Hi Frédéric,
Thanks a lot for trying out my (first) patch! Much appreciated.
On 20/07/2025 21:54, Frédéric Yhuel wrote:
> Your patch applies cleanly and seems to work well.
Cool!
> because most of the index non-leaf pages should be in the cache. Right?
Yes indeed, it's an assumption in the implementation, that the non-leaf
pages will roughly always be in the cache.
> This should probably be documented somewhere?
I'm still familiarising myself about what to document where, whether
things should be in the official docs or separate blog posts. In the
patch I only documented the new column next to the existing ones for now.
> --> 3 pages: the root of the tree, one internal page and one leaf
Yes, this is correct.
> primary sleaf bench [42323] # select idx_blks_read, idx_blks_hit,
> idx_metadata_blks from pg_statio_all_indexes where indexrelname =
> 'pgbench_accounts_pkey';
> idx_blks_read | idx_blks_hit | idx_metadata_blks
> ---------------+--------------+-------------------
> 4 | 3 | 5
>
> --> 4 more pages: same as before, already in cache, plus the index
> meta page, read outside shared buffers because we started a new session?
Yes, that's my understanding too.
Thanks!
Kind regards,
Mircea Cadariu
