Scm-conscious transactional key-value store

Abstract

Embodiments of a method are described. In one embodiment, the method is a method for executing and supporting transactions. The method includes receiving a transaction comprising a command and data. The method includes writing the data to a transaction manager on a persistent memory device. The transaction manager also maintains a status of the transaction and reference to entries within memory that are manipulated by the transaction. The method also includes creating an in-memory log of the transaction in a first hash directory. The method includes committing a copy of the first hash directory to a second hash directory maintained on a persistent memory device.

What is claimed is: 
     
         1 . A method for executing and supporting transactions, the method comprising:
 receiving a transaction comprising a command and data;   writing the data to a transaction manager on a persistent memory device, wherein the transaction manager maintains a status of the transaction and reference to entries within the memory that are manipulated by the transaction;   creating a log of the transaction on a first hash directory; and   committing a copy of the first hash directory to a second hash directory, wherein the second hash directory is on the persistent memory device.   
     
     
         2 . The method of  claim 1 , wherein the persistent memory device is a storage class memory device comprising phase change memory. 
     
     
         3 . The method of  claim 1 , further comprising maintaining a record of indexing information on transaction manager, wherein the record of indexing information comprises data related to at least one hash entry within the first and second hash directories affected by the transaction. 
     
     
         4 . The method of  claim 1 , further comprising maintaining a status of each hash entry in a corresponding flag field, wherein each flag field comprises data indicating an in-use, deleted, and ever-deleted status of the corresponding hash entry. 
     
     
         5 . The method of  claim 1 , further comprising creating at least one save point in the transaction manager, wherein the save point corresponds to a hash entry on the first or second hash directory where each of the hash entries in use by the transaction prior to the save point have been committed to the second hash directory. 
     
     
         6 . The method of  claim 1 , further comprising:
 rolling back a transaction on the first and second hash directories, wherein rolling back a transaction comprises:
 determining whether entries of the first and second hash directory have been committed to the second hash directory; and 
 returning the first and second hash directories to a state prior to the start of the transaction.