Re: faster way to create XML export
Date: Tue, 2 Aug 2011 18:34:24 -0500
Message-ID: <CA+fnDAa3tXvOrEGWgrXr6FfXwtL36NXxftdhvBZuA-G3_ajCWA_at_mail.gmail.com>
Oh yeah, we also tested with the DBMS_XMLQuery package - it seemed to take about as long as the Oracle Serializer java code.
On Tue, Aug 2, 2011 at 6:19 PM, Jeremy Schneider < jeremy.schneider_at_ardentperf.com> wrote:
> Well we're not making any 1GB files yet, but I can't really imagine what
> anyone does with a 400MB file either. Anyway - we were doing some testing
> with a much smaller "test" dataset (8MB file), and we tried Marco's idea.
> Here are the results:
>
> Original Code: 96 sec
> Oracle Serializer: 40 sec
> Marco's Code: 3 sec
>
> :)
>
> Sweet! However, it seems that there's an implicit conversion from XMLType
> to CLOB and it's not immediately obvious how to control the XML that's
> generated. I guess it's time for me to learn some more about XMLDB. :-/
> Here's what we're trying to figure out how to do with XMLType:
>
> - xmlQuery.keepCursorState(true);
> - xmlQuery.setMaxRows(pRowLimit_variable); // Note: we continue with
> cursor and split output to multiple files
> - xmlQuery.setRowTag(pRowHeader_variable);
> - xmlQuery.setRowsetTag(pRowHeader_variable+"_MYSUFFIX");
> - xmlQuery.setDateFormat("yyyy-MM-dd'T'HH:mm:ss");
> - xmlQuery.setStylesheetHeader(pXSLtURI_variable);
>
> Any tips would be appreciated...
>
> -J
>
>
> PS - this blog post by Marco is excellent:
> http://www.liberidu.com/blog/?p=369
>
>
> On Tue, Aug 2, 2011 at 4:41 PM, Marco Gralike <Marco.Gralike_at_amis.nl>wrote:
>
>> ONE 1++GB in XML document, are you serious.
>> Wouldn't be surprised though. I see it more and more often. ;-)
>>
>> No the stuff showed below is in C and/or even part of the C kernel. It is
>> possible to do in SQL and yes due to the fact that it is 1 XML document you
>> will get in trouble regarding those mentioned sizes per XML document. I am
>> guessing, although never really checked that if you switched it again for a
>> C based SAV serializer it would be even faster or does it reside in the JVM
>> database kernel?
>>
>> I wonder which part picks up those big XML documents and tries to do
>> something useful with it. Work to be done with those documents afterwards
>> most be very resource intensive ;-)
>>
>
-- http://www.ardentperf.com +1 312-725-9249 Jeremy Schneider Chicago -- http://www.freelists.org/webpage/oracle-lReceived on Tue Aug 02 2011 - 18:34:24 CDT