The following sections provide detailed descriptions of the functions that enable reading the stream of replication events from a MySQL server binary log.
The following simple example program demonstrates the binary log C API functions. Program notes:
mysql
is assumed to be a valid connection handler.The initial
SET
statement sets the@master_binlog_checksum
user-defined variable that the server takes as an indication that the client is checksum-aware. This client does nothing with checksums, but without this statement, a server that includes checksums in binary log events will return an error for the first attempt to read an event containing a checksum. The value assigned to the variable is immaterial; what matters is that the variable exist. existence.
if (mysql_query(mysql, "SET @master_binlog_checksum='ALL'"))
{
fprintf(stderr, "mysql_query() failed\n");
fprintf(stderr, "Error %u: %s\n",
mysql_errno(mysql), mysql_error(mysql));
exit(1);
}
MYSQL_RPL rpl;
rpl.file_name_length = 0;
rpl.file_name = NULL;
rpl.start_position = 4;
rpl.server_id = 0;
rpl.flags = 0;
if (mysql_binlog_open(mysql, &rpl))
{
fprintf(stderr, "mysql_binlog_open() failed\n");
fprintf(stderr, "Error %u: %s\n",
mysql_errno(mysql), mysql_error(mysql));
exit(1);
}
for (;;) /* read events until error or EOF */
{
if (mysql_binlog_fetch(mysql, &rpl))
{
fprintf(stderr, "mysql_binlog_fetch() failed\n");
fprintf(stderr, "Error %u: %s\n",
mysql_errno(mysql), mysql_error(mysql));
break;
}
if (rpl.size == 0) /* EOF */
{
fprintf(stderr, "EOF event received\n");
break;
}
fprintf(stderr, "Event received of size %lu.\n", rpl.size);
}
mysql_binlog_close(mysql, &rpl);
For additional examples that show how to use these functions, look in a MySQL source distribution for these source files:
mysqlbinlog.cc
in theclient
directorymysql_client_test.c
in thetestclients
directory