-     We don't care about in case of an error below because current_db
-     was just set to 0.
+  /*  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.
   */
   if (!mysql_query(&mysql, "SELECT DATABASE()") &&
       (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
+    (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 @@ Default database: '%s'. Query: '%s'",
   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 @@ log space");
 		  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 @@ static long mysql_rm_known_files(THD *thd, MY_DIR *dirp, const char *db,
     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)))
     {