RE: "DB Link are Inherently Slow" -- True or False?

  • From: "Powell, Mark D" <mark.powell@xxxxxxx>
  • To: "Oracle List" <oracle-l@xxxxxxxxxxxxx>
  • Date: Tue, 15 Jul 2008 12:51:24 -0400

Slow is a relative term.  If the alternate transfer method is an export,
FTP, and import then even if the insert select across the link was
slower than the import step it is likely to be faster than the combined
exp/imp or exp/FTP/imp process.
The real question is how important is the transfer speed?  How often
will the transfer need to be performed?  Will the receiving object need
to be re-created, cleared out prior to the task or will the data need to
be merged?  If the data is merged what are the chances of getting an
The answers to these questions should allow you to choose the best
solution for your needs.
-- Mark D Powell -- 
Phone (313) 592-5148 


        From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Howard Latham
        Sent: Tuesday, July 15, 2008 10:43 AM
        To: david@xxxxxxxxxxxxxxxxxx
        Cc: Oracle List
        Subject: Re: "DB Link are Inherently Slow" -- True or False?
        DB Links can be slow -or slow down processing - and for two
reasons -
        1. Network is Slow
        2. Code
        Some code is slowed down badly by using a DB Link. I'm not sure
why by some apps really suffer 
        while others don't I think it's to with what is is happening in
which database.
        On the OTHER HAND COPY over a DBLINK can be VERY VERY FAST! and
therefore one of the best ways for bulk transfer of data.
        2008/7/15 David Aldridge <david@xxxxxxxxxxxxxxxxxx>:

I am being persistently told by a DBA that DB links are inherently slow
and not suited to bulk transfer of data.
Does anyone have any experiences to share on the sort of practical
MBytes/sec throughput we ought to be getting on a 10GBit network between
two databases having no intervening firewalls, routers, or other
potentially performance limiting network components? We're seeing
2MBytes/sec using data pump import in network mode with parallelsim of
10 (ie. sourcing data through a db link from another db on a different
host) :(

        Howard A. Latham

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