Re: What is the fastest way to dump oracle data into a human

Options #1 (Perl) and #2 (PRO*C) would be fastest and easiest. The PRO*C demo programs provide a decent start, for option #2. Option #3 (OCI) would be not faster than PRO*C and, due to the increased complexity of OCI, a more problematic approach.

SQL*Plus is the easiest method to implement by far, but the SQL*Plus program introduces a surprising amount of "overhead" processing, making it much slower than Perl or PRO*C, but much faster than UTL_FILE. If you are not in a big time crunch but want decent performance, use SQL*Plus. If you are in a time crunch and need the best performance, use Perl or PRO*C.

on 1/10/04 6:09 PM, Guang Mei at gmei_at_incyte.com wrote:

> Hi:
>
> I have a program (running on oracle 8173 server) that writes 48 Millions
> lines of data into various text files . The selected data is from various
> tables and I have the query pretty much optimized. Now I am trying to find
> the fastest way to dump the selected data into a text file on the same
> oracle server. The program (written as a pl/sql package) now works
> something like this:
>
> str varchar2(32767) := '';
> NL char(1) := chr(10); -- new line character
> begin
> fpn := utl_file.fopen(directory, filename, 'w', 32767);
> for x in cur1 loop
> str := str || x.str || NL; -- keep building the str
> if (length (str) > 31000 ) then
> str := substr (str,1, length(str) -1 );
> utl_file.put_line(fpn, str);
> str := '';
> end if;
> end loop;
>
> -- dump the last part:
> str := substr (str,1, length(str) -1 );
> utl_file.put_line(fpn, str);
> utl_file.fflush(fpn);
> utl_file.fclose(fpn);
> end ;
>
>
> The above code works perfect fine now. But I am wondering if there is
> another way that could increase the writing siginificantly faster. This
> porgram does not have to be in pl/sql. I can think of a couple of
> potential approaches:
>
> 1. Write a perl program, basically using perl's DBI/DBD to select the data
> from the database, then calling perl's "print" to write data into a file.
> I have not tested this and don't know if it is faster that
> utl_file.put_line.
>
> 2. Write a C program, using ProC to talk to DB, then use C's fopen and
> fwrite(?) to dump data into text file.
>
> 3. Write a C program,using OCI to talk to DB, then use C's fopen and
> fwrite(?) to dump data into text file.
>
> I don't have direct experience with ProC and OCI, so I don't know how
> faster (or any) it would be by doing Option 2 or 3 above. Does anyone
> know if I would see siginificant performance boost by using C? Any other
> suggestions?
>
> TIA.
>
> Guang
>
>

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Tim Gorman
  INET: tim_at_sagelogix.com

Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
San Diego, California        -- Mailing list and web hosting services
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).