[wolle]

Depending on your requirements, a single-node solution like PipelineDB may suffice; it's a PostgreSQL extension that lets you write streaming SQL queries.

[Fergi]

Jeff from PipelineDB here. We are also rolling out a SaaS product based on PipelineDB called Stride (stride.io) that enables this type of computation via an API with little to no overhead.

[justinsaccount]

That is definitely along the lines of what I'm looking for..

the esper stuff was on my radar, but something that works with existing postgresql tools is a huge plus.

[avifreedman]

PipelineDB can scale out to multiple nodes (for $).

[wolle]

Is there a reference regarding the number of nodes that can be deployed in the cluster, and are feasible to maintain? From the docs, I gather that "[a]ll DDL/non-stream DML statements are executed in a distributed transaction on all nodes in the cluster and committed via two-phase commit." [1]

Doesn't that get in the way of low latency and availability?

[1] http://enterprise.pipelinedb.com/docs/two-phase.html#two-pha...