How to improve performance of a query that is based on an xmltype table

Question

Dear Friends,
I have a query that is pulling records from an xmltype table with 9000 rows and it is running very slow.
I am using XMLTABLE command to retreive the rows. It is taking upto 30 minutes to finish.
Would you be able to suggest how I can make it faster. Thanks.
Below is the query.....
INSERT INTO temp_sap_po_receipt_history_t
(po_number, po_line_number, doc_year,
material_doc, material_doc_item, quantity, sap_ref_doc_no_long,
reference_doc, movement_type_code,
sap_ref_doc_no, posting_date, entry_date, entry_time, hist_type)
SELECT :pin_po_number po_number,
b.po_line_number, b.doc_year,
b.material_doc, b.material_doc_item, b.quantity, b.sap_ref_doc_no_long,
b.reference_doc, b.movement_type_code,
b.sap_ref_doc_no, to_date(b.posting_date,'rrrr-mm-dd'),
to_date(b.entry_date,'rrrr-mm-dd'), b.entry_time, b.hist_type
FROM temp_xml t,
XMLTABLE(XMLNAMESPACES('urn:sap-com:document:sap:rfc:functions' AS "n0"),
'/n0:BAPI_PO_GETDETAIL1Response/POHISTORY/item'
PASSING t.object_value
COLUMNS PO_LINE_NUMBER VARCHAR2(20) PATH 'PO_ITEM',
DOC_YEAR varchar2(4) PATH 'DOC_YEAR',
MATERIAL_DOC varchar2(30) PATH 'MAT_DOC',
MATERIAL_DOC_ITEM VARCHAR2(10) PATH 'MATDOC_ITEM',
QUANTITY NUMBER(20,6) PATH 'QUANTITY',
SAP_REF_DOC_NO_LONG VARCHAR2(20) PATH 'REF_DOC_NO_LONG',
REFERENCE_DOC VARCHAR2(20) PATH 'REF_DOC',
MOVEMENT_TYPE_CODE VARCHAR2(4) PATH 'MOVE_TYPE',
SAP_REF_DOC_NO VARCHAR2(20) PATH 'REF_DOC_NO',
POSTING_DATE VARCHAR2(10) PATH 'PSTNG_DATE',
ENTRY_DATE VARCHAR2(10) PATH 'ENTRY_DATE',
ENTRY_TIME VARCHAR2(8) PATH 'ENTRY_TIME',
HIST_TYPE VARCHAR2(5) PATH 'HIST_TYPE') b;

