Mass datafile resizing

Recently I needed to extend many datafiles on a database with more than 500 tablespaces because a lot of tablespaces were reaching the critical threshold.
Autoextend was not an option due to a bug I encountered on 10gR2 RAC on ASM and AIX.

The solution was the following script: it generates statements to autoextend datafiles with usage over a defined threshold (the “80” in the where clause) to low down the percentage below another defined threshold (the “75” in the select clause).

Prior to extend it’s possible to show how much space is required to do this mass resizing:

Dog eat Dog… Oracle deletes itself by mistake!

While implementing the backup on a new DB inherited from a customer, I scheduled our standard backup “type disk” procedure through rman, on Windows.
The morning after I saw that the “delete obsolete” tried to delete ALL CURRENT DATAFILES!!

i criteri di conservazione RMAN verranno applicati al comando
i criteri di conservazione RMAN sono impostati su una ridondanza 1
canale allocato: ORA_DISK_1
canale ORA_DISK_1: sid=29 devtype=DISK
Eliminazione dei seguenti backup e copie obsoleti:
Tipo Chiave Ora fine Nome file/Handle
-------------------- ------ ------------------ --------------------
Set di backup 917 28-GIU-11
...
Set di backup 927 29-GIU-11
Backup piece 1005 29-GIU-11 H:\ORACLE\BACKUP\ORAPERSP\RMAN\SPFILEBCK_20110629
Copia file di dati 14 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\INDX01.DBF
Copia file di dati 16 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\TOOLS01.DBF
Copia file di dati 17 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\USERS01.DBF
Copia file di dati 18 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\DRSYS01.DBF
Copia file di dati 19 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\EXAMPLE01.DBF
Copia file di dati 20 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\ODM01.DBF
Copia file di dati 21 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\XDB01.DBF
Copia file di dati 22 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\CWMLITE01.DBF
Copia file di dati 23 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\TBLDATI01.ORA
Copia file di dati 24 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\TBLINDEX01.ORA
Copia file di dati 25 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\OEM_REPOSITORY1.ORA
Copia file di dati 26 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\SYSTEM01.DBF
Copia file di dati 27 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\UNDOTBS01.DBF
backup piece eliminata
...
backup piece eliminata
handle di backup piece=H:\ORACLE\BACKUP\ORAPERSP\RMAN\C-2220366420-20110628-02 recid=990 stamp=755031582
backup piece eliminata
handle di backup piece=H:\ORACLE\BACKUP\ORAPERSP\RMAN\C-2220366420-20110629-00 recid=1002 stamp=755130872
backup piece eliminata
handle di backup piece=H:\ORACLE\BACKUP\ORAPERSP\RMAN\CTL_20110629 recid=1004 stamp=755130883
backup piece eliminata
handle di backup piece=H:\ORACLE\BACKUP\ORAPERSP\RMAN\SPFILEBCK_20110629 recid=1005 stamp=755130885
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of delete command on ORA_DISK_1 channel at 06/29/2011 22:34:55
ORA-19584: file E:\ORACLE\ORADATA\ORAPERSP\INDX01.DBF già in usoRecovery Manager ha terminato.

That’s because all current datafiles were registered into recovery catalog as backup copy. With a recovery redundancy of 1, all datafiles were set as obsolete! But since it’s windows, a delete command doesn’t delete datafiles if they are already in use. What it was on unix? We had just luck!

Then we had to uncatalog all copies.


RMAN> list copy;

la specifica non corrisponde a nessuno dei log di archivio del Recovery Catalog

Lista di copie del file di dati
Chiave SCN Ckp file S Ora di completamento Nome Ora ckp
------- ---- - -------------------- ---------- -------------------- ----
26 1 X 29-NOV-10 18535127593 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\SYSTEM01.DBF
27 2 X 29-NOV-10 18535127762 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\UNDOTBS01.DBF
14 3 X 29-NOV-10 18535122625 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\INDX01.DBF
16 4 X 29-NOV-10 18535123721 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\TOOLS01.DBF
17 5 X 29-NOV-10 18535124423 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\USERS01.DBF
18 6 X 29-NOV-10 18535124439 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\DRSYS01.DBF
19 7 X 29-NOV-10 18535124453 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\EXAMPLE01.DBF
20 8 X 29-NOV-10 18535124554 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\ODM01.DBF
21 9 X 29-NOV-10 18535125790 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\XDB01.DBF
22 10 X 29-NOV-10 18535125874 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\CWMLITE01.DBF
23 11 X 29-NOV-10 18535125887 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\TBLDATI01.ORA
24 12 X 29-NOV-10 18535126750 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\TBLINDEX01.ORA
25 13 X 29-NOV-10 18535127211 29-NOV-10 E:\ORACLE\ORADATA\ORAPERSP\OEM_REPOSITORY1.ORA


RMAN> change copy of datafile 1..N uncatalog;

copia non catalogata del file di dati
filename di copia del file di dati=E:\ORACLE\ORADATA\ORAPERSP\INDX01.DBF recid=14 stamp=736336991
Oggetti 1 non catalogati
...

until no “obsolete” current datafile were reported!


