XML Tag breaking in the middle when Chunking XMLTYPE to CLOB - sql

Question

We have a procedure that writes a XML File using SQL and we're asked to improve it's performance. Currently, it prints the XML line-by-line like the code below:
begin
dbms_output.put_line('<tns:jpk>');
-- header section
for i in (select xmlelement("tns:header", header_num)
,xmlelement("tns:customer", customer_name)
,xmlelement("tns:po_number", po_number) li_xml
from header_tbl) loop
dbms_output.put_line( i.li_xml.getclobval() );
dbms_output.put_line('<tns:lines>');
-- Lines section
for x in (select xmlelement("tns:line_num", line_num)
,xmlelement("tns:order", order_dtl)
,xmlelement("tns:qty", qty)
from Lines_tbl) lx loop
dbms_output.put_line( x.lx_xml.getclobval() );
dbms_output.put_line('<tns:Summary>');
-- Summary section
for y in (select xmlelement("tns:sum_num", sum_num)
,xmlelement("tns:total_amt, total_amt)
,xmlelement("tns:total_qty, total_qty)
from Summary_Tbl) lc_xml loop
dbms_output.put_line( y.lc_xml.getclobval() );
end loop;
dbms_output.put_line('<tns:Summary>');
dbms_output.put_line('</tns:lines>');
end loop;
end loop;
dbms_output.put_line('</tns:jpk>');
end;
the above sample code looks like this:
<tns:jpk>
<tns:header>1</tns:header>
<tns:customer>1000</tns:customer>
<tns:po_number>909090</tns:po_number>
<tns:lines>
<tns:line_num>1</tns:line_num>
<tns:order>Other FA Open Asset Cost Pozostale Srodki Trwale -Wartosc poczatkowa</tns:order>
<tns:qty>1</tns:qty>
<tns:Summary>
<tns:sum_num>1</tns:sum_num>
<tns:total_amt>1000</tns:total_amt>
<tns:total_qty>1</tns:total_qty>
</tns:Summary>
</tns:lines>
</tns:jpk>
I've managed to make it a bit faster by using a different approach, like the code below:
declare
xml_c xmltype;
procedure print_clob( p_clob in clob ) is
v_offset number := 1;
v_chunk_size number := 10000;
--v_chunk_size number := 32767;
begin
loop
exit when v_offset > dbms_lob.getlength(p_clob);
dbms_output.put_line( dbms_lob.substr( p_clob, v_chunk_size, v_offset ) );
v_offset := v_offset + v_chunk_size;
end loop;
EXCEPTION
WHEN OTHERS THEN
dbms_output.put_line('print_clob. others ' || SQLERRM);
end print_clob;
begin
select xmlagg(xmlconcat("<tns:jpk>",
-- header section
(select xmlagg(xmlconcat(
xmlelement("tns:header", header_num)
,xmlelement("tns:customer", customer_name)
,xmlelement("tns:po_number", po_number)
,xmlelement("tns:lines",
-- lines section
,(select
xmlagg(xmlconcat(
xmlelement("tns:line_num", line_num)
, xmlelement("tns:order", order_dtl)
, xmlelement("tns:qty", qty)
, (select
xmlagg(xmlconcat(
xmlelement("tns:sum_num", sum_num)
, xmlelement("tns:total_amt", total_amt)
, xmlelement("tns:total_qty", total_qty)))
from Summary_Tbl)
))
from Lines_tbl)
)
))
from header_tbl)
))
into xml_c
from dual;
print_clob( xml_c.getclobval );
end;
The above code makes a really long XML, and cuts it up to pieces and prints it.
It works fine and faster based on the execution times.
However, whenever there's a really long piece of string, the output sometimes gets skwered like below:
<tns:jpk>
<tns:header>1</tns:header>
<tns:customer>1000</tns:customer>
<tns:po_number>909090</tns:po_number>
<tns:lines>
<tns:line_num>1</tns:line_num>
<tns:order>Other FA Open Asset Cost Pozostale
Srodki Trwale -Wartosc poczatkowa</tns:order>
<tns:qty>1</tns:qty>
<tns:Summary>
<tns:sum_num>1</tns:sum_num>
<tns:total_amt>1000</tns:total_amt>
<tns:total_qty>1</tns:total_qty>
</tns:Summary>
</tns:lines>
</tns:jpk>
Is there a way for me to find out if the tag and it's contents will exceed the limit before I print it?