Re: context index size

If you take all the defaults, that includes thematic reduction which takes up a lot more space. Unless, you need it, I might turn that feature off.   I believe the rule of thumb to start is 3X the text size that you are indexing. Over time that edges toward 1-1.

Merry XMAS

Tim
Lanham, MD

>Merry Christmas!
>
>Here I am using Oracle 8.1.6 on NT. I have a table to store XML
>documents, which has the the following columns:
>
>VALUE: XML data; (CLOB)
>PATH: path expression; (VARCHAR2)
>RPATH: reverse path expression; (VARCHAR2)
>
>Then, I create a context index, set the preference of user_datastore,
>which has a stored procedure to create index on mulitple columns: PATH,
>VALUE, and RPATH on the fly.
>
>The table has about 30,000 rows (very small XML data, 1k size). When
>the index is built, I found that 550MB was used by observing the disk
>usage from NT. However, if I simply create context index on the column
>VALUE, it would consume less than 10MB. or are there any tools to
>measure the index?
>
>Can anyone explain for me? Attached please find the procedure. Thank
>you!
>
>Honglin
>
>PS:
>
>create or replace procedure myproc
>(rid in rowid, tlob in out clob)
>is offset number:=1;
>v_value clob;
>v_path varchar2(128);
>v_rpath varchar2(128);
>
>begin
> if dbms_lob.istemporary(tlob) <> 1 then
> raise_application_error (-20000,
> '"IN OUT" tlob is not temporary');
> end if;
>
> select path, value, rpath into
> v_path, v_value, v_rpath
> from xmldocuments where rowid=rid;
>
> dbms_lob.trim (
> lob_loc => tlob,
> newlen => 0
> );
>
> dbms_lob.write (
> lob_loc => tlob,
> amount => length(v_path),
> offset => 1,
> buffer => v_path
> );
>
> if not (v_value is null or
> dbms_lob.getlength(v_value)<1)
> then
> dbms_lob.copy (
> dest_lob => tlob,
> src_lob => v_value,
> amount => dbms_lob.getlength(v_value),
> dest_offset => length(v_path) + 2,
> src_offset => 1
> );
> end if;
>
> dbms_lob.write (
> lob_loc => tlob,
> amount => length(v_rpath),
> offset => dbms_lob.getlength(tlob) + 2,
> buffer => v_rpath
> );
>end myproc;
>
>
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Received on Sun Dec 24 2000 - 07:33:14 CST