RMAN> report obsolete;

i criteri di conservazione RMAN verranno applicati al comando
i criteri di conservazione RMAN sono impostati su una ridondanza 1
non sono stati trovati backup obsoleti

Lesson learned: never schedule delete obsolete without actually checking what could be deleted!

10gR2 RAC hangs and “KSV master wait”

We recently migrated a customer’s 10gR2 RAC on AIX6.1 from GPFS+HACMP to a “basic” Clusterware with datafiles over ASM.
After (many) problems related to various installation bugs (the list of requirements for AIX is very long, incomplete and requires many one-off patches to complete), we had a problem during an import of a new schema: the import hung with no apparent wait events. We found that the event it was waiting for was classified as ‘Idle’:

The on ASM instance:

The problem was related to datafile resize (we use autoextend) and according to MOS, we were encountering a bug:

Bug 11712836: RESIZING DATAFILE HUNG WAITING FOR KSV MASTER WAIT IN RAC

Shutting down one instance solved the problem. Now we have to avoid autoextend……. We never encountered this bug in many 10.2.0.4 rac installations.

Dataguard check script for Real Application Clusters (MAA)

Two years after my posts:
Quick Oracle Dataguard check script and More about Dataguard and how to check it I faced a whole new Dataguard between two Oracle Real Application Clusters, aka Oracle Maximum Availability Architecture (MAA).

This enviromnent is relying on Windows OS. Don’t know how this could be called “availability” but here we are. I revisited my scripts in a quick and very dirty way. Please consider that I did copy and paste to check the alignment once per thread, but it should be improved with some kind of iteration to check each thread in a more structured fashion.

Please foreward me every improvement you implement over my code: it would be nice to post it here.

Oracle capacity planning with RRDTOOL

RRDize everything, chapter 2

Oracle Database Server has the most powerful system catalog that allows to query almost any aspect inside an oracle instance.
You can query many v$ fixed views at regular intervals and populate many RRD files through rrdtool: space usage, wait events. system statistics and so on…

Since release 10.1 Oracle has introduced Automatic Workload Repository, a finer version of old good Statspack.
No matter if you are using AWR or statspack, you can rely on their views to collect data for your RRDs.

If you are administering a new instance and you haven’t collected its statistics so far, you can query (as example) the DBA_HIST_BG_EVENT_SUMMARY view to gather all AWR data about wait events. Historical views could be useful also to collect historical data once a week rather than query the fixed views every few minutes doing the hard work twice (you and AWR).

The whole process of gathering performance data and update rrd files can be resumed into the following steps:

– connect to the database
– query the AWR’s views
– build and execute an rrdtool update command
– check if rrd file exists or create it
– update the rrd file

The less rrdtool update commands you will execute, the better the whole process will perform.
Do it in a language you are comfortable with and that supports easily connection descriptors.

Since I’m very comfortable with php, I did it this way.

This is a very basilar script that works greatly for me with good performances:

Depending on how many different wait events you have, you’ll have a certain number of rrd files:

As you can see, they are not so big…

Once you have your data in rrd files, it’s quite simple to script even complex plots with several datasources. Everything depends on the results you want.
This script stack all my wait events for a certain instance: it takes the directory containing all the rrds as first argument and the number of hours we want to be plotted as second argument:

The resulting command is very long:

This is the resulting graph:
Graph plotted with rrdtool displaying Oracle instance Wait Events

OHHHHHHHHHHHH COOOOL!!!
😉

Any comment is appreciated! thanks

How to collect Oracle Application Server performance data with DMS and RRDtool

RRDize everything, chapter 1

If you are managing some Application Server deployments you should have wondered how to check and collect performance data.
As stated in documentation, you can gather performance metrics with the dmstool utility.
AFAIK, this can be done from 9.0.2 release upwards, but i’m concerned DMS will not work on Weblogic.

