ORA-19011: Character string buffer too small

Question

I have written a stored procedure SP_DEMAND_QRY. This produces the correct value if there are only a few matching rows (5 or 6) in the Demand table. But if that table contains more matching rows (>6) then I get this error when I execute it:

Error:
-------
ORA-19011: Character string buffer too small
ORA-06512: at line 7

The procedure is:

create or replace PROCEDURE SP_DEMAND_QRY 
    (
      USR IN VARCHAR2  
    , OUT_CLOB OUT CLOB  
    ) AS 
BEGIN
    SELECT to_clob(XMLElement("DEMANDS",XMLAgg(XMLElement("Demand"
               ,XMLElement("DemandId",dmnd_id)
               ,XMLElement("CreatedBy",CREATED_BY)
               ,XMLElement("CreatedDate",CREATED_DATE)
               ,XMLElement("Designation",DESIGNATION)
               ,XMLElement("Experience",EXPERIENCE)
               ,XMLElement("PrimarySkill",PRIMARY_SKILL)
               ,XMLElement("SecondarySkill",SECONDARY_SKILL)
               ,XMLElement("OtherSkill",OTHER_SKILL)
               ,XMLElement("RequiredDate",REQUIRED_DATE)
               ,XMLElement("ProbablePercentage",PROBABLE_PERCENTAGE)
               ,XMLElement("CriticalFlag",CRITICAL_FLG)
               ,XMLElement("AssignedFlag",ASSIGNED_FLG)
               ,XMLElement("AccountName",ACCOUNT_NAME)
               ,XMLElement("OpportunityName",OPTY_NAME)
               ,XMLElement("AccountPOC",ACCNT_POC)
               ,XMLElement("COE",COE)
               ,XMLElement("DemandType",DEMAND_TYPE)
               ,XMLElement("Location",LOC)
               ,XMLElement("ExpectedRole",EXPECTED_ROLE)
               ,XMLElement("ConfidenceFactor",CONFIDENCE_FACTOR)
               ,XMLElement("EndDate",END_DT)
               ,XMLElement("HiringSO",HIRING_SO)
               ,XMLElement("HiringSOId",HIRING_SO_ID)
               ,XMLElement("Comments",COMMENTS)
           )))) 
    into OUT_CLOB
    from demand s
    where s.CREATED_BY=usr;
    --DBMS_output.put_line(OUT_CLOB);
END SP_DEMAND_QRY;

What am I doing wrong?

Answer 1

The to_clob() function takes a character value, so you have an implicit conversion from the XMLType returned by XMLElement() into varchar2; once the length of the XML exceed 4k (since you're in an SQL context) you'll get that error.

You can use the XMLType function getCLobVal() instead:

    SELECT XMLElement("DEMANDS",
                XMLAgg(XMLElement("Demand"
                            ,XMLElement( "DemandId",dmnd_id)
                        ,XMLElement( "CreatedBy",CREATED_BY)
...
    ,XMLElement("Comments",COMMENTS)
                       ))).getClobVal()
    into OUT_CLOB
    ...

So the outer call to to_clob() has been removed, and replaced with a call to XMLElement().getClobVal(). Verified with XML greater than 32k as well.