sparql engine execution hints

hi,

has this already been discussed (is it a good idea?)
to include hints for the sparql engine what to execute first?

i know that every engine has optimizer that do their best, but sometimes
i just do know better :-)

in such cases i wouldn't actually want to change my triple store to find
the one that executes the query the way i like it.

one such use case would be from the realm of federated queries where i can
move local stuff in the query to the same level of the service keyword by
using
a subquery (according to spec). but what would be executed first subquery
or service?

any pointer to previous discussions and/or comments highly welcome.

wkr jürgen

| Jürgen Jakobitsch,
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