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Oracle memory troubleshooting using analysis on heapdumps, part 2

In the article oracle memory troubleshooting using analysis on heap dumps I introduced heap_analyze.awk.

The reason the tool exists is because I am using it myself. Therefore, I ran into additional things that I wanted the tool to do. I added some stuff, which is that significant, that I decided to make another blogpost to introduce the new features.

1. Percentages
In order to get an idea of the relative size of the summarised topic, I added a percentage. For example:

Oracle memory troubleshooting using analysis on heapdumps

This blogpost is about analysing Oracle heap dumps. It is an extension to earlier work, Tanel Poder’s heap dump analyzer. So hat tip to Tanel, he’s done the hard work, I merely increased the presentation options. The heap analyser script that I wrote analyses Oracle heapdumps from the trace file that the dump was written to by the Oracle database. Because the heap dump representation is the same between PGA and SGA memory, it can work on both. The reason for this is that memory management is done by the same memory manager, and is commonly called ‘kgh’ (kernel generic heap) managed memory.

Please mind that for PGA analysis, not all memory is managed by the kgh memory manager. For example memory used for networking (sqlnet) is allocated totally outside of the kgh memory manager.

What’s new with Oracle database 19.4 versus 19.3

The most notable thing here is an “official” (non-underscore) parameter has been introduced with 19.4, “ignore_session_set_param_errors”. The description is: ‘Ignore errors during alter session param set’. I did a quick check to see if I could set it to true or false, which I couldn’t (resulted in an error).

With the Oracle database version 19.3 patched to 19.4 on linux, the following things have changed:

What’s new with Oracle database 18.7 versus 18.6

With the Oracle database version 18.6 patched to 18.7 on linux, the following things have changed:

What’s new with Oracle database 12.2.0.1.190416 versus 12.2.0.1.190716

There are a couple of underscore parameters changed from spare to named ones.
It’s interesting to see that in sysstat, ‘spare statistic 2’ changed to ‘cell XT granule IO bytes saved by HDFS tbs extent map scan’. This obviously has to do with big data access via cell servers. What is weird is that this is the only version where this had happened.

What’s new with Oracle database 12.1.0.2.190416 versus 12.1.0.2.190716

There are a couple of undocumented spare parameters changed to named undocumented parameters, this is quite normal to see.

With the Oracle database version 12.1.0.2.190416 patched to 12.1.0.2.190716 on linux, the following things have changed:

Getting locale warnings when logging on to Linux

This blogpost is about the reason and solving getting the following message, or messages alike these when logging i to a linux box using ssh:

-bash: warning: setlocale: LC_CTYPE: cannot change locale (UTF-8): No such file or directory

However, this is a warning. Please mind such an issue might be come up in another way, which can be more disrupting; at least in the past I had issues running perl for the same issue:

[root@dmcel01 ~]# /usr/local/bin/ipconf -verify
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LANGUAGE = "en_US.UTF-8",
LC_ALL = "UTF-8",
LC_CTYPE = "UTF-8",
LANG = "en_US.UTF-8"
are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").

OBUG Tech Days Belgium 2019 – Antwerp – 7/8-FEB-2019

Agenda: https://www.techdaysbelgium.be/?page_id=507

Dates: February 7 and 8, 2019

Location: http://cinemacartoons.be in Antwerp, Belgium

More information soon.

For people from the netherlands: this is easy reachable by car or by train! This is a chance to attend a conference and meet up with a lot of well-known speakers in the Oracle database area without too extensive travelling.

opatch investigations

This blogpost is about opatch and how to obtain information about the current oracle home(s), and how to obtain information about the patches to be applied.

Patches that can be applied using opatch are provided by oracle as zip files which have the following naming convention:
p[patchnumber]_[baseversion]_[platform]-[architecture].zip. The patch normally contains an XML file called ‘PatchSearch.xml’ and a directory with the patch number. Inside the patch number directory there is a README.txt which is lame, because it says ‘Refer to README.html’, and a README.html that contains the readme information that is also visible when the [README] button for this patch is selected in MOS.