Re: pgsql: Add wait event for fsync of WAL segments

On 2018-Jul-03, Andres Freund wrote:

> On 2018-07-03 15:13:20 -0400, Alvaro Herrera wrote:
> > Are the numerical values actually exposed to the world? I thought the
> > only way to this info was through the system views, which surely expose
> > the names, not the numbers.
>
> There's at least some work at high frequency sampling of these, and I
> assume that's not going through SQL, but rather C functions.

You're right.

> > If reading wait events is actually possible, then it seems easy to
> > backpatch this in pg10 by putting the new value at the end of the
> > relevant enum, yeah.
>
> Honestly, I don't really see an argument for backpatching this. If
> people started measuring it might even invalidate their stats.

Hmm, if the stats are really invalidated by this change, then surely the
original numbers were incorrect anyway.

Anyway, it's not a huge deal to me. If Michael doesn't want to
backpatch it, it's his call, and I don't have the cycles to do it myself
right now either. If some other committer cares about it, well ...

--
Álvaro Herrera https://www.2ndQuadrant.com/
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