Answer 1

Based on response from mdrake on this thread:
Re: XML file processing into oracle
For large XML's, you can speed up the processing of XMLTABLE by using a registered schema...
declare
  SCHEMAURL VARCHAR2(256) := 'http://xmlns.example.org/xsd/testcase.xsd';
  XMLSCHEMA VARCHAR2(4000) := '<?xml version="1.0" encoding="UTF-8"?>
     <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xdb="http://xmlns.oracle.com/xdb" xdb:storeVarrayAsTable="true">
        <xs:element name="cust_order" type="cust_orderType" xdb:defaultTable="CUST_ORDER_TBL"/>
        <xs:complexType name="groupType" xdb:maintainDOM="false">
                <xs:sequence>
                        <xs:element name="item" type="itemType" maxOccurs="unbounded"/>
                </xs:sequence>
                <xs:attribute name="id" type="xs:byte" use="required"/>
        </xs:complexType>
        <xs:complexType name="itemType" xdb:maintainDOM="false">
                <xs:simpleContent>
                        <xs:extension base="xs:string">
                                <xs:attribute name="id" type="xs:short" use="required"/>
                                <xs:attribute name="name" type="xs:string" use="required"/>
                        </xs:extension>
                </xs:simpleContent>
        </xs:complexType>
        <xs:complexType name="cust_orderType" xdb:maintainDOM="false">
                <xs:sequence>
                        <xs:element name="group" type="groupType" maxOccurs="unbounded"/>
                </xs:sequence>
                <xs:attribute name="cust_id" type="xs:short" use="required"/>
        </xs:complexType>
     </xs:schema>';
  INSTANCE  CLOB :=
'<cust_order cust_id="12345">
  <group id="1">
    <item id="1" name="Standard Mouse">100</item>
    <item id="2" name="Keyboard">100</item>
    <item id="3" name="Memory Module 2Gb">200</item>
    <item id="4" name="Processor 3Ghz">25</item>
    <item id="5" name="Processor 2.4Ghz">75</item>
  </group>
  <group id="2">
    <item id="1" name="Graphics Tablet">15</item>
    <item id="2" name="Keyboard">15</item>
    <item id="3" name="Memory Module 4Gb">15</item>
    <item id="4" name="Processor Quad Core 2.8Ghz">15</item>
  </group>
  <group id="3">
    <item id="1" name="Optical Mouse">5</item>
    <item id="2" name="Ergo Keyboard">5</item>
    <item id="3" name="Memory Module 2Gb">10</item>
    <item id="4" name="Processor Dual Core 2.4Ghz">5</item>
    <item id="5" name="Dual Output Graphics Card">5</item>
    <item id="6" name="28inch LED Monitor">10</item>
    <item id="7" name="Webcam">5</item>
    <item id="8" name="A3 1200dpi Laser Printer">2</item>
  </group>
</cust_order>';                
begin
  dbms_xmlschema.registerSchema
     schemaurl       => SCHEMAURL
    ,schemadoc       => XMLSCHEMA
    ,local           => TRUE
    ,genTypes        => TRUE
    ,genBean         => FALSE
    ,genTables       => TRUE
    ,ENABLEHIERARCHY => DBMS_XMLSCHEMA.ENABLE_HIERARCHY_NONE
  execute immediate 'insert into CUST_ORDER_TBL values (XMLTYPE(:INSTANCE))' using INSTANCE;
end;
SQL> desc CUST_ORDER_TBL
Name                                                                                                                                    Null?    Type
TABLE of SYS.XMLTYPE(XMLSchema "http://xmlns.example.org/xsd/testcase.xsd" Element "cust_order") STORAGE Object-relational TYPE "cust_orderType222_T"
SQL> set autotrace on explain
SQL> set pages 60 lines 164 heading on
SQL> col cust_id format a8
SQL> select extract(object_value,'/cust_order/@cust_id') as cust_id
  2        ,grp.id as group_id, itm.id as item_id, itm.inm as item_name, itm.qty as item_qty
  3  from   CUST_ORDER_TBL
  4        ,XMLTABLE('/cust_order/group'
  5                  passing object_value
  6                  columns id   number       path '@id'
  7                         ,item xmltype      path 'item'
  8                 ) grp
  9        ,XMLTABLE('/item'
10                  passing grp.item
11                  columns id   number       path '@id'
12                         ,inm  varchar2(30) path '@name'
13                         ,qty  number       path '.'
14                 ) itm
15  /
CUST_ID    GROUP_ID    ITEM_ID ITEM_NAME                        ITEM_QTY
12345             1          1 Standard Mouse                        100
12345             1          2 Keyboard                              100
12345             1          3 Memory Module 2Gb                     200
12345             1          4 Processor 3Ghz                         25
12345             1          5 Processor 2.4Ghz                       75
12345             2          1 Graphics Tablet                        15
12345             2          2 Keyboard                               15
12345             2          3 Memory Module 4Gb                      15
12345             2          4 Processor Quad Core 2.8Ghz             15
12345             3          1 Optical Mouse                           5
12345             3          2 Ergo Keyboard                           5
12345             3          3 Memory Module 2Gb                      10
12345             3          4 Processor Dual Core 2.4Ghz              5
12345             3          5 Dual Output Graphics Card               5
12345             3          6 28inch LED Monitor                     10
12345             3          7 Webcam                                  5
12345             3          8 A3 1200dpi Laser Printer                2
17 rows selected.Need at least 10.2.0.3 for performance i.e. to avoid COLLECTION ITERATOR PICKLER FETCH in execution plan...
On 10.2.0.1:
Execution Plan
Plan hash value: 3741473841
| Id  | Operation                          | Name                   | Rows  | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT                   |                        | 24504 |    89M|   873   (1)| 00:00:11 |
|   1 |  NESTED LOOPS                      |                        | 24504 |    89M|   873   (1)| 00:00:11 |
|   2 |   NESTED LOOPS                     |                        |     3 | 11460 |   805   (1)| 00:00:10 |
|   3 |    TABLE ACCESS FULL               | CUST_ORDER_TBL         |     1 |  3777 |     3   (0)| 00:00:01 |
|*  4 |    INDEX RANGE SCAN                | SYS_IOT_TOP_774117     |     3 |   129 |     1   (0)| 00:00:01 |
|   5 |   COLLECTION ITERATOR PICKLER FETCH| XMLSEQUENCEFROMXMLTYPE |       |       |            |       |
Predicate Information (identified by operation id):
   4 - access("NESTED_TABLE_ID"="CUST_ORDER_TBL"."SYS_NC0000900010$")
       filter("SYS_NC_TYPEID$" IS NOT NULL)
Note
   - dynamic sampling used for this statementOn 10.2.0.3:
Execution Plan
Plan hash value: 1048233240
| Id  | Operation               | Name              | Rows  | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT        |                   |    17 |   132K|   839   (0)| 00:00:11 |
|   1 |  NESTED LOOPS           |                   |    17 |   132K|   839   (0)| 00:00:11 |
|   2 |   MERGE JOIN CARTESIAN  |                   |    17 |   131K|   805   (0)| 00:00:10 |
|   3 |    TABLE ACCESS FULL    | CUST_ORDER_TBL    |     1 |  3781 |     3   (0)| 00:00:01 |
|   4 |    BUFFER SORT          |                   |    17 | 70839 |   802   (0)| 00:00:10 |
|*  5 |     INDEX FAST FULL SCAN| SYS_IOT_TOP_56154 |    17 | 70839 |   802   (0)| 00:00:10 |
|*  6 |   INDEX UNIQUE SCAN     | SYS_IOT_TOP_56152 |     1 |    43 |     2   (0)| 00:00:01 |
|*  7 |    INDEX RANGE SCAN     | SYS_C006701       |     1 |       |     0   (0)| 00:00:01 |
Predicate Information (identified by operation id):
   5 - filter("SYS_NC_TYPEID$" IS NOT NULL)
   6 - access("SYS_NTpzENS1H/RwSSC7TVzvlqmQ=="."NESTED_TABLE_ID"="SYS_NTnN5b8Q+8Txi9V
              w5Ysl6x9w=="."SYS_NC0000600007$")
       filter("SYS_NC_TYPEID$" IS NOT NULL AND
              "NESTED_TABLE_ID"="CUST_ORDER_TBL"."SYS_NC0000900010$")
   7 - access("SYS_NTpzENS1H/RwSSC7TVzvlqmQ=="."NESTED_TABLE_ID"="SYS_NTnN5b8Q+8Txi9V
              w5Ysl6x9w=="."SYS_NC0000600007$")
Note
   - dynamic sampling used for this statement----------------------------------------------------------------------------------------------------------
-- CLEAN UP
DROP TABLE CUST_ORDER_TBL purge;
exec dbms_xmlschema.deleteschema('http://xmlns.example.org/xsd/testcase.xsd');