Oracle FMW GoldenGate Veridata setup OUI troubles with X Server

I have spent several hours finding the reason why installation of Oracle GoldenGate Veridata 12.2.1 on RedHad Enterpise Linux 7.3 starts correctly on one machine and doesn’t start on another – the same version and installed by the same administrator.

Starting installation just complains on X Server setup:

java -jar fmw_12.
Preparing to launch the Oracle Universal Installer from /tmp/OraInstall2017-03-30_10-47-55AM
Log: /tmp/OraInstall2017-03-30_10-47-55AM/install2017-03-30_10-47-55AM.log
X-Server access is denied on host
[Fatal Error] DISPLAY variable set incorrectly: localhost:11.0
[Resolution] Verify that your DISPLAY environment variable is set correctly, 
and that there is an X11 server on the system. If you are 
running the Oracle Installer as a different user or on a different host, 
you may need to use the xhost command to ensure that host/user 
has permission to write to your display

The most interesting thing is that starting already installed GUI utils, like NETCA/DBCA/DBUA, works correctly… and they use the same X Server setup, actually through X Server Forwarding… because of this I have DISPLAY=localhost:11.0 Continue reading

Troubleshooting ‘Log File Sync’ Waits

I have been contacted by one of our customers to provide reference information on troubleshooting Oracle Log File Sync waits.

I think that this information worth short blog post.


  • Log File Sync waits occur when sessions wait for redo data to be written to disk
  • typically this is caused by slow writes(IO subsystem saturation,…)
  • spikes in Log File Parallel Write, as shown by James Morle
  • or the application is committing too frequently
  • improper Operating System configuration(check 169706.1)
  • CPU overburning(very high demand => LGWR on run queue, check Kevin Closson post)
  • high Log Parallelism, which saturates filesystem/OS, as investigated by Nikolay Savvinov
  • BUGs in Oracle(especially with RAC option) and 3rd Party software(like ODM/DISM)

Recommendations: Continue reading

Production System with Performance Problems


Recently I was involved in performance troubleshooting of one quite expensive system

that had performance problems during business hours.

I’ll not provide all details, but just post some pictures that will show resource usage:

Oracle memory allocation:

Linux memory allocation

or from other side:

cat /proc/meminfo
 MemTotal:     98848220 kB
 MemFree:      75109972 kB
 Buffers:        597460 kB

Continue reading


I have been contacted by one of our customers with quite interesting problem.

They have upgraded their oracle database to and faced really non-typical problem:

   OWN.I_TABLE_LOG_SYSTEMDAY (partition p_201202 tablespace LOG_ARCHIVE)
 , OWN.I_TABLE_LOG_ID (partition p_201202 tablespace LOG_ARCHIVE)

 DBMS_INDEX_UTL: Caused by ORA-01422: exact fetch returns more than requested number of rows
 DBMS_INDEX_UTL: Caused by ORA-01422: exact fetch returns more than requested number of rows

Customer’s DBA was able to rebuild mentioned indexes by running ALTER INDEX command provided inside error message, so why they don’t work inside ALTER TABLE … MOVE PARTITION … UPDATE INDEXES ?

There are not many references to DBMS_INDEX_UTL on My Oracle Support site and this one is definitely not among them, so I have decided that it may be a new BUG or some kind of Dictionary Corruption

Continue reading

Investigation of the 11g Oracle*Net connection delay when DNS server is unreachable

Oleksandr Denysenko:

“I’d like to introduce new Contributor to this Blog – Robert Oliynichenko.

Hi will make post on topics that are related to main direction of this Blog.

So, here we have The First Post about Slow 11.2 SQL*Net connections on AIX

Problem description:

Oracle 11g utilities like tnsping, lsnrctl or sqlplus on AIX 6.1 hanged for about 2,5 minutes (150 seconds) before connection with alias to any destination when DNS server was unreachable. In the same conditions (host and configuration) 10g utilities connected without delay. Oracle*Net was configured for local naming method only – NAMES.DIRECTORY_PATH=(tnsnames) in the both 10g and 11g Oracle Home. The tnsnames.ora files where identical in the 10g and 11g Oracle Home. The aliases in the tnsnames.ora used host names instead of IP addresses in the connection descriptions; if a host name was substituted by IP address the delay disappeared for this alias. Nevertheless all the host names from tnsnames where described in the /etc/hosts and resolution order was hosts = local, bind in the netsvc.conf (analog of  the nsswitch.conf in other UNIXs). This configuration should guarantee local name resolution when DNS server was unreachable. What is the root reason of this delay in 11g Oracle*Net ? Continue reading

Intermittent Slow Oracle Net from Windows 7/Vista/2008 machines


I have faces some interesting issue that worth a blog post.

After rebooting Windows 2003 Server with installed Oracle Database 9.2 some clients machines(with installed Windows 7) started to work very slowly with Oracle Database. Other clients, with installed Windows XP, worked as usual – fine. There no network hardware issues for Windows 7 machines – both machines were tested for the same network cable: Windows XP works fine, but Windows 7 is very slow…

Oracle sessions were tracing with 10046(level 12) event and it revealed that there are no issues with database – just network…

Listener was rebooted – didn’t helped…

System administrators noticed that Windows 2003 machine was claiming that it was not able to update root certificates, so they decided to provide Internet connection and update root certificates. Updates required server reboot and… vuala… after server rebooted everything was OK from every workstation.

Nobody was able to explain what was THE REASON, but EVERYBODY  WERE HAPPY.

Later, in two days, they required to reboot mentioned server once again, and after reboot Windows 7 workstation started working slowly…

I was there so it was time to see what is happening. Continue reading

ORA-01013 after 15 minutes in Oracle Apex through Apex Listener

Quite interesting problem was reported by our developers.

After 15 minutes of execution of long running server side procedure called from Apex(Oracle Application Experss) this call ends with:

ORA-01013: user requested cancel of current operation

According to 18604.1 ORA 1013 user requested cancel of current operation, we have next explanation:

Cause:  The user interrupted an Oracle operation by entering CTRL-C, Control-C,  or another canceling operation.
This forces the current operation to end.
This is an informational message only.
Action: Continue with the next operation.

but it’s absolutely clear that nobody has requested this cancellation (BTW – this fact has been additionally checked ;)) and what it more important – how can we “Continue with the next operation”, if previous didn’t completed successfully and it’s required for next operation ? Continue reading