Re: [HACKERS] Re: pgsql: Avoid extra locks in GetSnapshotData if old_snapshot_threshold <

On 2016-04-16 16:44:52 -0400, Noah Misch wrote:
> That is more controversial than the potential ~2% regression for
> old_snapshot_threshold=-1.  Alvaro[2] and Robert[3] are okay releasing
> that way, and Andres[4] is not.

FWIW, I could be kinda convinced that it's temporarily ok, if there'd be
a clear proposal on the table how to solve the scalability issue around
MaintainOldSnapshotTimeMapping(). Postponing the optimization around
something as trivial as a spinlock around reading an LSN is one thing,
postponing something we don't know the solution to is anohter.

Andres