Re: WIP: WAL prefetch (another approach)

Hi,

On 2020-12-04 13:27:38 -0500, Stephen Frost wrote:
> If I follow correctly, this patch will scan ahead in the WAL and let
> the kernel know that certain blocks will be needed soon.  Ideally,
> though I don't think it does yet, we'd only do that for blocks that
> aren't already in shared buffers, and only for non-FPIs (even better if
> we can skip past pages for which we already, recently, passed an FPI).

The patch uses PrefetchSharedBuffer(), which only initiates a prefetch
if the page isn't already in s_b.

And once we have AIO, it can actually initiate IO into s_b at that
point, rather than fetching it just into the kernel page cache.

Greetings,

Andres Freund