Before everyone diappears from The Net(tm) for Christmas: Have a nice yule-tide, don’t eat too much of the feast, don’t drink and drive, and talk the RDBMS of your choice into operating itself for at least two or three days: You won’t miss the usual 6-in-the-morning phone calls on Christmas! If you are lucky enough […]
Year: 2009
Oracle 11g: Password expired, account locked – unwanted!
Hi, it’s old news, but oracle 11g expires passwords after 180 days, and locks you out if you mistype your password 10 times, and most DBAs don’t like that. It’s unsecure, but for client-server-applications a locked account is no single-user-annoyance, it’s a downtime killing SLAs, nerves and – hopefully not – DBA jobs. So just […]
DOAG Konferenz 2009: Impressions Day 3 (final)
Thursday 19th was the last day of DOAG Confernce 2009. Compared with the second day, the program was much more dense: For my (DBA) profile there have been several hours, where more that one talk would have been appropriate. This list is, what I collected during the day. […]
DOAG Konferenz 2009: Impressions Day 2
As promised, today my impressions of yesterday (confusing, I know). Clarification: This is about Wednesday, November 18th. I’m still at DOAG Conference 2009 in Nuremberg. Wednesday was a silent day for my interests, especially at noon there have been less talks being of interest, but maybe they have done something for my general knowledge… So […]
DOAG Konferenz 2009: Impressions Day 1
These days, the DOAG Conference 2009 happens in Nuremberg, Germany. First day was yesterday, Tuesday November 11th 2009. This is a machine-readable copy of my scratchpad, coming from the different talks I attended. Sun Oracle Database Machine Exadata 2: The “Quarter Rack” (consisting of 2 Servers and 3 storage nodes) sounds interesting. 11gR2 has some […]
New My Oracle Support (ex. Metalink): Use without flash: HTML Option
In the last days, My Oracle Support was redesigned. But since flash is a performance eater and not always available, people like to have an option to use My Oracle Support (formerly Metalink) with HTML only. The link to it is well-hidden, but nevertheless useful! Give it a try: https://supporthtml.oracle.com Best regards Usn […]
Oracle: Recreate PLAN_TABLE
drop table plan_table; @?/rdbms/admin/utlxplan.sql […]
AIX: Avoiding “ORA-27126: unable to lock shared memory segment in core”
Did you ever change lock_sga = true for an Oracle Instance on AIX 5.3, and did see ORA-27126: unable to lock shared memory segment in core IBM AIX RISC System/6000 Error: 1: Not owner in Return? Do the following: # vmo -o v_pinshm v_pinshm = 0 # vmo -o v_pinshm=1 Setting v_pinshm to 1 # […]
Oracle 11gR2 ASM / ACFS: A first benchmark (poorly)
Hi folks, since Oracle 11g Release 2 is out now, I had to test one of the most-missed ASM features: the ASM cluster file system ACFS. My Setup: Two VMware nodes with 2 CPUs and 1,5GB of RAM each Oracle Enterprise Linux 5.3 x86_64 Four virtual cluster disks from the ESX server, 10GB in size […]
Oracle 11gR2 ASM: Changed permission policy (ORA-15260)
Did you recently see the new error ‘ORA-15260: permission denied on ASM disk group’ in your ASM administration? Maybe you are still connected as SYSDBA, old habit from 10g? A quick citation from the Oracle Docs: The SYSOPER privilege permits the following subset of the ALTER DISKGROUP operations: diskgroup_availability, rebalance_diskgroup_clause, check_diskgroup_clause (without the REPAIR option). […]
Oracle 11g Release 2 documentation
The long-awaited 11gR2 is out, at least for Linux x86 and x86_64 now. Marketing will show you all the features, but the most important link is to the documentations: http://www.oracle.com/pls/db112/homepage Use it well! Usn […]
Oracle: Executing an OS command from PL/SQL – ICMP ping from database
Executing OS commands from SQL or PL/SQL is easy as long as you are in SQL*PLUS – just do a host command. But I must confess, that this is a really useless hint. 🙂 Much more interesting is to execute an OS command with a DBMS_SCHEDULER job, but this is not possible in every case, […]
Oracle: Tracing of another session
I simply love 10046 level 12 traces. I described session tracing based on a logon trigger quite earlier, but some situations in real DBA life need this trace event switched on for a session other than my own AND for a short peroid in time (with no need for the connected user to log out). […]
Oracle: Audit a failed logon attempt without auditing
Oracle has a disadvantage: It allows no trigger BEFORE LOGON ON DTATBASE! 🙂 For obvious reasons, this would be nonsense, but there’s a need for it! Auditing failed logon attempts, for example. Of course, there’s Oracle Auditing. But IMO, setting up an audit trail for one Email in one case looked like the overkill to […]
String concat with hierarchical query and sys_connect_by_path(): Avoid ORA-30004
