Monday, January 15, 2018

ORA-12519, TNS:no appropriate service handler found


Caused by: oracle.net.ns.NetException: Listener refused the connection with the following error:
ORA-12519, TNS:no appropriate service handler found
 

SQL> set lines 200
SQL> select * from v$resource_limit where resource_name = 'processes';
RESOURCE_NAME                  CURRENT_UTILIZATION MAX_UTILIZATION INITIAL_ALLOCATION                       LIMIT_VALUE                                  CON_ID
------------------------------ ------------------- --------------- ---------------------------------------- ---------------------------------------- ----------
processes                                      988            1000       1000                                     1000                                        0

SQL> select count(1) FROM v$session;

  COUNT(1)
----------
       969

SQL> select status,count(1) FROM v$session group by status;

STATUS     COUNT(1)
-------- ----------
ACTIVE           46
INACTIVE        923


We have seen lots if INACTIVE sessions which we need to kill.  After killing sessions that were INACTIVE for a very long time. We don't see the errors anymore after re-executing the deployment.

SQL> select status,count(1) FROM v$session group by status;

STATUS     COUNT(1)
-------- ----------
ACTIVE           46
INACTIVE        310

SQL> select count(1) FROM v$session;

  COUNT(1)
----------
       356

SQL>




Vagrant was unable to mount VirtualBox shared folders

I got this error below while starting vagrant. I am dependent on using CLI in  my work so i need to find a solution. 

C:\>vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Checking if box 'bento/centos-7.3' is up to date...
==> default: Clearing any previously set forwarded ports...
==> default: Clearing any previously set network interfaces...
==> default: Preparing network interfaces based on configuration...
    default: Adapter 1: nat
==> default: Forwarding ports...
    default: 22 (guest) => 2222 (host) (adapter 1)
==> default: Booting VM...
==> default: Waiting for machine to boot. This may take a few minutes...
    default: SSH address: 127.0.0.1:2222
    default: SSH username: vagrant
    default: SSH auth method: private key
    default: Warning: Connection reset. Retrying...
    default: Warning: Connection aborted. Retrying...
    default: Warning: Connection reset. Retrying...
    default: Warning: Connection aborted. Retrying...
    default: Warning: Connection reset. Retrying...
    default: Warning: Connection aborted. Retrying...
    default: Warning: Connection reset. Retrying...
    default: Warning: Connection aborted. Retrying...
    default: Warning: Connection reset. Retrying...
    default: Warning: Remote connection disconnect. Retrying...
    default: Warning: Connection aborted. Retrying...
    default: Warning: Connection reset. Retrying...
==> default: Machine booted and ready!
==> default: Checking for guest additions in VM...
    default: No guest additions were detected on the base box for this VM! Gues

    default: additions are required for forwarded ports, shared folders, host o
ly
    default: networking, and more. If SSH fails on this machine, please install
    default: the guest additions and repackage the box to continue.
    default:
    default: This is not an error message; everything may continue to work prop
rly,
    default: in which case you may ignore this message.
==> default: Mounting shared folders...
    default: /vagrant => C:/
Vagrant was unable to mount VirtualBox shared folders. This is usually
because the filesystem "vboxsf" is not available. This filesystem is
made available via the VirtualBox Guest Additions and kernel module.
Please verify that these guest additions are properly installed in the
guest. This is not a bug in Vagrant and is usually caused by a faulty
Vagrant box. For context, the command attempted was:

mount -t vboxsf -o uid=1000,gid=1000 vagrant /vagrant

The error output from the command was:

/sbin/mount.vboxsf: mounting failed with the error: No such device


Found some discussions in the stackoverflow. And i tried 1 solution below.


C:\>vagrant plugin install vagrant-vbguest
Installing the 'vagrant-vbguest' plugin. This can take a few minutes...
Fetching: vagrant-share-1.1.9.gem (100%)
Fetching: micromachine-2.0.0.gem (100%)
Fetching: vagrant-vbguest-0.15.1.gem (100%)
Installed the plugin 'vagrant-vbguest (0.15.1)'!

