On Mon, Mar 22, 2021 at 07:38:41PM +0000, Werner Hunger wrote:
> Mio messages). The original code (in combination with our page
> templates) generates way too much database queries for one web request
> - MySQL is not able to handle this load with decent performance.
> Therefor we added support for bulk node prefetching with node id lists
> anticipated from preceeding query results, among other things.

There is a filter_iter instead of filter in back_anydbm (that also works
for mysql, at least it's tested :-)

For the typical loop

for id in db.someclass.filter(...):
    n = db.someclass.getnode(id)

This will not produce a database query for each getnode call when using
filter_iter instead of filter because filter_iter fetches the whole row
(not just the id) and pre-populates the cache in roundup. So the getnode
call already fetches from the cache.

This is not (yet?) used in the templates but it may speed up things for
some workloads.

> The reason i was looking into the current docs was to start estimating
> whether it would be feasible to migrate and merge our backend changes
> to Roundup 2.x - and thus gain Python 3 compatibility. If you'd like
> to, i can keep you posted once we decide to upgrade and the merge has
> been done.

Yes, I'd also like to know what you decide.

Ralf
-- 
Dr. Ralf Schlatterbeck                  Tel:   +43/2243/26465-16
Open Source Consulting                  www:   www.runtux.com
Reichergasse 131, A-3411 Weidling       email: office@runtux.com