BUG #28421 Infinite loop on slave relay logs

Manually deleteing one or more entries from 'master-bin.index', will
cause master infinitely loop to send one binlog file. 

When starting a dump session, master opens index file and search the binlog file
which is being requested by the slave. The position of the binlog file in the
index file is recorded. it will be used to find the next binlog file when current
binlog file has dumped completely. As only the position is used, it may
not get the correct file if some entries has been removed manually from the index file.
the master will reopen the current binlog file which has been dump completely
and redump it if it can not get the next binlog file's name from index file.
It obviously is a logical error.


Even though it is allowed to manually change index file,
but it is not recommended. so after this patch, master
sends a fatal error to slave and close the dump session if a new binlog file
has been generated and master can not get it from the index file.

mysql-test/include/truncate_file.inc

+# truncate a giving file, all contents of the file are be cleared
+
+if (`SELECT 'x$file' = 'x'`)
+{
+  --echo Please assign a file name to $file!!
+  exit;
+}
+
+let TRUNCATE_FILE= $file;
+
+perl;
+use Env;
+Env::import('TRUNCATE_FILE');
+open FILE, '>', $TRUNCATE_FILE || die "Can not open file $file";
+close FILE;
+EOF

mysql-test/suite/rpl/r/rpl_manual_change_index_file.result

+stop slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+reset master;
+reset slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+start slave;
+FLUSH LOGS;
+CREATE TABLE t1(c1 INT);
+FLUSH LOGS;
+call mtr.add_suppression('Got fatal error 1236 from master when reading data from binary log: .*could not find next log');
+Last_IO_Error
+Got fatal error 1236 from master when reading data from binary log: 'could not find next log'
+CREATE TABLE t2(c1 INT);
+FLUSH LOGS;
+CREATE TABLE t3(c1 INT);
+FLUSH LOGS;
+CREATE TABLE t4(c1 INT);
+START SLAVE IO_THREAD;
+SHOW TABLES;
+Tables_in_test
+t1
+t2
+t3
+t4
+DROP TABLE t1, t2, t3, t4;

mysql-test/suite/rpl/t/rpl_manual_change_index_file.test

+source include/master-slave.inc;
+
+#
+# BUG#28421 Infinite loop on slave relay logs
+# 
+# That, manually deleteing one or more entries from 'master-bin.index', will
+# cause master infinitely loop to send one binlog file.
+# 
+# Manually changing index file is a illegal action, so when this happen, we
+# send a fatal error to slave and close the dump session.
+
+FLUSH LOGS;
+# Now, 2 entries in index file.
+# ./master-bin.000001
+# ./master-bin.000002
+
+CREATE TABLE t1(c1 INT);
+# Now, the current dump file(master-bin.000002) is the second line of index
+# file
+sync_slave_with_master;
+# Now, all events has been replicate to slave. As current dump file
+# (master-bin.000002) is the last binlog file, so master is waiting for new
+# events.
+
+connection master;
+# Delete './master-bin.000001' from index file.
+let $MYSQLD_DATADIR= `SELECT @@DATADIR`;
+#remove_file $MYSQLD_DATADIR/master-bin.index;
+let $file= $MYSQLD_DATADIR/master-bin.index;
+source include/truncate_file.inc;
+
+if (`SELECT CONVERT(@@VERSION_COMPILE_OS USING latin1) NOT IN ('Win32', 'Win64', 'Windows')`)
+{
+append_file $MYSQLD_DATADIR/master-bin.index;
+./master-bin.000002
+EOF
+sleep 0.00000001;
+}
+
+if (`SELECT CONVERT(@@VERSION_COMPILE_OS USING latin1) IN ('Win32', 'Win64', 'Windows')`)
+{
+append_file $MYSQLD_DATADIR/master-bin.index;
+.\master-bin.000002
+EOF
+sleep 0.00000001;
+}
+
+# Now, only 1 entry in index file.
+# ./master-bin.000002
+
+# Generate master-bin.000003, but it is in the second line.
+FLUSH LOGS;
+# Now, 2 entries in index file.
+# ./master-bin.000002
+# ./master-bin.000003
+
+# Now, master know that new binlog file(master-bin.000003) has been generated.
+# It expects that the new binlog file is in third line of index file, but
+# there is no third line in index file. It is so strange that master sends an
+# error to slave. 
+call mtr.add_suppression('Got fatal error 1236 from master when reading data from binary log: .*could not find next log');
+connection slave;
+source include/wait_for_slave_io_to_stop.inc;
+let $last_error= query_get_value(SHOW SLAVE STATUS, Last_IO_Error, 1);
+echo Last_IO_Error;
+echo $last_error;
+
+connection master;
+CREATE TABLE t2(c1 INT);
+FLUSH LOGS;
+CREATE TABLE t3(c1 INT);
+FLUSH LOGS;
+CREATE TABLE t4(c1 INT);
+
+connection slave;
+START SLAVE IO_THREAD;
+source include/wait_for_slave_io_to_start.inc;
+
+connection master;
+sync_slave_with_master;
+SHOW TABLES;
+
+connection master;
+DROP TABLE t1, t2, t3, t4;
+source include/master-slave-end.inc;

sql/sql_repl.cc

@@ -711,11 +711,14 @@ impossible position";
 
       thd_proc_info(thd, "Finished reading one binlog; switching to next binlog");
       switch (mysql_bin_log.find_next_log(&linfo, 1)) {
-      case LOG_INFO_EOF:
-	loop_breaker = (flags & BINLOG_DUMP_NON_BLOCK);
-	break;
       case 0:
 	break;
+      case LOG_INFO_EOF:
+        if (mysql_bin_log.is_active(log_file_name))
+        {
+          loop_breaker = (flags & BINLOG_DUMP_NON_BLOCK);
+          break;
+        }
       default:
 	errmsg = "could not find next log";
 	my_errno= ER_MASTER_FATAL_ERROR_READING_BINLOG;