DRG-11110: matches does not support functional invocation

Question

Hi all,
We are working on the some prototype and we hit this road block.
When 'matches' was included with other conditions in query and used in pl/sql we are getting this error.
Oracle Text error: DRG-11110: matches does not support functional invocation
We tried including the hint /*+ index(t2 t2x) */ * (t2 table and t2x index ) in query but it didn't help.
The query works fine from SQL developer, but included in pl/sql gives the error 9 out of 10times.
Is there something that anyone can help
Regards,
Chaitanya.

Answer 1

The optimizer tends to choose functional invocation, which will cause the query to fail, when the structured portion of the query is most restrictive. So you will need to stop it from selecting what might otherwise be the most efficient plan at the times when you might have otherwise gained the most performance benefit from it. You want to try to force the optimizer to use the domain index to select the rows based on the matches criteria first, then evaluate the other conditions. You will need to experiment with things like your date filter to see if that causes funcitonal invocation or not. It will depend on how restricitve that is, whether there is an index on the date column and whether there is a small enough amount of data to do a full table scan benficially. You might benefit from hints but the "rownum > 0" seems to have the most consistent effect. You can use "explain plan for" on a query that fails to see what it was trying to do. Notice the difference in the execution plans below for the first failed query and the second working query that uses the domain index.
SCOTT@orcl_11g> SET AUTOTRACE ON EXPLAIN
SCOTT@orcl_11g> SELECT req_id, request, query_id, query_string
  2  FROM   queries, requests, tmptab
  3  WHERE  matches (query_string, request) > 0
  4  AND    tmptab.ID = query_id
  5  /
SELECT req_id, request, query_id, query_string
ERROR at line 1:
ORA-20000: Oracle Text error:
DRG-11110: matches does not support functional invocation
SCOTT@orcl_11g> SET AUTOTRACE OFF
SCOTT@orcl_11g> EXPLAIN PLAN FOR
  2  SELECT req_id, request, query_id, query_string
  3  FROM   queries, requests, tmptab
  4  WHERE  matches (query_string, request) > 0
  5  AND    tmptab.ID = query_id
  6  /
Explained.
SCOTT@orcl_11g> SELECT * FROM TABLE (DBMS_XPLAN.DISPLAY)
  2  /
PLAN_TABLE_OUTPUT
Plan hash value: 3854985881
| Id  | Operation           | Name     | Rows  | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT    |          |     1 |   855 |    13   (8)| 00:00:01 |
|   1 |  NESTED LOOPS       |          |     1 |   855 |    13   (8)| 00:00:01 |
|*  2 |   HASH JOIN         |          |     3 |  1320 |     7  (15)| 00:00:01 |
|   3 |    TABLE ACCESS FULL| TMPTAB   |     3 |    39 |     3   (0)| 00:00:01 |
|   4 |    TABLE ACCESS FULL| QUERIES  |   300 |   125K|     3   (0)| 00:00:01 |
|*  5 |   TABLE ACCESS FULL | REQUESTS |     1 |   415 |     2   (0)| 00:00:01 |
Predicate Information (identified by operation id):
   2 - access("TMPTAB"."ID"="QUERY_ID")
   5 - filter("CTXSYS"."MATCHES"("QUERY_STRING","REQUEST")>0)
Note
   - dynamic sampling used for this statement
22 rows selected.
SCOTT@orcl_11g> DELETE plan_table
  2  /
6 rows deleted.
SCOTT@orcl_11g> SET AUTOTRACE ON EXPLAIN
SCOTT@orcl_11g> SELECT req_id, request, query_id, query_string
  2  FROM   (SELECT req_id, request, query_id, query_string
  3            FROM   queries, requests
  4            WHERE  matches (query_string, request) > 0
  5            AND    ROWNUM > 0),
  6           tmptab
  7  WHERE tmptab.ID = query_id
  8  /
    REQ_ID REQUEST           QUERY_ID QUERY_STRING
         1 A B C                  699 A | B
         2 B C                    699 A | B
Execution Plan
Plan hash value: 615182442
| Id  | Operation                        | Name             | Rows  | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT                 |                  |    45 | 37935 |    14   (8)| 00:00:01 |
|*  1 |  HASH JOIN                       |                  |    45 | 37935 |    14   (8)| 00:00:01 |
|   2 |   TABLE ACCESS FULL              | TMPTAB           |     3 |    39 |     3   (0)| 00:00:01 |
|   3 |   VIEW                           |                  |    45 | 37350 |    10   (0)| 00:00:01 |
|   4 |    COUNT                         |                  |       |       |            |          |
|*  5 |     FILTER                       |                  |       |       |            |          |
|   6 |      NESTED LOOPS                |                  |    45 | 37890 |    10   (0)| 00:00:01 |
|   7 |       TABLE ACCESS FULL          | REQUESTS         |     3 |  1245 |     3   (0)| 00:00:01 |
|   8 |       TABLE ACCESS BY INDEX ROWID| QUERIES          |    15 |  6405 |    10   (0)| 00:00:01 |
|*  9 |        DOMAIN INDEX              | QUERY_STRING_IDX |       |       |     0   (0)| 00:00:01 |
Predicate Information (identified by operation id):
   1 - access("TMPTAB"."ID"="QUERY_ID")
   5 - filter(ROWNUM>0)
   9 - access("CTXSYS"."MATCHES"("QUERY_STRING","REQUEST")>0)
Note
   - dynamic sampling used for this statement
SCOTT@orcl_11g>