Re: shared-memory based stats collector

On 2018-07-06 14:49:53 -0400, Robert Haas wrote:
> I think we also have to ask ourselves in general whether snapshots of
> this data are worth what they cost.  I don't think anyone would doubt
> that a consistent snapshot of the data is better than an inconsistent
> view of the data if the costs were equal.  However, if we can avoid a
> huge amount of memory usage and complexity on large systems with
> hundreds of backends by ditching the snapshot requirement, then we
> should ask ourselves how important we think the snapshot behavior
> really is.

Indeed. I don't think it's worthwhile major additional memory or code
complexity in this situation. The likelihood of benefitting from more /
better stats seems far higher than a more accurate view of the stats -
which aren't particularly accurate themselves. They don't even survive
crashes right now, so I don't think the current accuracy is very high.

Greetings,

Andres Freund