Transactional key-value store

Example implementations disclosed herein can be used to build, maintain, and access databases built database in multi-core computing systems with large VRAM and huge NVRAM. The database with optimistic concurrency control can be built on a transactional key-value data store that includes logically equivalent data pages stored in both VRAM and VRAM. Data records in volatile data pages in the VRAM represent the most recent version of the data. Data records in the NVRAM immutable and are organized in a stratified composite snapshot. A distributed log gleaner process is used to process log entries corresponding to transactions on the volatile data pages and construct the snapshot. The log gleaner sorts the log entries by epoch, key range, and most recent use to partition the snapshot across multiple nodes.