Oleksandr Denysenko's Blog


Global Context + Session Client Identifier = Strange Behaviour or Documentation BUG ?

Filed under: BUG,oracle — odenysenko @ 16:11
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Here I’ll describe some strange/interesting/ behaviour of Global Application Context connected with usage of Session Client Identifier, that is quite usually met in Application Express, J2EE Agent, Oracle Data Integrator starting from release and many other applications that uses JDBC Connection Pooling in conjunction with setting Session Client Identifier.

So what is the problem ?

The problem is that Global Application Context doesn’t work as expected and described in documentation – attributes’ VALUES ARE NOT VISIBLE(more…)


Oracle Database Patchset is ready for downloading

Filed under: 11.2,,oracle — odenysenko @ 11:12
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Oracle RDBMS PatchSet version is available for downloading since 27-AUG-2013 ! again some time earlier than OOW2013

But(as of 29-AUG-2013) it’s still available only for Linux x86-64 + Linux x86 and all Oracle Solarises(x86, x86-64, SPARC 32-bit, SPARC 64-bit)

Checked on 29-OCT-2013 – patchset aditionally available for next platforms: Microsoft Windows(32-bit), Microsoft Windows x64(64-bit), HP-UX Itanium(32-bit), HP-UX Itanium(64-bit), IBM AIX on POWER Systems (32-bit), IBM AIX on POWER Systems (64-bit)

Based on  NOTE:742060.1 Release Schedule of Current Database Releases:

  • on Linux x66(new platform ? ;)) released – this joke no more present in mentioned document😉
  • this is the terminal patch set for 11.2 (more…)


Funny Package Non-Compilation Issue

Filed under: BUG,oracle — odenysenko @ 17:50
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Today I was contacted by one of our customers with very non-typical issue on their database. They have added new column to one table at the middle of the day and now they are not able to compile some of invalidated packages.

Now I’m clarifying what does it mean ‘NOT ABLE TO COMPILE‘:

Package altered.

No errors.

Package body altered.

No errors.

select object_type,status from dba_objects where object_name='PKG_ERP_MAIN';
------------------- -------
PACKAGE             VALID

Funny! Isn’t ? (more…)


Funny FBDA BUG: ORA-00600 [ktfa_error_handler_map], [942]

Filed under: 11.2,BUG,FBDA,oracle — odenysenko @ 16:49
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I have faced quite interesting situation with Flashback Data Archive(FBDA)  that wasn’t covered yet in blogosphere.

So I have just created new Flashback Archive and altered some tables specifying it(Flashback Archive).

Just after some time of any DMLs on altered tables next error appears in alert.log

Starting background process FBDA
Thu Feb 21 11:07:07 2013
FBDA started with pid=203, OS id=3626
Errors in file /u01/app/oracle/diag/rdbms/siam_opt/siamopt/trace/orcl_fbda_3626.trc  (incident=57628):
ORA-00600: internal error code, arguments: [ktfa_error_handler_map], [942], []
ORA-00942: table or view does not exist

Please, notice presence of additional funny error  – ORA-00942. Why it may be here ? we’ll see later… (more…)


Oracle 12cR1 Upgrade Companion – Coming Soon [ID 1462240.1]

Filed under: 12.1,12c,oracle — odenysenko @ 19:25
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Just short post about Something Coming Soon from mentioned note

Modified:Jan 23, 2013

COMING SOON!!! Stay Tuned


Still have to wait😉


No Oracle Database 12c(12.1) was released on 12.12.(20)12…

Filed under: 12.1,12c,oracle — odenysenko @ 12:07
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Despite the fact that there were some speculations that Oracle Database 12c will be released on 12.12.(20)12 to use the Magic of 3×12, this opportunity was missed by Oracle and Release 12c is still in Beta Testing period,

so we have to wait for the another ‘good’ moment like 3×13(12.13.[20]13) 😉

Later we’ll see if it add more power to new Release…😉


Troubleshooting ‘Log File Sync’ Waits

Filed under: oracle,performance,Troubleshooting — odenysenko @ 17:30
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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: (more…)


Production System with Performance Problems

Filed under: oracle,performance,Troubleshooting — odenysenko @ 00:06
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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


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