Re: Custom explain options

On 10/21/23 14:16, Konstantin Knizhnik wrote:
> Hi hackers,
>
> EXPLAIN statement has a list of options (i.e. ANALYZE, BUFFERS,
> COST,...) which help to provide useful details of query execution.
> In Neon we have added PREFETCH option which shows information about page
> prefetching during query execution (prefetching is more critical for Neon
> architecture because of separation of compute and storage, so it is
> implemented not only for bitmap heap scan as in Vanilla Postgres, but
> also for seqscan, indexscan and indexonly scan). Another possible
> candidate  for explain options is local file cache (extra caching layer
> above shared buffers which is used to somehow replace file system cache
> in standalone Postgres).

Not quite related to this patch about EXPLAIN options, but can you share
some details how you implemented prefetching for the other nodes?

I'm asking because I've been working on prefetching for index scans, so
I'm wondering if there's a better way to do this, or how to do it in a
way that would allow neon to maybe leverage that too.

regards

--
Tomas Vondra
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company