Fencing mechanism of statements for distributed multi-version concurrency control

A method comprising:

• determining that a request to commit a transaction has been received;
• prior to committing the transaction and after receiving the request to commit the transaction, performing a write operation to store a metadata version of a table associated with the transaction in a metastore;
• performing as part of performing the request to commit the transaction, by a compute service manager, a register operation to register a background worker, the background worker being initiated by a fencing manager provided by the compute service manager, the fencing manager being a different component from a transaction manager provided by the compute service manager;
• performing, by the background worker, a trigger operation to perform an execution node job on an execution node;
• retrieving, by the execution node job, a set of identifiers of active transactions;
• performing, by the execution node job, a metadata version validation process comprising:
• retrieving a first metadata version, stored in a table persistence object, of the table in the metastore;
• retrieving a second metadata version of the table from a datastore;
• comparing the first metadata version with the second metadata version;
• determining whether the metadata version validation process fails when the first metadata version is less than the second metadata version, and a read timestamp associated with the transaction is not earlier than a write timestamp associated with the second metadata version;
• and
• determining that the metadata version validation process is successful when determining that the metadata version validation process does not fail;
• performing, by the execution node job, a write operation to store the metadata version of the table and the set of identifiers in a datastore;
• receiving, by the background worker, an indication that the execution node job has successfully completed;
• and
• performing, by the background worker, an unlock operation to unlock the table.

A non-transitory computer-storage medium comprising instructions that, when executed by one or more processors of a machine, configure the machine to perform operations comprising:

• determining that a request to commit a transaction has been received;
• prior to committing the transaction and after receiving the request to commit the transaction, performing a write operation to store a metadata version of a table associated with the transaction in a metastore;
• performing as part of performing the request to commit the transaction, by a compute service manager, a register operation to register a background worker, the background worker being initiated by a fencing manager provided by the compute service manager, the fencing manager being a different component from a transaction manager provided by the compute service manager;
• performing, by the background worker, a trigger operation to perform an execution node job on an execution node;
• retrieving, by the execution node job, a set of identifiers of active transactions;
• performing, by the execution node job, a metadata version validation process comprising:
• retrieving a first metadata version, stored in a table persistence object, of the table in the metastore;
• and
• retrieving a second metadata version of the table from a datastore;
• comparing the first metadata version with the second metadata version;
• determining whether the metadata version validation process fails when the first metadata version is less than the second metadata version, and a read timestamp associated with the transaction is not earlier than a write timestamp associated with the second metadata version;
• and
• determining that the metadata version validation process is successful when determining that the metadata version validation process does not fail;
• performing, by the execution node job, a write operation to store the metadata version of the table and the set of identifiers in a datastore;
• receiving, by the background worker, an indication that the execution node job has successfully completed;
• and
• performing, by the background worker, an unlock operation to unlock the table.