I tried to reinstall it again since i forgot to shut it down first before i install the vagrant-vbgust plugin. 

C:\>vagrant halt
==> default: Attempting graceful shutdown of VM...

Since i was already installed in the first run it does not do anything.

C:\>vagrant plugin install vagrant-vbguest
Installing the 'vagrant-vbguest' plugin. This can take a few minutes...
Installed the plugin 'vagrant-vbguest (0.15.1)'!

Then i started the vagrant. After starting it the vagrant reinstalled some libraries.


C:\>vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Checking if box 'bento/centos-7.3' is up to date...
==> default: Clearing any previously set forwarded ports...
==> default: Clearing any previously set network interfaces...
==> default: Preparing network interfaces based on configuration...
    default: Adapter 1: nat
==> default: Forwarding ports...
    default: 22 (guest) => 2222 (host) (adapter 1)
==> default: Booting VM...
==> default: Waiting for machine to boot. This may take a few minutes...
    default: SSH address: 127.0.0.1:2222
    default: SSH username: vagrant
    default: SSH auth method: private key
    default: Warning: Connection reset. Retrying...
    default: Warning: Connection aborted. Retrying...
    default: Warning: Connection reset. Retrying...
    default: Warning: Connection aborted. Retrying...
    default: Warning: Connection reset. Retrying...
    default: Warning: Connection aborted. Retrying...
    default: Warning: Remote connection disconnect. Retrying...
    default: Warning: Connection reset. Retrying...
    default: Warning: Connection aborted. Retrying...
    default: Warning: Connection reset. Retrying...
==> default: Machine booted and ready!
[default] No installation found.
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: ftp.tsukuba.wide.ad.jp
 * extras: ftp.tsukuba.wide.ad.jp
 * updates: ftp.tsukuba.wide.ad.jp
Package binutils-2.25.1-32.base.el7_4.1.x86_64 already installed and latest vers
ion
Package 1:make-3.82-23.el7.x86_64 already installed and latest version
Package 4:perl-5.16.3-292.el7.x86_64 already installed and latest version
Package bzip2-1.0.6-13.el7.x86_64 already installed and latest version
Resolving Dependencies
--> Running transaction check
---> Package gcc.x86_64 0:4.8.5-16.el7_4.1 will be installed
--> Processing Dependency: cpp = 4.8.5-16.el7_4.1 for package: gcc-4.8.5-16.el7_
4.1.x86_64
--> Processing Dependency: glibc-devel >= 2.2.90-12 for package: gcc-4.8.5-16.el
7_4.1.x86_64
---> Package kernel-devel.x86_64 0:3.10.0-693.11.6.el7 will be installed
--> Running transaction check
---> Package cpp.x86_64 0:4.8.5-16.el7_4.1 will be installed
---> Package glibc-devel.x86_64 0:2.17-196.el7_4.2 will be installed
--> Processing Dependency: glibc-headers = 2.17-196.el7_4.2 for package: glibc-d
evel-2.17-196.el7_4.2.x86_64
--> Processing Dependency: glibc-headers for package: glibc-devel-2.17-196.el7_4
.2.x86_64
--> Running transaction check
---> Package glibc-headers.x86_64 0:2.17-196.el7_4.2 will be installed
--> Processing Dependency: kernel-headers >= 2.2.1 for package: glibc-headers-2.
17-196.el7_4.2.x86_64
--> Processing Dependency: kernel-headers for package: glibc-headers-2.17-196.el
7_4.2.x86_64
--> Running transaction check
---> Package kernel-headers.x86_64 0:3.10.0-693.11.6.el7 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
================================================================================
 Package             Arch        Version                     Repository    Size
================================================================================
Installing:
 gcc                 x86_64      4.8.5-16.el7_4.1            updates       16 M
 kernel-devel        x86_64      3.10.0-693.11.6.el7         updates       14 M
Installing for dependencies:
 cpp                 x86_64      4.8.5-16.el7_4.1            updates      5.9 M
 glibc-devel         x86_64      2.17-196.el7_4.2            updates      1.1 M
 glibc-headers       x86_64      2.17-196.el7_4.2            updates      676 k
 kernel-headers      x86_64      3.10.0-693.11.6.el7         updates      6.0 M
Transaction Summary
================================================================================
Install  2 Packages (+4 Dependent packages)
Total download size: 44 M
Installed size: 95 M
Downloading packages:
Delta RPMs disabled because /usr/bin/applydeltarpm not installed.
--------------------------------------------------------------------------------
Total                                              2.8 MB/s |  44 MB  00:15
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : kernel-headers-3.10.0-693.11.6.el7.x86_64                    1/6
  Installing : glibc-headers-2.17-196.el7_4.2.x86_64                        2/6
  Installing : glibc-devel-2.17-196.el7_4.2.x86_64                          3/6
  Installing : cpp-4.8.5-16.el7_4.1.x86_64                                  4/6
  Installing : gcc-4.8.5-16.el7_4.1.x86_64                                  5/6
  Installing : kernel-devel-3.10.0-693.11.6.el7.x86_64                      6/6
  Verifying  : cpp-4.8.5-16.el7_4.1.x86_64                                  1/6
  Verifying  : glibc-devel-2.17-196.el7_4.2.x86_64                          2/6
  Verifying  : kernel-devel-3.10.0-693.11.6.el7.x86_64                      3/6
  Verifying  : glibc-headers-2.17-196.el7_4.2.x86_64                        4/6
  Verifying  : gcc-4.8.5-16.el7_4.1.x86_64                                  5/6
  Verifying  : kernel-headers-3.10.0-693.11.6.el7.x86_64                    6/6

