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MXS-2785: Prevent broken replication setups

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When rewrite_src and rewrite_dest have different lengths, the slave must
use GTID based replication. This removes the need for one-to-one matching
between the slave's relay log and the master's binlog which gets broken
when event lengths are modified due to event rewriting.
This commit is contained in:
Markus Mäkelä
2019-12-05 11:45:04 +02:00
parent 3de5e4edcd
commit d23f0366a8
2 changed files with 30 additions and 3 deletions
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32
server/modules/filter/binlogfilter/binlogfiltersession.cc
View File

@ -90,16 +90,24 @@ BinlogFilterSession* BinlogFilterSession::create(MXS_SESSION* pSession,
return new BinlogFilterSession(pSession, pFilter);
}
static bool is_master_binlog_checksum(GWBUF* buffer)
static bool is_matching_query(GWBUF* buffer, const char* target)
{
const char target[] = "SELECT @master_binlog_checksum";
char query[1024]; // Large enough for most practical cases
size_t bytes = gwbuf_copy_data(buffer, MYSQL_HEADER_LEN + 1, sizeof(query) - 1, (uint8_t*)query);
query[bytes] = '\0';
return strcasestr(query, target);
}
static bool is_master_binlog_checksum(GWBUF* buffer)
{
return is_matching_query(buffer, "SELECT @master_binlog_checksum");
}
static bool is_using_gtid(GWBUF* buffer)
{
return is_matching_query(buffer, "SET @slave_connect_state=");
}
/**
* Route input data from client.
*
@ -129,6 +137,19 @@ int BinlogFilterSession::routeQuery(GWBUF* pPacket)
// Connected Slave server is waiting for binlog events
m_state = BINLOG_MODE;
MXS_INFO("Slave server %u is waiting for binlog events.", m_serverid);
if (!m_is_gtid
&& m_filter.getConfig().rewrite_src.length() != m_filter.getConfig().rewrite_dest.length())
{
gwbuf_free(pPacket);
std::ostringstream ss;
ss << "GTID replication is required when '"
<< REWRITE_SRC << "' and '" << REWRITE_DEST << "' are of different length";
mxs::FilterSession::clientReply(
modutil_create_mysql_err_msg(1, 0, ER_MASTER_FATAL_ERROR_READING_BINLOG, "HY000",
ss.str().c_str()));
return 0;
}
break;
case MXS_COM_QUERY:
@ -136,6 +157,11 @@ int BinlogFilterSession::routeQuery(GWBUF* pPacket)
m_state = COMMAND_MODE;
m_reading_checksum = is_master_binlog_checksum(pPacket);
gwbuf_set_type(pPacket, GWBUF_TYPE_COLLECT_RESULT);
if (is_using_gtid(pPacket))
{
m_is_gtid = true;
}
break;
default:

1
server/modules/filter/binlogfilter/binlogfiltersession.hh
View File

@ -124,4 +124,5 @@ private:
uint32_t m_large_left = 0; // Remaining bytes of a large event
bool m_is_large = false; // Large Event indicator
bool m_reading_checksum = false;// Whether we are waiting for the binlog checksum response
bool m_is_gtid = false;
};