Tag: Oracle 11gR2

Oracle | Single listener for multiple versions of database

On By windows7bugsIn Oracle database 11g, Oracle Database 19c, WindowsLeave a comment

Environment: Windows OS (Windows 11)

Currently I’ve 2 different versions of Oracle database installed & instances running from my development machine. Oracle 11G R2 (11.20.4) and Oracle 19c (19.14) & yes, we are supported by Oracle. I had 11G installed first & later installed 19c for checking out APEX and ORDS.

As 11G listener was running, I didn’t notice anything problematic until, tried to connect as a specific user. I started getting the error that the listener doesn’t know of the service name. 

PS D:\Oracle19c> sqlplus / as sysdba

SQL*Plus: Release 19.0.0.0.0 - Production on Thu Jan 12 12:45:30 2023
Version 19.14.0.0.0

Copyright (c) 1982, 2021, Oracle.  All rights reserved.


Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.14.0.0.0

SQL> quit
Disconnected from Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.14.0.0.0
PS D:\Oracle19c> sqlplus system@SCTCDB

SQL*Plus: Release 19.0.0.0.0 - Production on Thu Jan 12 12:45:34 2023
Version 19.14.0.0.0

Copyright (c) 1982, 2021, Oracle.  All rights reserved.

Enter password:
ERROR:
ORA-12514: TNS:listener does not currently know of service requested in connect
descriptor


Enter user-name:

I went ahead and using netca registered the 19c service with 11g listener, restarted the listener services and this time instead of complaining about the missing service, connection attempt froze.

After some confusion, I decided to drop the 11g listener services and created a new listener from 19c environment.

Registered both 19c & 11g services using 19c NETCA this time & restarted the listener. I was able to connect to both databases using username/password@servicename syntax this time.

So let us see what went wrong. 11g database was configured for connections from Oracle Developer 6i legacy applications.

This cannot be modified without failing the legacy application. Please refer the below to understand how the authentication works with different versions of databases and what has changed.

Check for the SQLNET.ALLOWED_LOGON_VERSION Parameter Behavior (oracle.com)

As I am not allowed to change 11g environment, the ONLY one way I can use the same listener was to register 11g service with 19c listener. Simple, clean and effective. Hope this helps few out there who is not a certified DBA like me ;)

Oracle | Thread 1 cannot allocate new log, Private strand flush not complete

On By windows7bugsIn NOT a DBA, Oracle database 11g, Oracle database 12cLeave a comment

Hello guys

Okay, I was silent for couple of months. I took a much needed break and back to work now. As few of you may already know, I am not a DBA (Certified), yet I have dealt with Oracle databases throughout my career & today was “another day” when I came across something new after restoring RMAN backup to a TEST environment.

Actually the entire “how to document” was provided by a APPS DBA friend (thanks to such geeks who are never bothered about someone else “learning the tricks” and challenging them! Geeks remain geeks) & without giving much attention to few elements, I “successfully” duplicated the 11g R2 database. Once after the database came online, I realized that the instance was pretty slow & immediately monitored the alert logs.

I started reading few entries like following:

Thread 1 cannot allocate new log, sequence 56
Private strand flush not complete
  Current log# 3 seq# 55 mem# 0: /u01/oratest/TEST/db/apps_st/data/redo03a.log
  Current log# 3 seq# 55 mem# 1: /u01/oratest/TEST/db/apps_st/data/redo03b.log
Beginning log switch checkpoint up to RBA [0x38.2.10], SCN: 5986177240123
Thread 1 advanced to log sequence 56 (LGWR switch)
  Current log# 4 seq# 56 mem# 0: /u01/oratest/TEST/db/apps_st/data/redo04a.log
  Current log# 4 seq# 56 mem# 1: /u01/oratest/TEST/db/apps_st/data/redo04b.log
Completed checkpoint up to RBA [0x38.2.10], SCN: 5986177240123
Thu Oct 04 12:14:14 2018
Beginning log switch checkpoint up to RBA [0x39.2.10], SCN: 5986177240998
Thread 1 advanced to log sequence 57 (LGWR switch)
  Current log# 1 seq# 57 mem# 0: /u01/oratest/TEST/db/apps_st/data/redo01a.log
  Current log# 1 seq# 57 mem# 1: /u01/oratest/TEST/db/apps_st/data/redo01b.log
Thread 1 cannot allocate new log, sequence 58
Private strand flush not complete
  Current log# 1 seq# 57 mem# 0: /u01/oratest/TEST/db/apps_st/data/redo01a.log
  Current log# 1 seq# 57 mem# 1: /u01/oratest/TEST/db/apps_st/data/redo01b.log
Thu Oct 04 12:14:25 2018
Beginning log switch checkpoint up to RBA [0x3a.2.10], SCN: 5986177241136
Thread 1 advanced to log sequence 58 (LGWR switch)
  Current log# 2 seq# 58 mem# 0: /u01/oratest/TEST/db/apps_st/data/redo02a.log
  Current log# 2 seq# 58 mem# 1: /u01/oratest/TEST/db/apps_st/data/redo02b.log
Thu Oct 04 12:14:47 2018
Thread 1 cannot allocate new log, sequence 59

I landed over a discussion at https://community.oracle.com/thread/364032?start=0&tstart=0 & few others, and at many places I read suggestions towards the redo log files getting filled too fast because of the smaller sizes allocated. I check the production instance, the redo log files were of size 1000M when the TEST instance log files were of size 100M!

So my next requirement was to resize the redo log files without damaging the database.

I came across an excellent post here https://uhesse.com/2010/01/20/how-to-change-the-size-of-online-redologs/ that explains how to create new redo log files and to drop the old ones without affecting the database (or users). The best part is, you don’t even have to take the database offline for any of the suggested activities.

So if you ever face such a situation, give it a try. You would be happy like me :)

regards,

rajesh