Structured XMLIndex is not being used

Question

I have a table defined as "TABLE OF XMLTYPE" with XML Binary storage with a structured XMLIndex under Oracle 11.2.0.3.4. The query that I am using on this table is virtually the same as the XMLIndex, but it's not being used. I searched the forums for similar issues and found this:
XMLIndex is not getting used
However, the post is a couple of years old, and I think that the solution was really specific to the problem. Not that mine isn't. ;)
Per the forum guidelines, the data/DDL is confidential, and should not be posted, so I opened a SR for it - SR 3-7160281751.
May I please have some help understanding why the structured XMLIndex is not being used?
Thanks...

Answer 1

OK, I did the best I could to clean this up. The last query in this script is the one not using the index. The tables "book_master" and "book_join_temp" are populated, though I didn't include the data here. Do you see anything wrong?
--Create tables...
CREATE TABLE book_master OF XMLTYPE
XMLTYPE STORE AS SECUREFILE BINARY XML
VIRTUAL COLUMNS
  isbn_nbr AS ( XmlCast(
                XmlQuery('declare namespace plh="http://www.mrbook.com/InventoryData/Listing";
                          declare namespace invtdata="http://www.mrbook.com/Inventory";
                          /invtdata:INVENTORY/plh:LIST/plh:ISBN_NBR'
                          PASSING object_value RETURNING CONTENT) AS VARCHAR2(64)) ),
  book_id AS ( XmlCast(
                XmlQuery('declare namespace plh="http://www.mrbook.com/InventoryData/Listing";
                          declare namespace invtdata="http://www.mrbook.com/Inventory";
                          /invtdata:INVENTORY/plh:LIST/plh:BOOK_ID'
                          PASSING object_value RETURNING CONTENT) AS VARCHAR2(64)) )
CREATE GLOBAL TEMPORARY TABLE book_join_temp
   isbn_nbr VARCHAR2(64),
   book_id VARCHAR2(64),
   row_num INT,
   PRIMARY KEY(row_num)
) ON COMMIT DELETE ROWS;
--Create indices....
CREATE INDEX bkm_xmlindex_ix ON book_master (OBJECT_VALUE) INDEXTYPE IS XDB.XMLIndex PARAMETERS ('PATH TABLE path_tab');
BEGIN
   DBMS_XMLINDEX.registerParameter(
      'myparam',
      'ADD_GROUP GROUP book_record
         XMLTable bk_idx_tab
         XmlNamespaces(''http://www.mrbook.com/InventoryData/Listing'' AS "plh",
                  ''http://www.mrbook.com/Inventory'' AS "invtdata",
                  ''http://www.mrbook.com/BookInfo'' AS "idty",
                  ''http://www.mrbook.com/References'' AS "lclone",
                  ''http://www.mrbook.com/Publishing'' AS "trd",
                  ''http://www.mrbook.com'' AS "mrbook"),
         ''/invtdata:INVT_DATA''
           COLUMNS
                xml_id    RAW(16)     PATH ''/@XML_ID'',
                isbn_nbr  VARCHAR(64) PATH ''/plh:LIST/plh:ISBN_NBR'',
                book_id   VARCHAR(64) PATH ''/plh:LIST/plh:BOOK_ID'',
                seller_loc_id NUMBER(13,0) PATH ''/plh:LIST/plh:SELLER_LOC_ID'',
                catg_typ_cd NUMBER(7,0) PATH ''/idty:BK_INFO/idty:CATG_TYP_CD'',
                CTRY_MKT_LOC NUMBER(7,0) PATH ''/idty:BK_INFO/idty:CTRY_MKT_LOC'',
                bk_out_of_print_cd NUMBER(7,0) PATH ''/idty:BK_INFO/idty:BK_OUT_OF_PRINT_CD'',
                reprint_isbn_nbr VARCHAR2(64) PATH ''/idty:BK_INFO/idty:REPRINT_ISBN_NBR'',
