distributed pushed-down join - part II

now also support table/index scan as root node, i.e tree = [ scan ] ? [ lookup ] *
still with the limitations:
- a child may only be dependent on immediate parent
- still only left outer join.

i also completed the parameterized scan-filter inside tup but does not yet support this in spj or ndbapi.

currently working on
- the parameterized scan-filer in spj (and a tiny bit in the ndbapi).
- result set correlation

currently thinking on
- arena based allocator for spj-requests, (compare mysqld mem-root concept)

discussed with frazer what spj "really is", concluded that it probably is some kind of "data-flow-engine"...should probably find some hip acronym/term for it...

note:
current mental capacity is limiting spj to only one scan in a tree.
this limitation can of course be lifted...but not now, or my brain will fry.

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wonder how i should make people giving me votes on planetmysql??