Installed:
  gcc.x86_64 0:4.8.5-16.el7_4.1    kernel-devel.x86_64 0:3.10.0-693.11.6.el7
Dependency Installed:
  cpp.x86_64 0:4.8.5-16.el7_4.1
  glibc-devel.x86_64 0:2.17-196.el7_4.2
  glibc-headers.x86_64 0:2.17-196.el7_4.2
  kernel-headers.x86_64 0:3.10.0-693.11.6.el7

Complete!
Copy iso file C:\Program Files\Oracle\VirtualBox\VBoxGuestAdditions.iso into the
 box /tmp/VBoxGuestAdditions.iso
Mounting Virtualbox Guest Additions ISO to: /mnt
mount: /dev/loop0 is write-protected, mounting read-only
Installing Virtualbox Guest Additions 5.1.28 - guest version is unknown
Verifying archive integrity... All good.
Uncompressing VirtualBox 5.1.28 Guest Additions for Linux...........
VirtualBox Guest Additions installer
Removing installed version 5.1.26 of VirtualBox Guest Additions...
Copying additional installer modules ...
Installing additional modules ...
vboxadd.sh: Starting the VirtualBox Guest Additions.
Could not find the X.Org or XFree86 Window System, skipping.
Redirecting to /bin/systemctl start vboxadd.service
Redirecting to /bin/systemctl start vboxadd-service.service
Unmounting Virtualbox Guest Additions ISO from: /mnt
==> default: Checking for guest additions in VM...
==> default: Mounting shared folders...
    default: /vagrant => C:/
==> default: Machine already provisioned. Run `vagrant provision` or use the `--
provision`
==> default: flag to force provisioning. Provisioners marked to run always will
still run.

After everything was done tried to access vagrant via PUTTY and now the my local drive is now accessible via vagrant. How cool is that!!!!! 

Just another issue while browsing my local directory via vagrant. I throws an error while browsing some Windows default directory. I am not sure why but the important thing is i am able to access my Work directory.

[root@localhost vagrant]# ls -ltr
ls: cannot read symbolic link Documents and Settings: Protocol error
total 14211895
-rwxrwxrwx. 1 vagrant vagrant       5686 Nov  7  2007 vcredist.bmp

.

