Mysql Problem, Operating system error number 13 in a file operation

Posted by cikul | Posted in Linux, SQL | Posted on 31-07-2017-05-2008


Mysql Fail to start, check in /var/log/mysqld.log :

170731 16:56:50 InnoDB: Initializing buffer pool, size = 8.0M
170731 16:56:50 InnoDB: Completed initialization of buffer pool
170731 16:56:50 InnoDB: Operating system error number 13 in a file operation.
InnoDB: The error means mysqld does not have the access rights to
InnoDB: the directory.
InnoDB: File name ./ibdata1
InnoDB: File operation call: 'open'.
InnoDB: Cannot continue operation.
170731 16:56:50 mysqld_safe mysqld from pid file /var/run/mysqld/ ended


Cause :

Permission problem in /var/lib/mysql

Solutions :

  1. Ensure user and group permission on /var/lib/mysql is mysql
  2. Check SELINUX Configuration : getenforce
  3. If SELINUX enabled, disabled with command : setenforce 0
  4. For permanent disable, edit /etc/selinux/config and set SELINUX=disabled
  5. Try to restart mysql service

Change & Reset Mysql Password

Posted by cikul | Posted in Linux, SQL, Tips | Posted on 18-10-2015-05-2008


This tutorial explains how to change or reset your MySQL root password under Unix-Like Operating Systems (Linux, FreeBSD, OpenBSD, etc) over SSH. MySQL root account should be managed carefully.

As a system administrator, we must ensure that the password is safe and prevent from unauthorized access.

There are some method to change mysql password :

Type 1 : use mysqladmin

However, if you want to change mysql root/user password, mysql had tool to simplify the process using mysqladmin command, the syntax is :

$ mysqladmin -u root -p'oldpassword' password newpass
$ mysqladmin -u dbuser -p'oldpassword' password 'itsnewpassword';

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[Oracle] Automatically Kill inactive Sessions

Posted by cikul | Posted in Oracle, Programming, SQL, Technology | Posted on 28-09-2012-05-2008


The problem you could face with arbitrary killing of inactive sessions is that you may kill a session that was still running (it could have just completed one procedure & hadn’t yet started another).

Perhaps an easier way to accomplish what you want (although I’m guessing here at what it is you want to do!) is to set the users’ profiles to automatically kill their session after a specified period of time e.g.

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[Oracle] instance recovery required, cannot set ARCHIVELOG mode

Posted by cikul | Posted in Oracle, SQL, Technology | Posted on 26-09-2012-05-2008


When I try to set archivelog in another machine using this guidance. I’ve got this error message :

SQL> startup mount;
ORACLE instance started.

Total System Global Area  320309648 bytes
Fixed Size                   731536 bytes
Variable Size             285212672 bytes
Database Buffers           33554432 bytes
Redo Buffers                 811008 bytes
Database mounted.
SQL> alter database archivelog;
alter database archivelog
ERROR at line 1:
ORA-00265: instance recovery required, cannot set ARCHIVELOG mode

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[Oracle] Setting ArchiveLog mode

Posted by cikul | Posted in Oracle, SQL | Posted on 25-09-2012-05-2008


What Is Archive Log?

As a DBA, you are responsible to recover any failures to a point of failure and also to perform your backup while online. Your organization is a 24×7 shop and you are not able to shutdown the database. Therefore, the database has to be in an archive mode.

For example you have severe corruption or a database crash that required you to restore some datafiles from several hours ago. If you have all the archived logs from that pint in time up until the moment of the crash, you can roll forward all the changes contained in those archived logs against the restored datafiles.

This process will replays all the changes in the database over the past hours. After recovering the last archived log, Oracle will then look to roll forward even more by using the online redo logs. If those online redo logs contain changes necessary, Oracle will apply those changes also.

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[Oracle] Troubleshoot “Connected to an idle instance.”

Posted by cikul | Posted in Linux, Oracle, SQL, Windows | Posted on 24-09-2012-05-2008


Problem : You have an Oracle instance, and you know it’s running on the system, when you’re trying to connect using “/ as sysdba” it says the instance is idle. You know the database is up and opened, because your application’s talking to it.

[oracle@server db_1]$ sqlplus / as sysdba
SQL*Plus: Release - Production on Mon Sep 24 15:22:47 2012
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
Connected to an idle instance.

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[Oracle] Startup & Shutdown Oracle Instance

Posted by cikul | Posted in Oracle, SQL | Posted on 17-07-2012-05-2008


For DBA,  starting up and shutting down database is a routine operation. How to start and stop Oracle database (windows & Unix base)

Starting Up Oracle Database

To starting up Oracle Database,  you must connect using SQLPLUS /as sysdba or an oracle account that has DBA privilege.

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[SQL-Oracle] Copying data from one table to another

Posted by cikul | Posted in SQL | Posted on 29-06-2012-05-2008


How to simply copy data from one Oracle table into another one? There is several ways to copy data, the common usage is exporting the data and then reupload the data to new table.

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Query data from specific date SQL Server

Posted by cikul | Posted in SQL, Tips | Posted on 01-03-2012-05-2008


for example, you have sort of data from table order :

Order id Order_date Value
1 2005-12-15 13:04:42.667 500
2 2006-03-16 19:08:30.423 350
3 2007-07-28 15:14:30.350 400
4 2006-03-16 20:11:25.413 150
5 2000-09-10 16:09:58.817 200

and you want to get data for date 2006-03-16,

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