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• Optimizes local processing
time & communication time.
time • Optimizer, based on
stats of DB and size of
iterm results, decides
–Join Algo (nested/mergeJoin)
–Access path (indexed/seq.). • Inter-site transfers
• Entire relation transferred
• Stored in a temp relation
• In case of merge-join approach, tuples can
be processed as they arrive – Fetch-as-needed
• nExternal relation is sequentially scanned
• Join attribute value is sent to other relation
• Relevant tuples scanned at other site and
sent to first site. • Inter-site tran...
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- Fall '09