sporadic ora-3137 in direct mode using dbms_alert

[albourgz]

Hi,

using oracle 12.2 EE Rac, c++ builder XE10.2, unidac 7.4.12, vcl, direct mode.
Oracle console reports regular incidents on an ORA-3137, ~ once a day, and incidents are created on server.
Incindent trace file on the server shows:

Code: Select all

[TOC00000]
Jump to table of contents
Dump continued from file: /u01/app/oracle/diag/rdbms/giruis/GI1/trace/GI1_ora_22772.trc
[TOC00001]
ORA-03137: malformed TTC packet from client rejected: [3146] [94] [] [] [] [] [] []

[TOC00001-END]
[TOC00002]
========= Dump for incident 142373 (ORA 3137 [3146]) ========

*** 2019-07-14T06:50:01.025151+02:00
dbkedDefDump(): Starting incident default dumps (flags=0x2, level=3, mask=0x0)
[TOC00003]
----- Current SQL Statement for this session (sql_id=g3t80gzkdntkp) -----
begin DBMS_ALERT.WaitAny(:Name, :Message, :Status, :TimeOut); end;
[TOC00003-END]

And trace shows it comes from the .exe generated with unidac. DBMS_ALERT is used hundreds times a day, via component TUniAlerter, but some seem to fail.

Any hint?

[MaximG]

Does the issue persist when you use the OCI Mode with Oracle Client?

[albourgz]

I didn't try. We don't use oci client anymore, it is one of the advantages of unidac.

[MaximG]

For further investigation, please compose and send us a small full sample, execution of which causes the described error. It is convenient to do this via the e-support form (https://www.devart.com/company/contactform.html)