Re: How to do faster updates

From: Jeff Landers <jlanders_at_convergys.com>
Date: Fri, 13 Sep 2002 10:58:22 -0800
Message-ID: <F001.004CFC0D.20020913105822@fatcity.com>

Pillai, Rajesh wrote:

> Hi All,
> I've a table of 10 M records and I want to update some thousand records based on a column which is not a part of any index. Please suggest the quickest way to do this.
>
> Thanks,
> Rajesh
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Pillai, Rajesh
> INET: Rajesh.Pillai_at_nordstrom.com
>
> Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
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  Bulk collect the rowid's of the rows you want to update. Then use the forall statement to bulk update the rows. Very, very fast.

Here is an example:

set serveroutput on size 1000000
declare

        type my_array_type is table of rowid
                index by binary_integer;

        my_array        my_array_type;
        rows            natural := 15000;
        loop_count      pls_integer := 0;


        --
        --
        cursor bill_cur is
                select b.rowid from bill b where b.person_id = 'xyz';

        begin


        open bill_cur;
        loop
                fetch bill_cur bulk collect into my_array limit rows;
                exit when bill_cur%NOTFOUND;

                loop_count := loop_count + 1;
                forall indx in my_array.first..my_array.last
                        update bill set person_id = 'abc'
                                where ROWID = my_array(indx);
                commit;
                my_array.DELETE;
         end loop;

        ---

        if my_array.COUNT > 0 then
                forall indx in my_array.first..my_array.last
                update bill set person_id = 'abc'
                        where ROWID = my_array(indx);
                commit;
        end if;

        close bill_cur;
        dbms_application_info.set_client_info( Total Loops: '|| loop_count );


        exception
                when others then
                commit;

end;
/

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Jeff Landers
  INET: jlanders_at_convergys.com

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists
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also send the HELP command for other information (like subscribing).

Received on Fri Sep 13 2002 - 13:58:22 CDT