Re: de-dup process
- From: A Ebadi <ebadi01@xxxxxxxxx>
- To: Oracle-L@xxxxxxxxxxxxx, Tony van Lingen <tony.vanlingen@xxxxxxxxxxxxxx>
- Date: Mon, 22 Jan 2007 09:51:46 -0800 (PST)
Thanks to everyone's suggestions a few weeks ago regarding this de-dup issue.
I just wanted to let everyone know that the solution we decided on was to go
with hourly partitioning instead of daily which reduced our subset of data
which had to be de-duped by 24. The app had to be modified slightly to
accomplish this. Now, w are able delete out the dups (i.e. CTAS out the data
we are keeping). We are able to run many of these de-dups in parallel also.
Again, I understand this doesn't scale to infinity, but will get us by for
12-18 months based on the volume estimates.
Thanks,
Abdul
A Ebadi <ebadi01@xxxxxxxxx> wrote:
Putting a unique key constraint on it and loading it direct-path with dups
will insert the dups into the table and make the index unusable, so I don't
know how this could help us?
I don't want the dups inserted.
Thanks.
Tony van Lingen <tony.vanlingen@xxxxxxxxxxxxxx> wrote:
It may even be easier... You say "We are doing direct path load so no unique
key indexes can be put on the table to take care of the duplicates". The
utility guide (10gR2) however explicitly names unique constraints as a
constraint that can be enforced during direct path loads:
Integrity Constraints All integrity constraints are enforced during direct
path loads, although not necessarily at the same time. NOT NULL constraints are
enforced during the load. Records that fail these constraints are rejected.
UNIQUE constraints are enforced both during and after the load. A record that
violates a UNIQUE constraint is not rejected (the record is not available in
memory when the constraint violation is detected).
(Utilities, B14215-01 chapter 11).
Did you actually try this?
Cheers,
Tony
A Ebadi wrote: We have a huge table (> 160 million rows) which has about 20
million duplicate rows that we need to delete. What is the most efficient way
to do this as we will need to do this daily?
A single varchar2(30) column is used to identified duplicates. We could
possibly have > 2 rows of duplicates.
We are doing direct path load so no unique key indexes can be put on the
table to take care of the duplicates.
Platform: Oracle 10G RAC (2 node) on Solaris 10.
Thanks!
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