Friday, February 14, 2014

Innotop on Centos 6.5 MySQL version 5.5.34

innotop - MySQL and InnoDB transaction/status monitor.

INSTALLATION

wget https://innotop.googlecode.com/files/innotop-1.9.1-1.el6.noarch.rpm
rpm -ivh innotop-1.9.1-1.el6.noarch.rpm

Posible errros:

error: Failed dependencies:
        perl(Term::ReadKey) is needed by innotop-1.9.1-1.el6.noarch
        perl(Time::HiRes) is needed by innotop-1.9.1-1.el6.noarch
        perl-TermReadKey is needed by innotop-1.9.1-1.el6.noarch
        perl-Time-HiRes is needed by innotop-1.9.1-1.el6.noarch

more info about innotop: http://innotop.googlecode.com/svn/html/manual.html



[root@mercury tmp]# yum install perl-TermReadKey
Loaded plugins: fastestmirror, refresh-packagekit, security
Loading mirror speeds from cached hostfile
 * base: centos.mirrors.hoobly.com
 * extras: mirrors.xmission.com
 * updates: centos.eecs.wsu.edu
 * webtatic: us-east.repo.webtatic.com
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package perl-TermReadKey.x86_64 0:2.30-13.el6 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

==============================================================================================================================================
 Package                                 Arch                          Version                              Repository                   Size
==============================================================================================================================================
Installing:
 perl-TermReadKey                        x86_64                        2.30-13.el6                          base                         31 k

Transaction Summary
==============================================================================================================================================
Install       1 Package(s)

Total download size: 31 k
Installed size: 62 k
Is this ok [y/N]: y
Downloading Packages:
perl-TermReadKey-2.30-13.el6.x86_64.rpm                                                                                |  31 kB     00:00
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : perl-TermReadKey-2.30-13.el6.x86_64                                                                                        1/1
  Verifying  : perl-TermReadKey-2.30-13.el6.x86_64                                                                                        1/1

Installed:
  perl-TermReadKey.x86_64 0:2.30-13.el6

Complete!
[root@mercury tmp]# yum install perl-Time-HiRes
Loaded plugins: fastestmirror, refresh-packagekit, security
Loading mirror speeds from cached hostfile
 * base: centos.mirrors.hoobly.com
 * extras: mirrors.xmission.com
 * updates: centos.eecs.wsu.edu
 * webtatic: us-east.repo.webtatic.com
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package perl-Time-HiRes.x86_64 4:1.9721-136.el6 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

==============================================================================================================================================
 Package                               Arch                         Version                                  Repository                  Size
==============================================================================================================================================
Installing:
 perl-Time-HiRes                       x86_64                       4:1.9721-136.el6                         base                        48 k

Transaction Summary
==============================================================================================================================================
Install       1 Package(s)

Total download size: 48 k
Installed size: 56 k
Is this ok [y/N]: y
Downloading Packages:
perl-Time-HiRes-1.9721-136.el6.x86_64.rpm                                                                              |  48 kB     00:01
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : 4:perl-Time-HiRes-1.9721-136.el6.x86_64                                                                                    1/1
  Verifying  : 4:perl-Time-HiRes-1.9721-136.el6.x86_64                                                                                    1/1

Installed:
  perl-Time-HiRes.x86_64 4:1.9721-136.el6

Complete!


[root@mercury tmp]# rpm -ivh innotop-1.9.1-1.el6.noarch.rpm
Preparing...                ########################################### [100%]
   1:innotop                ########################################### [100%]

Mytop on Centos 6.5 Mysql Version : 5.5.34



Mytop

mytop is a console-based (non-gui) tool for monitoring the threads
and overall performance of a MySQL server.
It runs on most Unix systems which have Perl,
DBI, and Term::ReadKey installed. And with Term::ANSIColor installed
you even get color.

If you install Time::HiRes, you’ll get good real-time queries/second stats.