Mainly, you should have an external server that acts as collector (it could be a server in the Oracle AS farm as well): copy the dms.jar library from an Oracle AS installation to your collector and use it as you would use dmstool:

There are three basilar methods to get data:

Get all metrics at once:

Get only the interesting metrics:

Get metrics included into specific DMS tables:

What youraddress:// is, it depends on the component you are trying to connect:

If you are trying to connect to the OHS (Apache), be careful to allow remote access from the collector by editing the dms.conf file.

Now that you can query dms data, you should store it somewhere.
Personally, I did a first attempt with dmstool -dump format=xml. I wrote a parser in PHP with SimpleXML extension and I did a lot of inserts into a MySQL database. After a few months the whole data collected from tens of servers was too much to be mantained…
To avoid the maintenance of a DWH-grade database I investigated and found RRDTool. Now I’m asking how could I live without it!

I then wrote a parser in awk that parse the output of the dms.jar call and invoke an rrdtool update command.
I always use dms.jar -table command. The output has always the same format:

So I written an awk file that works for me.
use it this way:

And this is the code for update_metric_rrd:

Once you have all your rrd files populated, it’s easy to script automatic reporting. You would probably want a graph with the request count served by your Apache cluster, along with its linear regression:

This is the result:
OHS request completed
OHHHHHHHHHHHH!!!! COOL!!!!

That’s all for DMS capacity planning. Stay tuned, more about rrdtool is coming!

More about Dataguard and how to check it

After my post Quick Oracle Dataguard check script I have some considerations to add:
to check the gap of applied log stream by MRP0 process it’s sufficient to replace this query in the perl script I posted:

with this new one:

To check this you have to meet the following condition: You should have real-time apply enabled (and possibly NODELAY clause specified in your recover statement). Check it with this query:

It should be “MANAGED REAL TIME APPLY”.
If not using realtime apply your MRP0 process will wait until you have a new archive, so even if you have redo transport mode set to LGWR you’ll wait for standby log completion. Your gap of applied redo stream will be at least one sequence#.

With transport mode set to LGWR and real-time apply the output of the perl script is similar to this one:

The whole gap between your primary and standby database should be LOW.

Clustering the RMAN catalog on a RAC environment

You have your brand new RAC deployed on a cluster and you want to manage your backups through a recovery catalog.
Suppose you don’t have a dedicate server to host your catalog, perhaps you wouldn’t configure your catalog as a RAC database: so why don’t you use Clusterware to configure your catalog as a single instance in cold failover?

OTN has a very nice whitepaper describing how to protect a single instance database. This can be nicely applied on 10g, 10gR2 or 11g: Using Oracle Clusterware to Protect A Single Instance Oracle Database 11g.

Clusterware is appealing also for traditional cold failover clusters. Licensing allows you to use Clusterware as far as you protect Oracle software or 3rd party software that use Oracle as database backend.

Quick Oracle Dataguard check script

Oracle Dataguard has his own command-line dgmgrl to check the whole dataguard configuration status.
At least you should check that the show configuration command returns SUCCESS.

This is an hypothetic script:

Another script should check for the gap between production online log and the log stream received by the standby database. This can be accomplished with v$managed_standby view.
The Total Block Gap between production and standby can be calculated this way:
Sum all blocks from v$archived_logs where seq# between Current Standby Seq# and Current Production Seq#. Then add current block# of the production LGWR process and subtract current block# from RFS standby process. This gives you total blocks even if there is a log sequence gap between sites.
This is NOT the gap of online log APPLIED to the standby database. THIS IS THE GAP OF ONLINE LOG TRANSMITTED TO THE STANDBY RFS PROCESS and can be used to monitor your dataguard transmission from production to disaster recovery environment.

This is an excerpt of such script (please take care that it does not check against RFS failures, so it can fails when RFS is not alive):

Any comment is appreciated!

Tips: Bash Prompt and Oracle

You may want to check the NEW VERSION of this prompt here.

I disagree with default bash prompt. Do you? It’s quote common to work with long paths:

and, when working on multi-database environments I need to check my environment:

I currently use this prompt, instead:

What is ohvers?? I defined this function to get the version of oracle from my ORACLE_HOME variable:

Pros:

  • I have a blank line that separate my prompt from previous output
  • I get the system clock (useful when saving my konsole history. Did I say konsole?)
  • I can see my Oracle Environment before launching dangerous commands
  • I have an empty line to start my endless commands
  • I have a lot of sharps “#” : they are fine against wrong copy&paste operations…

Suggestions?