Elastic Transactions are a complementary alternative to traditional transactions, particularly appealing when implementing search structures. Both forms of transactions can safely be combined within the same application. Elastic transactions are a variant of the transactional model. Upon conflict detection, an elastic transaction might drop what it did so far within a separate transaction that immediately commits, and initiate a new transaction which might itself be elastic.

ε-STM is the first software transactional memory supporting elastic transactions. ε-STM implementation is faster than a state-of-the-art software transactional memory in various workloads and with a speedup of 36% on average. Here is the simple API, ε-STM provides to the user:

• BEGIN(elastic);
• BEGIN(normal);
• END;
• READ(x);
• WRITE(x,v).

The simplicity of using ε-STM comes from the very few information the programmer has to provide. The programmer has to indicate whether his(her) transaction is normal or elastic and no extra-information (i.e., release action, or on-abort-action) is necessary.

ε-STM is created/maintained by Vincent Gramoli.

Here is our word-based version of ε-STM, implemented in C.

• estm-0.2.7.

Here is our field-based version of ε-STM, implemented in Java. It requires the Deuce instrumentation framework.

• estm-java-0.2.

Felber, P., Gramoli, V., Guerraoui, R. (2009) Elastic Transactions. Proceedings of the 23rd International Symposum on Distributed Computing (DISC).