What is this?

This knowledgebase contains questions and answers about PRTG Network Monitor and network monitoring in general.

Learn more

PRTG Network Monitor

Intuitive to Use. Easy to manage.
More than 500,000 users rely on Paessler PRTG every day. Find out how you can reduce cost, increase QoS and ease planning, as well.

Free Download

Top Tags

View all Tags

Oracle Tablespace sensor doesn't report correctly



So I was testing out the Oracle tablespace sensor and it created sensors for my tablespaces without any issues. The only problem I can see is the individual sensors don't seem to be reporting their values correctly. For example I have a tablespace flagged as Down - free space below the error limit of 5% so when I look at it I see these results in PRTG:

Free Blocks-396,288
Free Blocks %is empty
Free Space3096 MByte
Free Space %is empty

Using a SQL query I see these values for the same tablespace:

Total Tablespace size 3096 MBytes
Total Used space 0 Mbytes
% Used 0%

So I'm curious as to why it would report down with less than 5% remaining when in fact the tablespace is empty and has 100% remaining. In looking at the data PRTG is showing 4 tablespaces as having less than 5% remaining but those 4 are fine on space. The only common issue I see is that the 4 tablespaces are not set to autoextend but have distinctly allocated sizes. For those 4 tablespaces the Free Blocks % and Free Space % fields are empty (not calculated).

oracle oracle-tablespace-sensor prtg

Created on Dec 28, 2015 10:17:03 PM

Last change on Dec 29, 2015 12:18:40 PM by  Luciano Lingnau [Paessler]

4 Replies



Hello mcoleman,
we appreciate your contact and report.

  • Kindly confirm, which version of PRTG and which version of Oracle are you running?
  • Please add the Oracle Tablespace Sensor anew, are the results the same?

Best Regards,

Created on Dec 29, 2015 12:20:17 PM by  Luciano Lingnau [Paessler]



Sure - PRTG version Oracle version is I removed and re-added the Oracle Tablespace sensor and it had the same results. The same 4 tablespaces show as below 5% when in fact they are empty.

I also tested against a different database. All the tablespaces that had datafiles that were not set to autoextend didn't calculate free space correctly and reported down (< 5% remaining).

I selected one tablespace that with a single datafile that was set to autoextend no and was showing down in PRTG with no free space calculations. I set the datafile to autoextend yes and PRTG started calculating the free space correctly.

Created on Dec 29, 2015 2:08:01 PM



Thank you for your testing/troubleshooting.

I will forward these findings to the Sensor's developer, if we're able to resolve the issue it should be fixed in the following Stable releases of PRTG. You can keep an eye on the release notes for any updates/changes.

In the meantime if you're able to query the tablespace sizes using an SQL Expression, please use the Oracle SQL v2 Sensor to display the appropriate values within PRTG.

Best Regards,

Created on Dec 30, 2015 8:15:00 AM by  Luciano Lingnau [Paessler]



This bug is probably already fixed in the latest versions.

November 30th 2015 - Version

Bugfixes [Sensors]:


Oracle Tablespace sensor now handles auto-extensible files properly.

Created on Jan 4, 2016 11:17:03 AM by  Johannes Herrmann [Paessler Support] (1,360) 2 2

Last change on Jan 4, 2016 11:17:48 AM by  Johannes Herrmann [Paessler Support] (1,360) 2 2

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.