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emsgal2017 avatar image
emsgal2017 asked

Linked Tables inefficient?

I have a project that I am converting from MS Access to MS SQL 2008. I have a need to link and join query from foreign Oracle tables to my local tables. I am being told by my SQL DBA that Linked tables, OpenQuery or OpenRowset are all inefficient because what happens in the background is that every row from the foreign table is read into the SQL db each time the query is run to be able to do the join with local tables. This doesnt sound right to me, is this true?
openqueryopenrowsetlinked
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DenisT answered
You could read this blog -- http://thomaslarock.com/2013/05/top-3-performance-killers-for-linked-server-queries/ -- plus def. advise you to watch Connor's video from SQLBits -- http://sqlbits.com/Sessions/Event10/Distributed_Query_Deep_Dive -- nobody can explain this concept better than him!
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