Comments on: How to calculate size of a CLOB in Bytes?

By: Kiran

Kiran — Fri, 06 Jan 2012 18:59:48 +0000

Hi Filippos,
what is the .getblobval which you are using in your query?

By: Filippos

Filippos — Wed, 07 Dec 2011 14:19:29 +0000

I ran into the same problem, albeit when trying to calculate the length of XMLTYPE contents.
Finally the solution was to write my own function that returns a such a CLOB that LENGTH would always give the correct value !
Just in case it is needed, I will provide my solution here :

create or replace
FUNCTION “BLOB_TO_CLOB” (p_blob IN BLOB) RETURN CLOB
AS

v_clob CLOB;
v_dest_offset INTEGER := 1;
v_source_offset INTEGER := 1;
v_lang_context INTEGER := DBMS_LOB.DEFAULT_LANG_CTX;
v_warning INTEGER := DBMS_LOB.WARN_INCONVERTIBLE_CHAR;

BEGIN

DBMS_LOB.CREATETEMPORARY(v_clob, TRUE);

DBMS_LOB.CONVERTTOCLOB
(
DEST_LOB => v_clob,
SRC_BLOB => p_blob,
AMOUNT => DBMS_LOB.LOBMAXSIZE,
DEST_OFFSET => v_dest_offset,
SRC_OFFSET => v_source_offset,
BLOB_CSID => DBMS_LOB.DEFAULT_CSID,
LANG_CONTEXT => v_lang_context,
WARNING => v_warning
);

RETURN v_clob;

END BLOB_TO_CLOB;

SELECT LENGTH(BLOB_TO_CLOB(.getBlobVal(NLS_CHARSET_ID(‘AL32UTF8″)))
FROM DUAL;

By: Quentin Crisp

Quentin Crisp — Wed, 21 Sep 2011 13:42:48 +0000

Thanks you are a life saver!

By: Peter Raganitsch

Peter Raganitsch — Mon, 20 Dec 2010 08:17:20 +0000

Steve,

is it important to know whether the resulting string contains multibyte characters?

To me it was enough to know, if the resulting string exceeds a certain length, no matter if there are multibyte characters in it, or not.

By: Steve

Steve — Sat, 18 Dec 2010 13:37:59 +0000

I still haven’t come up with a good way to determine if a CLOB > 4K contains any multibyte characters. I ran into many of the same limitations you did above. I ended up writing a java program that read each character and determined if its code point value was greater than 255. A really ugly hack.