Shared log-structured multi-version transactional datastore with metadata to enable melding trees

A concurrency control system, comprising:

• an ordered and shared log of indexed transaction records represented as multi-version data structures of nodes and node pointers, the log is a sole monolithic source of datastore state and is used for enforcing concurrency control;
• a transaction processing component that appends transaction records to the log from concurrent transactions executing on different multi-core processor cores, each node of a record is assigned a log address, a node dependency is stored in the log as a log address, and a node of the record is associated with versioned content identified in the log by a log address;
• and
• a microprocessor that executes computer-executable instructions in association with at least one of the log or the transaction processing component.

A concurrency control method performed by a computer system executing machine-readable instructions, the method comprising acts of:

• executing concurrent transactions on different cores of a multi-core processor;
• storing transaction records of the concurrent transactions as a monolithic index in an ordered and shared log;
• representing the records as data structures having nodes and node dependencies;
• tracking the nodes and node dependencies in the log using log addresses;
• and
• concurrently appending the records into the log at distinct log addresses.