A first log reader publishes first messages to a plurality of queues. The first messages comprise changes for transactions extracted from a log by the first log reader. In response to one of the queues becoming unavailable, launching a second log reader to read and extract from the log, and to publish second messages comprising changes for transactions extracted from the log by the second log reader to the unavailable queue as a catch-up queue. In response to the catch-up queue becoming available and the second log reader reaches the end of the log, the publishing of the second messages for the catch-up queue is transferred from the second log reader to the first log reader.