MySQL 8.0 C API Developer Guide  /  C API Binary Log Function Descriptions

Chapter 21 C API Binary Log Function Descriptions

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 @source_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 @source_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 the client directory

  • mysql_client_test.c in the testclients directory