While attempting to generate an explain plan in an R12 Vision database, I instead generated the following error:
APPS@R12VIS(11.1.0.7)>set autotrace traceonly explain
APPS@R12VIS(11.1.0.7)>select count(*) from DUAL;
Execution Plan
----------------------------------------------------------
ERROR: an uncaught error in function display has happened; please contact Oracle support
Please provide also a DMP file of the used plan table PLAN_TABLE
ORA-00904: "OTHER_TAG": invalid identifier
Well, okay, I wasn't really querying the DUAL table, but it makes the example shorter. Since this was only happening when I was connected as the APPS user, I suspected a private PLAN_TABLE had been created for APPS, and sure enough:
APPS@r12vis(11.1.0.7)>select owner 2 , object_name 3 , object_type 4 from dba_objects 5 where object_name like 'PLAN_TABLE%'; OWNER OBJECT_NAME OBJECT_TYPE --------------- ------------------------------ -------------------- SYS PLAN_TABLE$ TABLE PUBLIC PLAN_TABLE SYNONYM APPS PLAN_TABLE TABLE
It's not too unusual to have a private PLAN_TABLE in a schema, even in a post-9i database. Oracle has definitely kept utlxplan.sql up to date in 11g. What was surprising to me was the structure of the table:
APPS@r12vis(11.1.0.7)>desc plan_table; Name Null? Type ----------------------------------------------------------------- -------- -------------------------------------------- STATEMENT_ID VARCHAR2(30) TIMESTAMP DATE REMARKS VARCHAR2(80) OPERATION VARCHAR2(30) OPTIONS VARCHAR2(30) OBJECT_NODE VARCHAR2(128) OBJECT_OWNER VARCHAR2(30) OBJECT_NAME VARCHAR2(30) OBJECT_INSTANCE NUMBER(38) OBJECT_TYPE VARCHAR2(30) SEARCH_COLUMNS NUMBER(38) ID NUMBER(38) PARENT_ID NUMBER(38) POSITION NUMBER(38) OTHER LONG
There are a lot of fields missing from that table. A quick reference check reveals that this is not a 9i version of the PLAN_TABLE, not even an 8i version, but a vintage Oracle 7.3 PLAN_TABLE. This is actually pretty cool, since it implies that Oracle's been eating its own dog food with respect to upgrading its demo instance. The Vision database clearly has a long and storied history. 
The solution to my original problem, of course, is to just drop the old plan table. If you'd rather keep a static PLAN_TABLE around for the APPS schema, it's still a good idea to drop it and recreate it with the 11g utlxplan.sql.
