I’ve been breaking my head over a problem I had with the UTL_FILE.FREMOVE command trying to remove a file created by another (not oracle) process. On *nix command line, logged in as user oracle (same as database) I’m able to remove the file using the “rm” command, but when using UTL_FILE.FREMOVE it comes back with ORA-29283. Sample of directory and… Read more »
RECOMMENDATION: Set the deferred_segment_creation parameter to FALSE for 11.2 RAC databases! Recently our monitoring picked up an ORA-600 from the alertlog of one of our 11.2 RAC instances. ORA-00600: internal error code, arguments: [kkpo_rcinfo_defstg:objnotfound],[87421], [], [], [], [], [], [], [], [], [], [] Oracle Support was telling me that I was hitting bug 14252187 (Bug 14252187 – ORA-600 [qesmaGetTblSeg1]… Read more »
In our cloning procedures we use the RMAN “DUPLICATE” command for duplicating databases. This all went fine for a long time until one moment we start getting errors during the duplication process (from the point where media recovery gets started). Here is an example of the errors we received: RMAN-00571: =========================================================== RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS =============== RMAN-00571: ===========================================================… Read more »
Last week I was trying to find a way to determine the version of the Oracle clients that are connected/connecting to databases from these databases. We cannot connect to each application server to figure out the used version and certainly not all laptops and desktops from which some users can connect. The v$session_connect_info view contains a column named client_version so… Read more »
Recently a security researcher (Esteban Martinez Fayo) made the world aware of a problem with the O5LOGON Oracle database authentication protocol (used in 11g – 11.1 & 11.2). This problem, known as CVE-2012-3137, makes it relatively simple for attackers to get hold of passwords using a brute-force attack on the encrypted (AES -192 bit) session key that is returned by… Read more »
Warning: I use the Oracle Block Browser and Edit tool (bbed) for studying the internal structure of database blocks. Be very careful using the tool, you can destroy blocks using this tool so make sure you know what you are doing. There is a nice document (PDF) about the BBED tool, titled Disassembling the Oracle Data Block which can be… Read more »
A snapshot controlfile is a read consistent copy of a database controlfile which RMAN creates because the controlfile is changed constantly. As of Oracle 11.2 (11.2.0.2 to more precise) the snapshot controlfile must be on a location shared by all RAC nodes in a cluster (it must be accessable by all nodes on which instances for an RAC database can… Read more »
This post will show you the order in which SQL*Plus for Solaris reads the configuration files like the tnsnames.ora. tnsnames.ora $HOME/.tnsnames.ora $TNS_ADMIN/tnsnames.ora /var/opt/oracle/tnsnames.ora $ORACLE_HOME/network/admin/tnsnames.ora If the specified alias is not found in (or the file does not exists) in $HOME/.tnsnames.ora it will try to find the alias in the next available file using the above order. If such a file… Read more »
We had a situation where we had to set the sqlnet.expire_time parameter in the sqlnet.ora file to avoid firewall dropping “inactive” sessions. The only problem was that we were not allowed to restart the listener or the database instance. Searching through the Oracle documentation and google just didn’t give a solid answer what needs to be restarted to start using… Read more »
In the last couple of months we had some strange problems with all processes of Oracle database and ASM instances just disappearing. The shared memory segment was still there and you could connect internally to the instance, even execute some queries until you give some statement where it actually needed to do something, resulting in some kind of a “ghost”… Read more »