1. In a unified table architecture of an in-memory computing system having a multi-level storage architecture, the storage architecture having a first level storage structure to store incoming data requests in a logical row format as data records, a second level storage structure to encode and store the data records in a logical column format, and a main store to compress and store the encoded data records for long-term storage, a method of log-less atomic data movement, the method comprising: starting an internal transaction within the multi-level storage architecture, the internal transaction to merge data from the first level storage structure to the second level storage structure; reading committed data from the first level storage structure as specified by the internal transaction; inserting the committed data from the first level storage structure into the second level storage structure in a bulk insertion process; marking the committed data as being deleted from the first level storage; and committing the internal transaction to the multi-level storage when the committed data has been inserted into the second level storage structure.