Re: [HACKERS] Re: pgsql: Avoid extra locks in GetSnapshotData if old_snapshot_threshold < - Mailing list pgsql-committers

From Andres Freund
Subject Re: [HACKERS] Re: pgsql: Avoid extra locks in GetSnapshotData if old_snapshot_threshold <
Date
Msg-id 20160416205630.puxsglckxi3sn5ec@alap3.anarazel.de
Whole thread Raw
In response to Re: pgsql: Avoid extra locks in GetSnapshotData if old_snapshot_threshold <  (Noah Misch <noah@leadboat.com>)
Responses Re: [HACKERS] Re: pgsql: Avoid extra locks in GetSnapshotData if old_snapshot_threshold <  (Amit Kapila <amit.kapila16@gmail.com>)
List pgsql-committers
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


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