Shared Server: ORA-28547: Connection To Server Failed, Probable Oracle Net Admin Error (Doc ID 2425839.1)

Last updated on SEPTEMBER 01, 2023

Applies to:

Symptoms

The Oracle database is running in shared server mode.  Remote client connections are intermittently failing with the following error:

SQL>connect username@ORCL_shared
password:

SQL*Plus: Release 12.1.0.2.0 Production on Tue Jun 26 12:01:55 2018
Copyright 1982, 2014, Oracle. All rights reserved.
Enter password:
ERROR:
ORA-28547: connection to server failed, probable Oracle Net admin error

An Oracle Net level 16 Client trace reveals the underlying error is an ORA-00018.

(2364) [27-JUN-2018 15:42:39:346] nttfprd: entry
(2364) [27-JUN-2018 15:42:39:359] nttfprd: socket 420 had bytes read=92
(2364) [27-JUN-2018 15:42:39:359] nttfprd: exit
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: type=6, plen=92
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: what=1, tot =92
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: packet dump
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: 00 00 00 5C 06 20 00 00 |...\....|
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: 00 00 04 01 01 00 00 01 |........|
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: 12 00 00 00 00 00 00 00 |........|
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: 00 00 00 00 00 00 00 00 |........|
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: 00 00 02 00 00 00 00 00 |........|
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: 00 01 12 00 2F 4F 52 41 |..../ORA|
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: 2D 30 30 30 31 38 3A 20 |-00018:.|
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: 6D 61 78 69 6D 75 6D 20 |maximum.|
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: 6E 75 6D 62 65 72 20 6F |number.o|
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: 66 20 73 65 73 73 69 6F |f.sessio|
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: 6E 73 20 65 78 63 65 65 |ns.excee|
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: 64 65 64 0A |ded. |
(2364) [27-JUN-2018 15:42:39:359] nsbasic_brc: exit: oln=0, dln=82, tot=92, rc=0
(2364) [27-JUN-2018 15:42:39:359] nioqrc: exit
(2364) [27-JUN-2018 15:42:43:249] nioqds: entry
(2364) [27-JUN-2018 15:42:43:249] nioqds: disconnecting...
(2364) [27-JUN-2018 15:42:43:249] nsclose: entry
(2364) [27-JUN-2018 15:42:43:250] nsvntx_dei: entry
(2364) [27-JUN-2018 15:42:43:250] nsvntx_dei: exit
(2364) [27-JUN-2018 15:42:43:250] nstimarmed: entry

Set the following event in order to collect dispatcher traces:
SQL> alter system set events '10248 trace name context forever, level 10';

Allow this to collect long enough to capture the error then turn it off using:

SQL> alter system set events '10248 trace name context off';

dispatcher trace reveals ORA 18:
*** 2018-06-30 03:38:06.193 nsevwait: got 1 event(s) nsevwait: got 1 event(s) EVENTS: cxd (0xffffffff75d9dd68), events(0x20) nsevwait: got 1 event(s) EVENTS: cxd (0xffffffff75d9dd68), events(0x20)
*** 2018-06-30 03:38:06.196 error 18 creating virtual circuit
*** 2018-06-30 03:38:13.324 nsevwait: got 1 event(s) nsevwait: got 1 event(s) EVENTS: cxd (0xffffffff75d9dd68), events(0x20) nsevwait: got 1 event(s) EVENTS: cxd (0xffffffff75d9dd68), events(0x20)
*** 2018-06-30 03:38:13.326 error 18 creating virtual circuit
*** 2018-06-30 03:38:41.038 error 18 creating virtual circuit

Changes

There are no recent changes to this environment.  There may have been an increase in client traffic to the instance running
in shared server mode since the error indicates a resource depletion.

Cause

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