1. A database system, comprising: a transaction aborter module to check whether or not a database transaction satisfies one or more invariants; a transaction manager module to obtain one or more locks for one or more resources required to perform the database transaction; a redo log manager module to append redo log records to a redo log stored on disk based on the database transaction; a memory; an in-core database module stored in the memory, the in-core database module storing structured data and references to unstructured data, wherein structured data required by the database transaction is sourced directly from the in-core database module without performing any disk accesses, and wherein each reference to unstructured data points to a location where the unstructured data is stored; a checkpointer module to update a database file stored on disk based on redo log records stored in the redo log, and to update, in the in-core database, a reference to unstructured data so that the reference points to the database file instead of the redo log; and a client response writer module to stream unstructured data from the redo log if the reference to the unstructured data stored in the in-core database module points to the redo log, or from the database file if the reference to the unstructured data stored in the in-core database module points to the database file.