As of version 0.7, it even run

INSTALLATIONS

Download Package: http://jeremy.zawodny.com/mysql/mytop/
tar -zxvf mytop-.tar.gz
cd mytop-
perl Makefile.PL
make
make install


Possible Errors during installation:

Warning: prerequisite DBD::mysql 1 not found.
Warning: prerequisite DBI 1.13 not found.
Warning: prerequisite Term::ReadKey 2.1 not found.

Solution:

perl-Class-Data-Inheritable-0.08-1.el5.rf.noarch.rpm
perl-DBD-MySQL-4.014-1.el5.rfx.x86_64.rpm
perl-DBI-1.616-1.el5.rfx.x86_64.rpm
perl-DBIx-ContextualFetch-1.03-1.el5.rf.noarch.rpm
perl-Ima-DBI-0.35-1.el5.noarch.rpm
perl-Ima-DBI-0.35-1.el5.src.rpm
perl-TermReadKey-2.30-4.el5.

Error after a successful installation:

Use of uninitialized value $host in substitution (s///) at /usr/local/bin/mytop line 958.

Solution:

Remove this line

        $host =~ s/^([^.]+).*/$1/;
        $thread->{Host} = $host;

Replace with this

            if ($host)
                {
              $host =~ s/^([^.]+).*/$1/;
              $thread->{Host} = $host;
                }



Error in option spec: "long|!"

Solution:

The fix for this is to edit the mytop script and comment out the line containing long|!

vi /usr/local/bin/mytop

Run a search for long|! and comment out the following line:

"long|!" => \$config{long_nums},

Start mytop and you should be fine.



Sources: 

Thursday, February 13, 2014

MySQL 5.5 Installation on Centos/RHEL 6.5 via Yum

I've been using RPM every time i will install MySQL server in my Linux boxes. But today i will show you on how to install MySQL 5.5 on Centos 6.5 via Yum.

First, to set up the yum repository, install the webtatic-release RPM based on your CentOS/RHEL release.


[root@localhost ~]# rpm -Uvh http://mirror.webtatic.com/yum/el6/latest.rpm
Retrieving http://mirror.webtatic.com/yum/el6/latest.rpm
warning: /var/tmp/rpm-tmp.q3Y9pR: Header V4 DSA/SHA1 Signature, key ID cf4c4ff9: NOKEY
Preparing...                ########################################### [100%]

   1:webtatic-release       ########################################### [100%]



Remove the pre-installed mysql-libs with no dependecy.

[root@localhost ~]# rpm -e  mysql-libs
error: Failed dependencies:
        libmysqlclient.so.16()(64bit) is needed by (installed) postfix-2:2.6.6-2.2.el6_1.x86_64
        libmysqlclient.so.16(libmysqlclient_16)(64bit) is needed by (installed) postfix-2:2.6.6-2.2.el6_1.x86_64
        mysql-libs is needed by (installed) postfix-2:2.6.6-2.2.el6_1.x86_64


[root@localhost ~]# rpm -e  --nodeps mysql-libs

After removing the previous version of mysql-libs you can now start the installation of MYSQL via Yum


[root@localhost ~]# yum install mysql55 mysql55-server

Loaded plugins: fastestmirror, refresh-packagekit, security
Loading mirror speeds from cached hostfile
 * base: centos.corenetworks.net
 * extras: centos.mirror.freedomvoice.com
 * updates: mirrors.usinternet.com
 * webtatic: sp.repo.webtatic.com
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package mysql55.x86_64 0:5.5.34-1.w6 will be installed
--> Processing Dependency: mysql55-libs = 5.5.34-1.w6 for package: mysql55-5.5.34-1.w6.x86_64
---> Package mysql55-server.x86_64 0:5.5.34-1.w6 will be installed
--> Processing Dependency: perl-DBI for package: mysql55-server-5.5.34-1.w6.x86_64
--> Processing Dependency: perl-DBD-MySQL for package: mysql55-server-5.5.34-1.w6.x86_64
--> Processing Dependency: perl(DBI) for package: mysql55-server-5.5.34-1.w6.x86_64
--> Running transaction check
---> Package mysql55-libs.x86_64 0:5.5.34-1.w6 will be installed
--> Processing Dependency: libmysqlclient16 for package: mysql55-libs-5.5.34-1.w6.x86_64
---> Package perl-DBD-MySQL.x86_64 0:4.013-3.el6 will be installed
---> Package perl-DBI.x86_64 0:1.609-4.el6 will be installed
--> Running transaction check
---> Package libmysqlclient16.x86_64 0:5.1.69-1.w6 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