In the last days, I touched hierarchical queries – it’s a strange field for a DBA, but I did need it for DBA desires: A sophisticated query on statspack. Why? Since oddly, the stats$sql_text table of statspack / perfstat DOES contain the full SQL for a statement, but fragmented over various lines. But I had […]
Oracle IMPDP: Wildcard hacking
Sometimes you want to use datapump import (impdp) for smart problems. An example is excluding (or including) a subset of objects, like tables. The usual way to do so is the EXCLUDE keyword. (Footnote: All examples in this post are written for a parameter file, so don’t forget a proper quoting for your shell if […]
Oracle: Query/Monitoring autoextend of datafiles
Did you ever wonder how to see whether your datafile is on autoextend or not, or monitor the autoextension to keep eyeballs on target? The Oracle EM is a simple tool for that, but some people do prefer the direct query. See a little example to query or autoextend a datafile. select * from dba_data_files […]
Oracle: Change (default) TEMP and UNDO tablespace to bigfile tablespaces
That’s how to change the Oracle Database’s TEMP and UNDO tablespaces to bigfile (as possible in 10g and above). It’s something I usually do for every DB I install. create bigfile temporary tablespace TEMP1 tempfile \ size 10G autoextend on next 1G maxsize 20G; create bigfile undo tablespace UNDO1 datafile \ size 10G autoextend on […]
Oracle 11g look-at’s
That’s a personal, quite unsorted list of (new or older) features I recently collected. All of them are things, I’d consider valuable or at least important to care about as soon as 11g is involved. It might be for system architecture knowledge, concept tasks, DBA hands-on, good-to-know or any other thing that my happen in […]
Oracle: Convert a partitioned table into an unpartitioned one
License fees can bee massive. So for some machines it’s just useless to buy Oracle Enterprise Edition, sometimes Standard Edition is simply enough. Migration to SE for a schema with partitioned tables leaves you one option: CTAS all partitioned tables and export them, reimport them on your new box and modify all DBMS_METADATA-generated DDLs so […]
Talk: IT Performance
On Thuesday, March 24th, 2009 at 9 a.m. I will speak at Berufsschule Wiesau about general matters of IT performance. Papers and the presentation are available online now: Handout “IT-performance” Slides Regards Martin Klier EDIT: That’s a nice article about the event on the school’s webpage. Thanks! […]
Oracle: Specify the number of occurrences before metric alerting starts
It’s not possible to specify a minimum of consecutive occurrences before alerting starts in in Enterprise Manager, it will always scream out at first time touching the line. But you can do so in command line. Just execute DBMS_SERVER_ALERT.SET_THRESHOLD with parameter consecutive_occurrences set to a value >1. It’s a very nice way to stop annoying […]
Oracle Explain Plans or Execution Plans: Guess or Reality?
Oracle finally desupported the rule-based optimizer with version 10g. Since 9i, users are good adviced to make themself familiar with the cost-based-optimizer (CBO). In order to understand what happens with your statement after parsing with CBO involved, and to be able to tune your queries, displaying, understanding and optimizing explain- or execution plans is essential. […]
Get Oracle User DDL with dbms_metadata
Sometimes you have to recreate a user in a DB, and you like it to be the same as before again. To have its DDL at hand is usually rather convenient. DBMS_METADATA is a great toolbox to get it, my example is just a short but hopefully useful excerpt of its possibilities: set long 200000 […]
Oracle 11g JDBC driver hangs blocked by /dev/random – entropy pool empty
On a headless (=without console) network server, the 11g JDBC driver used for (java) application connect may cause trouble. In my case, it refused to connect to the DB without any error, trace or log entry. It simply hung. After several hours, it connected one time, and freezed again. Remote debugging done by the development […]
Creating Oracle AWR reports quicksheet
For comparing, classifying, benchmarking and forecasting databases, Oracle’s Automatic Workload Repository (AWR) is neat. (But remember! You will need a diagnostics pack license for that as described here and here – if you need a free technology for performance monitoring, consider using Craig Shallahamer’s OSM toolkit.) This post simply describes the package calls to create […]
Setting ulimit -m in AIX
AIX has its own rules, as I have to discover these days. Coming across ulimit, I found out that smitty configures value A here and value B completely elsewhere. Hardest one so far has been “ulimit -m” (“Specifies the size of physical memory, in number of K bytes.” a user can assign), since I could […]
“Basics of Database Technology” again
Tomorrow, there will be a version 2.0 of a lecture from last year, again for 9th-formers of Augustinus Weiden. The handout and the presentation are online now, we will see what Friday brings. Usn […]