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Bugs with rm -rf from within asmcmd

Performing an rm -rf operation is normally a simple operation albeit risky if you are in the wrong folder. However within ASMCMD there are a couple of bugs associated with it.

Here are two examples and workrounds

Converting an SCN to a timestamp

Something nice and simple

It is easy to get the current SCN from the database and to map between SCN and timestamp because from 10g onwards there are 2 functions to convert between SCN and TIMESTAMP

Another really enjoyable UKOUG Database SIG

Today’s venue was the Metropole Hotel in the centre of Leeds and there was a good attendance, encouraged by a strong agenda.

After introductions, health and safety and UKOUG information it was straight into techie talk with Phil Davies from Oracle doing his normal support update (although he does share duties with Owen Ireland). Invariably I make more notes from this session than most others I hear because of the wealth of information it contains. Snippets I jotted down that are worthy of sharing are :-

In praise of bloggers (along with sql_profiles and RAC interconnect pings)

Today I am going to mention two articles which I came across in the last few days whilst investigating problems and talk about the background to the problems but also praise the articles. I am sure many of us have run the SQL Tuning advisor from within OEM or using the DBMS_SQLTUNE package from the command line and often it recommends a sql_profile that should be applied, (invariably giving 99.98 perceived benefits). Now I see this as both a good thing and a bad thing.

Don’t forget the emctl reload agent command

Just a quick entry to show the use of a command that I had forgotten existed but it seemed to work nicely

Problem  – OEM12C agent had been down for a few days on a non-production server and more than the maximum number of files had been created ready to be uploaded.

emctl status agent

aud$ and ASSM – a good combination

We had a 8 node RAC cluster that was showing evidence of connections timing out. The following AWR report segments indicates a high level of login activity and blocking on the AUD$ table and segments.

ex3

The ‘rfs writes’ event on a DataGuard standby database

It is well known that poor performance on the standby server of a DataGuard pair can affect the performance of the primary database. This post shows an example and how to use the view GV$EVENT_HISTOGRAM to track down an issue.

The databases were 11.2.0.1 on HPUX. I had been seeing alerts from OEM to state that the standby was seeing lag_apply delays when applying redo to standby. Looking at the primary database alert log I could see the entries

Serious BUG alert – RMAN Duplicate overwrites datafiles at original location

Please be aware of the serious bug identified with RMAN duplicate database on the same node with versions 11.2.0.2 and 11.2.0.4

Bug 13498382  ORA-1122 ORA-1208 RMAN Duplicate overwrites datafiles at original location despite db_create_file_dest

This note gives a brief overview of bug 13498382.
The content was last updated on: 07-FEB-2014
Click here for details of each of the sections below.

Invisible Indexes – a real world example and a bit of LogMiner

We had a requirement to perform a one-off update on a table of around 1.2M rows. There were 11K statements similar to the one below, with varying values and predicates updating a variety of rows from 20 to 500. The potential elapsed time was around 44 hours due to the volume of full table scans involved.

The obvious thing to do was to create an index but this was production and it was urgent so no time to go through the full route to live test cycle.

Oracle Restart – going , going , gone?

Oracle restart is an 11GR2 feature which ensures that all services on a standalone installation start up in the correct order. As such it seems to work well. One bugbear I have with it is that it changes the order of entries in the /etc/oratab file. Personally I like my oratab to be ordered in terms of database (most used first), ASM, then agents. In that way when I logon to a box and it automatically sets the SID it picks up the first entry which is commonly the database I want to work with.

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