==================================================================================================================================================
 Package                                 Arch                          Version                              Repository                       Size
==================================================================================================================================================
Installing:
 mysql55                                 x86_64                        5.5.34-1.w6                          webtatic                        5.5 M
 mysql55-server                          x86_64                        5.5.34-1.w6                          webtatic                         10 M
Installing for dependencies:
 libmysqlclient16                        x86_64                        5.1.69-1.w6                          webtatic                        1.0 M
 mysql55-libs                            x86_64                        5.5.34-1.w6                          webtatic                        778 k
 perl-DBD-MySQL                          x86_64                        4.013-3.el6                          base                            134 k
 perl-DBI                                x86_64                        1.609-4.el6                          base                            705 k

Transaction Summary
==================================================================================================================================================
Install       6 Package(s)

Total download size: 18 M
Installed size: 82 M
Is this ok [y/N]: y
Downloading Packages:
(1/6): libmysqlclient16-5.1.69-1.w6.x86_64.rpm                                                                             | 1.0 MB     00:06
(2/6): mysql55-5.5.34-1.w6.x86_64.rpm                                                                                      | 5.5 MB     00:45
(3/6): mysql55-libs-5.5.34-1.w6.x86_64.rpm                                                                                 | 778 kB     00:05
(4/6): mysql55-server-5.5.34-1.w6.x86_64.rpm                                                                               |  10 MB     01:13
(5/6): perl-DBD-MySQL-4.013-3.el6.x86_64.rpm                                                                               | 134 kB     00:02
(6/6): perl-DBI-1.609-4.el6.x86_64.rpm                                                                                     | 705 kB     00:06
--------------------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                             130 kB/s |  18 MB     02:22
warning: rpmts_HdrFromFdno: Header V4 DSA/SHA1 Signature, key ID cf4c4ff9: NOKEY
Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-webtatic-andy
Importing GPG key 0xCF4C4FF9:
 Userid : Andy Thompson
 Package: webtatic-release-6-4.noarch (installed)
 From   : /etc/pki/rpm-gpg/RPM-GPG-KEY-webtatic-andy
Is this ok [y/N]: y
warning: rpmts_HdrFromFdno: Header V3 RSA/SHA256 Signature, key ID c105b9de: NOKEY
Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
Importing GPG key 0xC105B9DE:
 Userid : CentOS-6 Key (CentOS 6 Official Signing Key)
 Package: centos-release-6-5.el6.centos.11.1.x86_64 (@anaconda-CentOS-201311272149.x86_64/6.5)
 From   : /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
Is this ok [y/N]: y
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : perl-DBI-1.609-4.el6.x86_64                                                                                                    1/6
  Installing : libmysqlclient16-5.1.69-1.w6.x86_64                                                                                            2/6
  Installing : mysql55-libs-5.5.34-1.w6.x86_64                                                                                                3/6
  Installing : mysql55-5.5.34-1.w6.x86_64                                                                                                     4/6
  Installing : perl-DBD-MySQL-4.013-3.el6.x86_64                                                                                              5/6
  Installing : mysql55-server-5.5.34-1.w6.x86_64                                                                                              6/6
  Verifying  : libmysqlclient16-5.1.69-1.w6.x86_64                                                                                            1/6
  Verifying  : perl-DBD-MySQL-4.013-3.el6.x86_64                                                                                              2/6
  Verifying  : mysql55-libs-5.5.34-1.w6.x86_64                                                                                                3/6
  Verifying  : perl-DBI-1.609-4.el6.x86_64                                                                                                    4/6
  Verifying  : mysql55-5.5.34-1.w6.x86_64                                                                                                     5/6
  Verifying  : mysql55-server-5.5.34-1.w6.x86_64                                                                                              6/6

