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Oracle 19c Client returns ORA-12637 when connecting to a 19c Database. Does not reproduce when using an older client version. (Doc ID 2662778.1)

Last updated on APRIL 17, 2023

Applies to:

Oracle Net Services - Version and later
Oracle Database - Enterprise Edition - Version to [Release 19]
Information in this document applies to any platform.


Sqlplus using a Version 19c client yield ORA-12637 when trying to connect to a 19c database.


SQL*Plus: Release - Production on Wed Apr 22 08:46:22 2020

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ORA-12637: Packet receive failed

Issue does not reproduce when using a Version 12 client

SQLNET level 16 Server tracing will show this as the point of failure

[23-APR-2020 15:28:01:125] nsaccept: Checking OOB Support
[23-APR-2020 15:28:01:125] sntpoltsts: fd 17 need 43 readiness event, wait time -1
[23-APR-2020 15:28:20:376] sntpoltsts: fd 17 has 2 readiness ev
[23-APR-2020 15:28:20:376] sntpoltsts: exit
[23-APR-2020 15:28:20:376] nttctl: entry
[23-APR-2020 15:28:20:376] ntt2err: entry
[23-APR-2020 15:28:20:376] ntt2err: soc 17 error - operation=5, ntresnt[0]=517, ntresnt[1]=104, ntresnt[2]=0
[23-APR-2020 15:28:20:376] ntt2err: exit
[23-APR-2020 15:28:20:376] nsaccept: OOB is getting dropped  
[23-APR-2020 15:28:20:376] nsprecv: entry
[23-APR-2020 15:28:20:376] nsprecv: reading from transport...
[23-APR-2020 15:28:20:376] nttrd: entry
[23-APR-2020 15:28:20:376] nttrd: exit
[23-APR-2020 15:28:20:376] ntt2err: entry
[23-APR-2020 15:28:20:376] ntt2err: Read unexpected EOF ERROR on 17
[23-APR-2020 15:28:20:376] ntt2err: exit
[23-APR-2020 15:28:20:376] nsprecv: error exit
[23-APR-2020 15:28:20:376] nserror: entry
[23-APR-2020 15:28:20:376] nserror: nsres: id=0, op=68, ns=12537, ns2=12560; nt[0]=507, nt[1]=0, nt[2]=0; ora[0]=0, ora[1]=0, ora[2]=0
[23-APR-2020 15:28:20:376] nsaccept: error exit
[23-APR-2020 15:28:20:376] nioqper:  error from niotns: nsaccept failed...
[23-APR-2020 15:28:20:376] nioqper:    ns main err code: 12537
[23-APR-2020 15:28:20:376] nioqper:    ns (2)  err code: 12560
[23-APR-2020 15:28:20:376] nioqper:    nt main err code: 507
[23-APR-2020 15:28:20:376] nioqper:    nt (2)  err code: 0
[23-APR-2020 15:28:20:376] nioqper:    nt OS   err code: 0
[23-APR-2020 15:28:20:376] niotns: No broken-connection function available.
[23-APR-2020 15:28:20:376] niomapnserror: entry
[23-APR-2020 15:28:20:376] niqme: entry
[23-APR-2020 15:28:20:376] niqme: reporting NS-12537 error as ORA-12537
[23-APR-2020 15:28:20:376] niqme: exit
[23-APR-2020 15:28:20:376] niomapnserror: exit
[23-APR-2020 15:28:20:376] niotns: Couldn't connect, returning 12537


 New Feature added to 19c. Client will trigger the server to test for OOB availability at connect time. If it fails the error is reported.


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