                reprint_book_id VARCHAR2(64) PATH ''/idty:BK_INFO/idty:REPRINT_BOOK_ID'',
                orig_ed_isbn_nbr VARCHAR2(64) PATH ''/lclone:REFERENCES/lclone:PRINT[child::lclone:PRINT_TYP_CD="160"]/lclone:ISBN_NBR'',
                orig_ed_book_id VARCHAR2(64) PATH ''//lclone:REFERENCES/lclone:PRINT[child::lclone:PRINT_TYP_CD="160"]/lclone:BOOK_ID'',
                last_mod_dt TIMESTAMP PATH ''/node()[local-name()="LAST_MOD_DT"]'',
                subject_catg_code  NUMBER(7) PATH ''/idty:BK_INFO/idty:SUBJECT_CATG_CODE[child::idty:CATG_REF_LVL=1]/idty:SUBJECT_CATG_CODE'',
                catg_code VARCHAR2(48) PATH ''/idty:BK_INFO/idty:SUBJECT_CATG_CODE[child::idty:CATG_REF_LVL=1]/idty:CATG_CODE'',
                pub_summ  XMLType   PATH ''/trd:PUB_SUMM'' VIRTUAL
            XMLTable trd_summ_entr_ix
            XmlNamespaces(''http://www.mrbook.com/InventoryData/Listing'' AS "plh",
                  ''http://www.mrbook.com/Inventory'' AS "invtdata",
                  ''http://www.mrbook.com/BookInfo'' AS "idty",
                  ''http://www.mrbook.com/References'' AS "lclone",
                  ''http://www.mrbook.com/Publishing'' AS "trd",
                  ''http://www.mrbook.com'' AS "mrbook"),
               ''/trd:PUB_SUMM/trd:PUBLC'' PASSING pub_summ
            COLUMNS
                pub_yrmo  VARCHAR2(6) PATH ''/@PUBLC_YRMO''
END;
ALTER INDEX bk_xmlindex_ix PARAMETERS('PARAM myparam');
CREATE INDEX ejt_isbn ON book_join_temp(isbn_nbr);
CREATE INDEX ejt_book ON book_join_temp(book_id);
--Using the PATH table instead of structured index???
SELECT
    ej.row_num,
    e.xml_id,
    e.isbn_nbr,
    e.book_id,
    e.seller_loc_id,
    e.seller_loc_id AS mkt_seller_id,
    e.catg_typ_cd,
    e.CTRY_MKT_LOC,
    e.bk_out_of_print_cd,
    e.reprint_isbn_nbr,
    e.reprint_book_id,
    e.orig_ed_isbn_nbr,
    e.orig_ed_book_id,
    g.OBJECT_VALUE AS invt_data
FROM
    book_master g,
    book_join_temp ej,
    XmlTable(
    XmlNamespaces('http://www.mrbook.com/InventoryData/Listing' AS "plh",
                  'http://www.mrbook.com/Inventory' AS "invtdata",
                  'http://www.mrbook.com/BookInfo' AS "idty",
                  'http://www.mrbook.com/References' AS "lclone",
                  'http://www.mrbook.com' AS "mrbook"),
      '/invtdata:INVENTORY'
    PASSING g.OBJECT_VALUE
    COLUMNS
       xml_id PATH '@XML_ID',
       isbn_nbr VARCHAR2(64) PATH 'plh:LIST/plh:ISBN_NBR',
       book_id VARCHAR2(64) PATH 'plh:LIST/plh:BOOK_ID',
       seller_loc_id NUMBER PATH 'plh:LIST/plh:SELLER_LOC_ID',
       catg_typ_cd NUMBER PATH 'idty:BK_INFO/idty:CATG_TYP_CD',
       CTRY_MKT_LOC NUMBER PATH 'idty:BK_INFO/idty:CTRY_MKT_LOC',
       bk_out_of_print_cd NUMBER PATH 'idty:BK_INFO/idty:BK_OUT_OF_PRINT_CD',
       reprint_isbn_nbr NUMBER PATH 'idty:SUBJ_DTL/idty:SUCSR_DUNS_NBR',
       reprint_book_id NUMBER PATH 'idty:SUBJ_DTL/idty:SUCSR_SUBJ_ID',
       orig_ed_isbn_nbr VARCHAR2(64) PATH '/lclone:REFERENCES/lclone:PRINT[child::lclone:PRINT_TYP_CD="160"]/lclone:ISBN_NBR',
       orig_ed_book_id VARCHAR2(64) PATH '/lclone:REFERENCES/lclone:PRINT[child::lclone:PRINT_TYP_CD="160"]/lclone:BOOK_ID'
) e
WHERE
     ej.isbn_nbr = e.isbn_nbr
OR  ej.book_id = e.book_id;