Log-based concurrency control using signatures

摘要

A transaction request is received at a log-based transaction manager, indicating a conflict check delimiter and a read set descriptor indicative of one or more locations from which data is read during the requested transaction. Using the conflict check delimiter, a subset of transaction records stored in a particular persistent log to be examined for conflicts prior to committing the requested transaction is identified. In response to determining that none of the read locations of the requested transaction correspond to a write location indicated in the subset of transaction records, a new transaction record is stored in the particular persistent log indicating that the requested transaction has been committed.

主权项

1. A non-transitory computer-accessible storage medium storing program instructions that when executed on one or more processors:
receive, at a log-based transaction manager, a transaction descriptor of a requested transaction from a client, wherein the transaction descriptor comprises at least (a) respective read signatures indicative of one or more objects from which data is read during the requested transaction, including a first object at a first data store and a second object at a second data store, (b) a first committed state identifier (CSI) determined based at least in part on a first logical timestamp corresponding to a first previously-committed transaction at the first data store and a second logical timestamp corresponding to a second previously-committed transaction at the second data store, and (c) respective write signatures indicative of one or more objects to which data is to be written in response to a commit of the requested transaction; identify, by the log-based transaction manager using the first CSI, a subset of transaction records stored in a particular persistent log to be examined for conflicts prior to committing the requested transaction, wherein the particular persistent log comprises transaction records corresponding to previously-committed transactions associated with one or more data stores including the first and second source data stores, in response to a determination, by the log-based transaction manager, that none of the objects indicated by the read signatures of the requested transaction have been modified by a write operation indicated in the subset of transaction records, accept the requested transaction for commit.