Installed:
  mysql55.x86_64 0:5.5.34-1.w6                                         mysql55-server.x86_64 0:5.5.34-1.w6

Dependency Installed:
  libmysqlclient16.x86_64 0:5.1.69-1.w6  mysql55-libs.x86_64 0:5.5.34-1.w6  perl-DBD-MySQL.x86_64 0:4.013-3.el6  perl-DBI.x86_64 0:1.609-4.el6

Complete!

After installing, the commands needed to activate it to run at system startup depend on your operating system. On Linux, you can use chkconfig:

[root@localhost ~]# chkconfig --add mysqld

On some Linux systems, the following command also seems to be necessary to fully enable the mysql script:

[root@localhost ~]# chkconfig --level 345 mysqld on

You can now start MySQL as a service.

[root@localhost bin]# service mysqld start
Starting mysqld:                                           [  OK  ]
[root@localhost bin]# ps ax | grep mysql
26597 pts/2    S      0:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --socket=/var/lib/mysql/mysql.sock --pid-file=/var/run/mysqld/mysqld.pid --basedir=/usr --user=mysql
26804 pts/2    Sl     0:00 /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin --user=mysql --log-error=/var/log/mysqld.log --pid-file=/var/run/mysqld/mysqld.pid --socket=/var/lib/mysql/mysql.sock
26836 pts/2    S+     0:00 grep mysql
[root@localhost bin]#








Tuesday, December 11, 2012

MySQL: Localhost vs 127.0.0.1

Yesterday i was trying to connect to MySQL localhost with another port aside from 3306:

mysql -uroot -p -h localhost --port=3390

to my suprise i was login to the default port. My collegue told me that i need to used 127.0.0.1 instead of localhost so i tried it then i search everywhere to find the answer on why oh why its like this until i found a blog that explained the difference between localhost and 127.0.0.1.

source: http://blogs.sakienvirotech.com/index.php/random/2011/08/30/mysql-101-connecting-to-a

With network connections, there are two special addresses that always refer to the machine you are currently using. This is either called 'localhost' or has the IP address of 127.0.0.1.  In general using these is equivalent and interchangeable, and uses a special path through the networking subsystem called the local loopback interface. However MySQL has reserved 'localhost' for the special purpose of indicating the use of a UNIX socket and not use networking.  This can cause some confusion to new users, but if you understand what is going on it is pretty clear.
'localhost' in MySQL uses the UNIX socket and ignores any port you may supply.
127.0.0.1 in MySQL uses networking and requires a port, using the default if you don't supply it.



Tuesday, November 20, 2012

ERROR 1018 (HY000): Can't read dir of '.' (errno: 24)

We encountered an error in MySQl below:

ERROR 1018 (HY000): Can't read dir of '.' (errno: 24)

Upon searching for some solutions at google we found out that the error means 'Too many open files'. Everything you do in linux is a file (or rather a file descriptor). Every mysql connection, every apache connection etc.

To see how many files a user has open try this

sudo lsof -u mysql


edit the file in /etc/security/limits.conf and add these two mysql lines in at the bottom



#@student        -       maxlogins       4
mysql   soft    nofile  4096
mysql   hard    nofile  8192
# End of file



There is some debate as to whether you need to reboot for this to take effect (i say debate, i rebooted, and didnt google for it as i was in a rush ymmv).
Once this is set you need to make some changes in the mysql file as well. Assuming yours lives in /etc/mysql/my.cnf - edit or add these values

open-files-limit = 2048
table_cache            = 512

The table_cache should be researched (start here: http://dev.mysql.com/doc/refman/5.0/en/table-cache.html) and changes monitored. The default value is 64, so 512 should be a safe bet to begin with.


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