PostgreSQL 9.5 Alpha 2 is out. We're still calling this one an Alpha instead of a Beta, because major replumbing is still underway. However, most of the issues reported with Alpha 1 have been fixed. A bunch of really useful bug reports came from regular users who tested out the alpha with their own workloads or tests, so please keep up the good work!
And, if you didn't test Alpha 1, well, we still need your help testing Alpha 2. Here's some ideas for what to test.
Again, to make testing easier for folks, I've created a docker image of Alpha 2. If you already run docker, simply run jberkus/postgres95-test and you can test our features without needing to worry about how to install Postgres. Specific notes on this test image are on the wiki.
As part of updating to alpha2, I managed to shrink the image by about 200MB by getting rid of a lot of build code. However, I did not remove 150MB of build and compile tools because I'm expecting testers to want to install additional extensions or tools in the image.