Stateless datastore-independent transactions

A method, comprising:

• performing, by one or more computing devices:
• receiving, at a client-side component of a storage group comprising one or more data stores including a first data store, respective read descriptors corresponding to one or more reads, including a first read descriptor corresponding to a first read directed to the first data store, wherein the first read descriptor comprises an indication of a state transition that has been applied at the first data store;
• generating, at the client-side component, respective write descriptors of one or more writes, including a first write descriptor of a first write directed to a particular data store of the one or more data stores, wherein a payload of the first write is based at least in part on a result of the first read, and wherein the first write descriptor indicates an object to be modified at the particular data store;
• transmitting, from the client-side component to a transaction manager, a commit request for a candidate transaction comprising one or more writes including the first write, wherein the commit request comprises at least the first read descriptor and the first write descriptor;
• determining, at the transaction manager, that the candidate transaction is to be accepted for commit based at least in part on an analysis of the first read descriptor.

A non-transitory computer-accessible storage medium storing program instructions that when executed on one or more processors:

• receive, at a client-side component of a storage group comprising one or more data stores including a first data store, respective read descriptors corresponding to one or more reads, including a first read descriptor corresponding to a first read directed to the first data store, wherein the first read descriptor comprises an indication of a state transition that has been applied at the first data store;
• generate, at the client-side component, respective write descriptors of one or more writes, including a first write descriptor of a first write directed to a particular data store of the one or more data stores, wherein a payload of the first write is based at least in part on a result of the first read, and wherein the first write descriptor indicates an object to be modified at the particular data store;
• and
• transmit, from the client-side component to a transaction manager, a commit request for a candidate transaction comprising one or more writes including the first write, wherein the commit request comprises at least the first read descriptor and the first write descriptor.