hi, all

I'm handling something about sharding (or partition) recently. What I
want to do is to add more machines or nodes to my system so that
storing more data is possibale (maybe scale-out?).

I found many people add a middle layer between their applications and
databases, mysql for example. That seems to be perfect for me at first
glance. But then I'm puzzled about the query and join operation.

Q1:
How to handle queries with offset and limit like:

'select * from xxxx where yyyy order by col_a asc limit num_b, num_c'

Just perform the query 'select * from xxxx where yyyy order by col_a
asc limit 0, num_b + num_c' on each machine, merge the results and
return [num_b, num_b + num_c)?

Q2:
How to handle the join operations within different databases?

Sorry for my poor English expression, and I'll be very appreciative if
you can give me a hand, thx!



Abioy