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Always send a fake Rotate event (this is roughly 70 bytes) when starting binlog_dump.

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This way 3.23.58 slaves will always detect a 4.0.14 master (and stop)
immediately. BUG#198.
This commit is contained in:
guilhem@mysql.com 2003-06-21 18:10:59 +02:00
parent 55102bfa1a
commit 04e5a6baa9
3 changed files with 31 additions and 16 deletions
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2
mysql-test/r/rpl_log.result
View file

@ -93,6 +93,6 @@ slave-bin.002 62 Query 1 168 use test; insert into t1 values (1)
slave-bin.002 122 Query 1 228 use test; drop table t1
show slave status;
Master_Host Master_User Master_Port Connect_retry Master_Log_File Read_Master_Log_Pos Relay_Log_File Relay_Log_Pos Relay_Master_Log_File Slave_IO_Running Slave_SQL_Running Replicate_do_db Replicate_ignore_db Last_errno Last_error Skip_counter Exec_master_log_pos Relay_log_space
127.0.0.1 root MASTER_PORT 1 master-bin.002 276 slave-relay-bin.002 1522 master-bin.002 Yes Yes 0 0 276 1526
127.0.0.1 root MASTER_PORT 1 master-bin.002 276 slave-relay-bin.002 1563 master-bin.002 Yes Yes 0 0 276 1567
show binlog events in 'slave-bin.005' from 4;
Error when executing command SHOW BINLOG EVENTS: Could not find target log

2
mysql-test/r/rpl_log_pos.result
View file

@ -21,7 +21,7 @@ Master_Host Master_User Master_Port Connect_retry Master_Log_File Read_Master_Lo
slave start;
show slave status;
Master_Host Master_User Master_Port Connect_retry Master_Log_File Read_Master_Log_Pos Relay_Log_File Relay_Log_Pos Relay_Master_Log_File Slave_IO_Running Slave_SQL_Running Replicate_do_db Replicate_ignore_db Last_errno Last_error Skip_counter Exec_master_log_pos Relay_log_space
127.0.0.1 root MASTER_PORT 1 master-bin.001 73 slave-relay-bin.001 4 master-bin.001 No Yes 0 0 73 4
127.0.0.1 root MASTER_PORT 1 master-bin.001 73 slave-relay-bin.001 45 master-bin.001 No Yes 0 0 73 45
slave stop;
change master to master_log_pos=173;
slave start;

43
sql/sql_repl.cc
View file

@ -51,7 +51,7 @@ int check_binlog_magic(IO_CACHE* log, const char** errmsg)
}
static int fake_rotate_event(NET* net, String* packet, char* log_file_name,
const char**errmsg)
ulonglong position, const char**errmsg)
{
char header[LOG_EVENT_HEADER_LEN], buf[ROTATE_HEADER_LEN];
memset(header, 0, 4); // when does not matter
@ -69,7 +69,7 @@ static int fake_rotate_event(NET* net, String* packet, char* log_file_name,
packet->append(header, sizeof(header));
/* We need to split the next statement because of problem with cxx */
int4store(buf,4); // tell slave to skip magic number
int4store(buf,position);
int4store(buf+4,0);
packet->append(buf, ROTATE_HEADER_LEN);
packet->append(p,ident_len);
@ -382,17 +382,30 @@ impossible position";
*/
packet->set("\0", 1);
// if we are at the start of the log
if (pos == BIN_LOG_HEADER_SIZE)
/*
Before 4.0.14 we called fake_rotate_event below only if
(pos == BIN_LOG_HEADER_SIZE), because if this is false then the slave
already knows the binlog's name.
Now we always call fake_rotate_event; if the slave already knew the log's
name (ex: CHANGE MASTER TO MASTER_LOG_FILE=...) this is useless but does not
harm much. It is nice for 3.23 (>=.58) slaves which test Rotate events
to see if the master is 4.0 (then they choose to stop because they can't
replicate 4.0); by always calling fake_rotate_event we are sure that 3.23.58
and newer will detect the problem as soon as replication starts (BUG#198).
Always calling fake_rotate_event makes sending of normal
(=from-binlog) Rotate events a priori unneeded, but it is not so simple: the
2 Rotate events are not equivalent, the normal one is before the Stop event,
the fake one is after. If we don't send the normal one, then the Stop event
will be interpreted (by existing 4.0 slaves) as "the master stopped", which
is wrong. So for safety, given that we want minimum modification of 4.0, we
send the normal and fake Rotates.
*/
if (fake_rotate_event(net, packet, log_file_name, pos, &errmsg))
{
// tell the client log name with a fake rotate_event
if (fake_rotate_event(net, packet, log_file_name, &errmsg))
{
my_errno= ER_MASTER_FATAL_ERROR_READING_BINLOG;
goto err;
}
packet->set("\0", 1);
my_errno= ER_MASTER_FATAL_ERROR_READING_BINLOG;
goto err;
}
packet->set("\0", 1);
while (!net->error && net->vio != 0 && !thd->killed)
{
@ -585,10 +598,12 @@ Increase max_allowed_packet on master";
end_io_cache(&log);
(void) my_close(file, MYF(MY_WME));
// fake Rotate_log event just in case it did not make it to the log
// otherwise the slave make get confused about the offset
/*
Even if the previous log contained a Rotate_log_event, we still fake
one.
*/
if ((file=open_binlog(&log, log_file_name, &errmsg)) < 0 ||
fake_rotate_event(net, packet, log_file_name, &errmsg))
fake_rotate_event(net, packet, log_file_name, BIN_LOG_HEADER_SIZE, &errmsg))
{
my_errno= ER_MASTER_FATAL_ERROR_READING_BINLOG;
goto err;