Re: stats test intermittent failure

Hi,

On 2023-07-31 21:03:07 +0900, Masahiko Sawada wrote:
> Regarding the patch, I have a comment:
>
> -- Test that reuse of strategy buffers and reads of blocks into these reused
> --- buffers while VACUUMing are tracked in pg_stat_io.
> +-- buffers while VACUUMing are tracked in pg_stat_io. If there is sufficient
> +-- demand for shared buffers from concurrent queries, some blocks may be
> +-- evicted from the strategy ring before they can be reused. In such cases
> +-- this, the backend will evict a block from a shared buffer outside of the
> +-- ring and add it to the ring. This is considered an eviction and not a reuse.
>
> The new comment seems not to be accurate if my understanding is correct. How
> about the following?
>
> Test that reuse of strategy buffers and reads of blocks into these
> reused buffers while VACUUMing are tracked in pg_stat_io. If there is
> sufficient demand for shared buffers from concurrent queries, some
> buffers may be pinned by other backends before they can be reused. In
> such cases, the backend will evict a buffer from a shared buffer
> outside of the ring and add it to the ring. This is considered an
> eviction and not a reuse.

I integrated the suggested change of the comment and tweaked it a bit
more. And finally pushed the fix.

Sorry that it took so long.

Greetings,

Andres Freund