Ora-28509 and ora-28511 when attempting to join oracle with postgresql in query

Question

I have attempted to run the following statement.
select a."uri", b.person_id from "sources"@postgresql a, ct_person_src_ref_store b where decoder(b.source_uri) = a."id";
This is the error I get.
ERROR at line 1:
ORA-28511: lost RPC connection to heterogeneous remote agent using
SID=ORA-28511: lost RPC connection to heterogeneous remote agent using
SID=(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521))(CONNECT_DAT
A=(SID=posgre133)))
ORA-28509: unable to establish a connection to non-Oracle system
ORA-02063: preceding line from POSTGRESQL
Process ID: 116908
Session ID: 5197 Serial number: 49491
I have a resulting trace file from having HS_FDS_TRACE_LEVEL = DEBUG.  It's kind of long (490 lines).  I'm hesitant to paste the whole log into this posting. Is there a certain part of the trace file that I can post that would assist in helping me determine the cause of the error?
Thanks

Answer 1

That works now ....
When we ask the Postgres driver which columns/data types are in that table it reports:
Entered hgopcda at 2014/04/16-20:59:52
Column:27(uri): dtype:-1 (LONGVARCHAR), prc/scl:8190/0, nullbl:1, octet:0, sign:1, radix:10
Exiting hgopcda, rc=0 at 2014/04/16-20:59:52
Which then leads to:
SQL text from hgopars, id=1, len=32 ...
     00: 53454C45 43542022 6964222C 22757269  [SELECT "id","uri]
     10: 22204652 4F4D2022 736F7572 63657322  [" FROM "sources"]
Column:1(id): dtype:-5 (BIGINT), prc/scl:19/0, nullbl:0, octet:0, sign:1, radix:0
Exiting hgopcda, rc=0 at 2014/04/16-21:05:15
Entered hgopcda at 2014/04/16-21:05:15
Column:2(uri): dtype:-1 (LONGVARCHAR), prc/scl:8190/0, nullbl:1, octet:8190, sign:1, radix:0
Exiting hgopcda, rc=0 at 2014/04/16-21:05:15
hgodscr, line 464: Printing hoada @ 0x1ab8820
MAX:2, ACTUAL:2, BRC:1, WHT=5 (SELECT_LIST)
hoadaMOD bit-values found (0x20:NEGATIVE_HOADADTY,0x200:TREAT_AS_CHAR)
DTY             NULL-OK  LEN  MAXBUFLEN   PR/SC  CST IND MOD NAME
-5 BIGINT      N          8          8   0/  0    0   0  20 id
-1 LONGVARCHAR Y          0          0   0/  0    0   0 220 uri
Exiting hgodscr, rc=0 at 2014/04/16-21:05:15
=> so far so good. The gateway exists from that routine and here it can't locate the database process anymore:
Exiting hgodscr, rc=0 at 2014/04/16-21:05:15
HS Agent received unexpected RPC disconnect
   Network error 1004:  NCR-01004: NCRS: Write error.
Could you please upload the alert.log details matching that timstamp?
- Klaus