While having parallelism is awesome, it's only going to affect a (arguably small or big depending on your viewpoint) subset of users. It's going to be massive for those users, but it's not going to be useful for anywhere near as many users as streaming replication+hot standby+pg_upgrade in 9.0, or pitr+windows in 8.0. And yes, the vacuum freeze thing is also going to be great - for a small subset of users (yes, those users are in a lot of pain now).
We don't yet have full parallel query, we only have parallel scan and parallel aggregation.
My comment here missed the point that parallel hash join is also now possible for small hash tables, so we at least have a useful subset of functionality across parallel scan/join/agg.
I'm still in favour of a compatibility break, planned in advance and it makes most sense to call that 10.0, but if we are never going to do that, then we can call this release anything we like. I'd guess the Dev meeting in Ottawa would decide that.
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Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services