Shoring up SQL Skills

Goal for 2014:  Revisit weak points in my knowledge of SQL.  Going to try http://www.sql-ex.ru/ to help improve those skills.  I'll report back on how it goes.

Unable to register database with DBCA

Attempting to register a database with DBCA and got the following error message:

TNS-04409: Directory service error caused by: oracle.net.config.DirectoryServiceException: TNS-04405: General error caused by: oracle.net.ldap.NNFLException

Thought thought perhaps the problem was something like this issue with password policys, but it turns out it was simply that I needed to change how anonymous binds are handled. Per Doc ID 947285.1, check the value of orclanonymousbindsflag. I had it set to "2", which didn't work. Setting it to "1" allowed me to register the database, and then I set it back to 2 as it is a more secure setting.

RMAN cannot restore from backupset copied to disk from tape

Attempting to work around an issue with our backup system, I copied the backup pieces from a known-good backup from tape to disk. Then I attempted to catalog those pieces for a recovery attempt. Cataloging those pieces failed.

RMAN> catalog backuppiece '/u01/app/oracle/admin/scripts/restore/filetest/DB_3rn2tp0j_1_1';

using target database control file instead of recovery catalog
ORA-19870: error while restoring backup piece /u01/app/oracle/admin/scripts/restore/filetest/DB_3rn2tp0j_1_1
ORA-19587: error occurred reading 0 bytes at block number 1
ORA-27067: size of I/O buffer is invalid
Additional information: 2

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of catalog command at 02/17/2012 09:37:20
RMAN-06209: List of failed objects
RMAN-06211: ==========================
RMAN-06212:   Object Type   Filename/Handle
RMAN-06213: --------------- ---------------------------------------------------
RMAN-06214: Backup Piece    /u01/app/oracle/admin/scripts/restore/filetest/DB_3rn2tp0j_1_1

Eventually found Oracle Support Doc ID 1111603.1 on the subject. Essentially, no, you can't catalog a backup piece that's been restored from tape to disk because the header information will be different than the file at rest on tape.

A bad use of find in a nightly script

I was going through cleaning up files on one of the database servers. I happened to find this script.

> cat /home/oracle/scripts/rm_old_alogstrc.shl
cd /u03/oradata/SID/archivelog
find . -mtime +2 -exec rm {} \; 
cd /u01/app/oracle/admin/SID/adump
find . -mtime +7 -exec rm {} \;
cd /u01/app/oracle/admin/SID/bdump
find . -mtime +7 -exec rm {} \;
cd /u01/app/oracle/admin/SID/cdump
find . -mtime +7 -exec rm {} \;
cd /u01/app/oracle/admin/SID/udump
find . -mtime +7 -exec rm {} \;
cd /home/oracle/datapump/SID
find . -mtime +7 -exec rm {} \;
cd /home/oracle/exports/SID
find . -mtime +7 -exec rm {} \;

For the benefit of those not cringing as you read that. Two major things I see wrong with it. The first is that someone had entrusted the OS to clean up old archivelog files older than 2 days. While it's not so common with all the safeguards we put in place for backups, but I can still imagine scenarios where archivelogs don't get backed up off the server in 2 days. This script runs and poof there goes recoverability.

And the second which makes me cringe is the two step file removal. Specifically cd to some directory and then rm all files in that directory. Just imagine what would happen if that script didn't change directory. Next you know whatever the working directory was is effectively wiped out. It was likely the home directory.

The much better way is to combine it into one command, that way there's no accidental deletions.

find /home/oracle/exports/SID -mtime +7 -exec rm {} \;

In a way I wish I didn't see this. Now I wonder what other gems are out there on this server that someone left me.

Manually remove oracle server software on Microsoft Windows Platforms

What happens if Oracle deinstall.bat doesn't cleanly remove all the windows components? Try using doc id 1069034.1: 11.2: How to Manually Remove Oracle Server Software on Microsoft Windows Platforms [ID 1069034.1]

Nice try

Tired of looking this up... so I'm posting it. I don't use the unix nice command very often, but when I do, the man page seems a little confusing. Here's the format I typically use the command:

nice -n +19

That runs the command at the lowest possible priority, helpful if you're going to do some big file op and don't want to cause anyone else any grief.

What service has oci.dll open?

Attempting to use deployment procedure's to install patch bundles on windows hosts, sometimes you run into issues with services keeping dll's (especially oci.dll) open.

Here's a trick to determining what service is keeping a specific dll open.

From a command prompt:

tasklist /m > tasks.txt 

notepad tasks.txt 

The look for the specified dll in tasks.txt and find the process. From there it should be somewhat obvious which service to shut down in order to get the patch to continue.