Re: implementing another hash join...

Martha Chronopoulou <mchron(at)aueb(dot)gr> writes:
> Im new to postgres and I'm about to implement the algorithm "double
> pipelined hash join". I've started using SPI functions but soon I
> realised that I 'm not at the right way (am I?).

Not even close. You need to be implementing new executor node types
(see backend/executor) and teaching the planner about the properties
of this join method. SPI is at a completely different level of
abstraction ...

> Is there a way that I'm not obliged to change code of the optimizer of
> postgres

Nope. The set of join types it knows about is pretty much hard-wired.

regards, tom lane