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mySQL: How to reset root password

admin — Sun, 05 Feb 2012 22:48:33 +0000

If the password for the mysql “root” user is lost, it’s still possible reset it to some other value.
The restart of the mySQL server will be necessary, of course.

The following should be done:

Stop the server
It could be done normally:

/etc/init.d/mysql stop

or effectively:

ps -ef | grep mysql
...
mysql 25079 1 0 Jan 31 ? 0:00 /usr/bin/mysqld
...
kill -9 25079

Please ensure that the proper process is killed!

Start MySQL server without security checking

mysqld_safe --skip-grant-tables &

Connect to mySQL without password

mysql -u root

Reset mySQL root password

use mysql;
update user set password=PASSWORD("NEW_PASSWORD") where user='root';
flush privileges;

Use the real new password instead of the string “NEW_PASSWORD”.

Restart mySQL server

/etc/init.d/mysql stop
/etc/init.d/mysql start

Check the connection

mysql -u root -p

Oracle: get the tablespace structure

admin — Thu, 19 Jan 2012 09:35:11 +0000

The easiest method to get the tablespace structure is to use the dbms_metadata package:

SET linesize 200 LONG 50000 pagesize 5000

SELECT dbms_metadata.get_ddl('TABLESPACE',tablespace_name )
FROM dba_tablespaces
WHERE tablespace_name IN ( '&your_tablespace' );

Additionally, exp/imp (or expdp/impdp) utilities could be used. They could generate the DDL statements for all objects in the database, which could be very useful.

exp/imp

exp userid=" '/ as sysdba' " rows=n file=my.dmp full=y
imp userid=" '/ as sysdba' " file=my.dmp full=y show=y > full_structure.sql 2>&1

Warning! exp could not get the contents of the encrypted tablespaces.

expdp/impdp

expdp "'/ as sysdba'" dumpfile=mydp.dmp directory=DATA_PUMP_DIR content=metadata_only full=y
impdp "'/ as sysdba'" dumpfile=mydp.dmp directory=DATA_PUMP_DIR sqlfile=full_structure.sql

Oracle: buffer overflow (ORU-10027)

admin — Wed, 06 Apr 2011 13:03:57 +0000

Sometimes it’s necessary to show the output of the PL/SQL script.
Usually the dbms_output package is used:

SET serveroutput ON
DECLARE
i NUMBER ;
BEGIN
i:=0 ;
WHILE i< 100000 LOOP
i:=i+1 ;
dbms_output.put_line('This is just test line #' || TO_CHAR(i) ) ;
END LOOP ;
END;
/

After several thousands lines the following error message is displayed:

ORA-20000: ORU-10027: buffer overflow, limit of 20000 bytes
ORA-06512: at “SYS.DBMS_OUTPUT”, line 32
ORA-06512: at “SYS.DBMS_OUTPUT”, line 97
ORA-06512: at “SYS.DBMS_OUTPUT”, line 112
ORA-06512: at line 8

The error message means, that the internal buffer of dbms_output is full. How to increase it?
The following methods could be used:

...
dbms_package.enable(100000) ;
...

...
SET serveroutput ON SIZE 100000
...

In Oracle 10gR2 the new addition “size unlimited” could be used:

...
SET serveroutput ON SIZE unlimited
...

If these methods do not work, the temporary table could be used:

CREATE SEQUENCE my_output_seq ;
CREATE global TEMPORARY TABLE my_output_table( my_row NUMBER, my_out VARCHAR2(120) ) ;
...
INSERT INTO my_output_table VALUES ( my_output_seq.NEXTVAL, 'This is some string' ) ;
...
SELECT my_out FROM my_output_table ORDER BY my_row ;
DROP TABLE my_output_table ;
DROP SEQUENCE my_output_seq ;

Oracle: how to clone profiles

admin — Thu, 24 Mar 2011 17:00:16 +0000

Here is the simple script for cloning the Oracle profiles.

SET serveroutput ON

DECLARE
CURSOR c_profiles IS
SELECT PROFILE, RESOURCE_NAME, LIMIT
FROM dba_profiles
ORDER BY PROFILE, resource_name;

s_PROFILE dba_profiles.PROFILE%TYPE ;
s_prev_PROFILE dba_profiles.PROFILE%TYPE ;
s_RESOURCE_NAME dba_profiles.RESOURCE_NAME%TYPE ;
s_LIMIT dba_profiles.LIMIT%TYPE ;
BEGIN

s_prev_PROFILE := 'no_such_profile' ;

dbms_output.enable(1000000);
OPEN c_profiles;
LOOP
FETCH c_profiles INTO s_PROFILE,s_RESOURCE_NAME,s_LIMIT ;
IF ( s_prev_profile <> s_profile ) THEN
BEGIN
dbms_output.put_line ( '--');
dbms_output.put_line ( 'create profile "'||s_profile||'" limit ' ||s_RESOURCE_NAME|| ' ' || s_LIMIT||';' ) ;
s_prev_profile := s_profile ;
END;
ELSE
dbms_output.put_line ( 'alter profile "'||s_profile|| '" limit ' ||s_RESOURCE_NAME|| ' ' || s_LIMIT || ';' ) ;
END IF;
EXIT WHEN c_profiles%NOTFOUND ;
END LOOP ;

