Buffered LOB_APPEND

Jens Ulrik asked to see the code for a buffered LOB_APPEND mentioned in an earlier post LOB_APPEND eats resources....

Here it is as part of a package. Apologies for the rush job at the time; inelegant, but it was worth it...

    gi_chunk_length integer := 0;
    gv_chunk varchar2(32767);

    -- add a character value to the CLOB being built up; catch null values
  -- NOTE - final flush is done elsewhere
  --        and we assume max(length(av_value))  < ki_maxchunksize

    PROCEDURE lob_append (at_doc_clob IN OUT NOCOPY CLOB, av_value IN VARCHAR2)
    IS
     li_value_length integer;
    li_new_chunk_length integer;
    ki_maxchunksize constant integer := 32000;
    BEGIN
        -- prt_common_pkg.print_xml_string(av_value);
        IF av_value IS NOT NULL THEN
        li_value_length := length(av_value);
    li_new_chunk_length := gi_chunk_length + li_value_length;
        
    if li_new_chunk_length >= ki_maxchunksize 
    then
      -- pad out the chunk as much as possible
      gv_chunk := gv_chunk || substr(av_value,1,ki_maxchunksize - gi_chunk_length);
      -- write out
      DBMS_LOB.append (at_doc_clob, gv_chunk);
      -- initialise remainder into next chunk
      gi_chunk_length := li_new_chunk_length - ki_maxchunksize;
      gv_chunk := substr(av_value,li_value_length +1 - gi_chunk_length);
    else
      gv_chunk := gv_chunk || av_value;
      gi_chunk_length := li_new_chunk_length;
    end if;
        ELSE
            prt_common_pkg.LOG ('lob_append null ignored',
                                prt_common_pkg.klog_ret
                               );
        END IF;
    END;

The final flush of the last chunk of a LOB is called like this:

    
    IF gi_chunk_length > 0 THEN
       -- flush out the last chunk of the CLOB
     dbms_lob.append(at_doc_clob, gv_chunk);
     gi_chunk_length := 0;
     gv_chunk := null;
    END IF;