A system includes writing of log data in chunks over a first range of heap log sequence positions of a heap log stored in the non-volatile memory system, and writing of a heap anchor marker in a first anchor stream of a transaction log stored in the non-volatile memory system, at a first transaction log sequence position of the transaction log, wherein the first anchor stream is associated with a first stream of the transaction log, and the heap anchor marker identifies the first range of heap log sequence positions of the heap log.