CLOSE c_profiles ;

END;
/

Output example:

@clone_profile

create profile “DEFAULT” limit COMPOSITE_LIMIT UNLIMITED;
alter profile “DEFAULT” limit CONNECT_TIME UNLIMITED;
alter profile “DEFAULT” limit CPU_PER_CALL UNLIMITED;
alter profile “DEFAULT” limit CPU_PER_SESSION UNLIMITED;
alter profile “DEFAULT” limit FAILED_LOGIN_ATTEMPTS 10;
alter profile “DEFAULT” limit IDLE_TIME UNLIMITED;
alter profile “DEFAULT” limit LOGICAL_READS_PER_CALL UNLIMITED;
alter profile “DEFAULT” limit LOGICAL_READS_PER_SESSION UNLIMITED;
alter profile “DEFAULT” limit PASSWORD_GRACE_TIME 7;
alter profile “DEFAULT” limit PASSWORD_LIFE_TIME 180;
alter profile “DEFAULT” limit PASSWORD_LOCK_TIME 1;

create profile “MONITORING_PROFILE” limit COMPOSITE_LIMIT DEFAULT;
alter profile “MONITORING_PROFILE” limit FAILED_LOGIN_ATTEMPTS UNLIMITED;

Oracle: quotes and quote operator

admin — Tue, 11 Jan 2011 13:45:20 +0000

There are several methods to put the quote into the string.

The first (and very traditional) one: use 2 quotes.

SELECT 'This '' is quote' FROM dual;

If there are more than one quote, it’s difficult to read and write such strings

The second: use chr(39)

SELECT 'This ' || CHR(39) || ' is quote' FROM dual;

The third: put the quote into the variable

DECLARE
s_quote VARCHAR2(1) := '''' ;
BEGIN
dbms_output.put_line('This ' || s_quote || ' is quote' ) ;
END;

And, finally, Oracle 10g has added new feature: quote operator.

SELECT q'[This ' IS quote]' from dual ;

The general form is q’X string X’. Here X is just some character. If the brackets are used, Oracle expects the closing bracket for the end of the string.

Here are the additional examples:

SELECT q'(This ' IS quote)' from dual ;
select q'|This ' is quote|' FROM dual ;
SELECT q'#This ' IS quote#' from dual ;
select q'#This ' is quote#' FROM dual ;
SELECT q'?This ' IS quote?' from dual ;
select q'TThis ' is quoteT' FROM dual ;

Oracle: problem relinking binaries on Solaris

admin — Fri, 24 Dec 2010 11:53:36 +0000

I’ve got the following message relinking the binaries on Solaris:

ld: fatal: dlopen() of support library (libmakestate.so.1) failed with error:

ld.so.1: /usr/ccs/bin/sparcv9/ld: fatal: /usr/lib/libmakestate.so.1: wrong ELF class: ELFCLASS32

The problem was caused by missing 64-bit library libmakestate.so.1 in /usr/lib.

The normal library should look like the following:

[#] file /usr/lib/sparcv9/libmakestate.so.1
libmakestate.so.1: ELF 64-bit MSB dynamic lib SPARCV9 Version 1, dynamically linked, not stripped

If the library does not exist or is incorrect, it should be reinstalled from the package SUNWsprox ( Sun WorkShop Bundled 64-bit make library)

This command checks, if the package is installed in the system:
[#] pkginfo -i SUNWsprox

After installing the package relink works fine.

Oracle: eval function

admin — Thu, 11 Feb 2010 13:40:55 +0000

The function takes some expression as the argument and executes it, returning output in the varchar string

CREATE OR REPLACE FUNCTION eval (expr VARCHAR2) RETURN VARCHAR2
AS
ret VARCHAR2(4000);
BEGIN
EXECUTE IMMEDIATE 'begin :result := ' || expr || '; end;' USING OUT ret;
RETURN ret;
END;
/

The discussion and examples could be found there

Oracle: list of the system events

admin — Wed, 10 Feb 2010 16:17:13 +0000

This piece of code show the list of events, set in the Oracle database

SET serveroutput ON
DECLARE
event_level NUMBER;
BEGIN
dbms_output.enable(20000) ;
FOR i IN 10000..33999 LOOP
sys.dbms_system.read_ev(i,event_level);
IF (event_level > 0) THEN
dbms_output.put_line('Event '||TO_CHAR(i)||' set at level '||
TO_CHAR(event_level));
END IF;
END LOOP;
END;

Oracle: list of the running transactions

admin — Tue, 09 Feb 2010 12:58:22 +0000

This query shows SID, username and start time of the running transaction.
In addition, number of the used blocks is shown.

SELECT a.sid, a.status, a.username, b.xidusn, b.used_urec, b.used_ublk, b.START_TIME
FROM v$session a, v$transaction b
WHERE a.saddr = b.ses_addr
ORDER BY START_TIME DESC;

Oracle: internal sql types

admin — Tue, 09 Feb 2010 12:51:17 +0000

Here is the list of the Oracle SQL types and their internal codes:

SELECT t.typecode,o.name
FROM sys.TYPE$ t, sys.obj$ o
WHERE
BITAND (t.properties, 16) = 16
AND t.toid = o.oid$
ORDER BY t.typecode

‘