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If you got this error when trying to open an Oracle database SQL> alter database open; ORA-10873: file 1 needs to be either taken out of backup mode or media recovered ... As the error message said, you need to move the file out of backup mode: SQL> startup  mount ; //if the db is not mounted yet SQL> alter database end backup ; then you will be able to open the Oracle db: SQL> alter database open ;

This morning, when I was trying to troubleshoot the Oracle database using sqlplus console I got this error: ORA-01109 database not open So I need to open the database: C:\> sqlplus /@PSPRODDB as sysdba SQL> select status from v$instance; the result should be MOUNTED . If not, try: SQL> startup  mount; Then SQL> alter database open; References: https://community.oracle.com/thread/320757?tstart=0

To enable Staff Graded Assignment xblock in your Open EdX instance: 1. Install EDX-SGA: * Install sga to edx-platform: sudo -H -u edxapp bash source /edx/app/edxapp/edxapp_env cd /edx/app/edxapp/venvs/edxapp/src git clone  https://github.com/ mitodl/edx- sga cd edx- sga python setup.py install  cp -R templates/ /edx/app/edxapp/venvs/edxapp/ local/lib/python2.7/site- packages/edx_sga-0.2.0-py2.7. egg/ * Add 'edx_sga' to INSTALLED_APPS in cms/env/common.py and lms/env/common.py * Migrate the db: LMS: sudo -u www-data /edx/bin/python.edxapp ./manage.py lms syncdb --migrate --settings aws CMS: sudo -u www-data /edx/bin/python.edxapp ./manage.py cms syncdb --migrate --settings aws 2. In edx-platform/cms/envs/common.py and edx-platform/lms/envs/common.py , uncomment:   # from xmodule.x_module import prefer_xmodules   # XBLOCK_SELECT_FUNCTION = prefer_xmodules   3. In edx-platform/cms/envs/common.py , change: 'ALLOW_ALL_ADVAN...

On July 20th, MIT's Office of Digital learning has released an XBlock for a Staff Graded Assignment ( SGA ). When placed in a course, this XBlock allows students to upload documents which can be viewed and graded by course staff. Git repository: https://github.com/mitodl/edx-sga But after I enabled the XBlock successfully, I could not upload the assignment file to the sga xblock (stop at 100%): I checked the log and found this: File "/ edx /app/edxapp/venvs/edxapp/ local/lib/python2.7/site- packages/boto/s3/connection. py", line 174, in __init__     validate_certs=validate_certs)   File "/ edx /app/edxapp/venvs/edxapp/ local/lib/python2.7/site- packages/boto/connection.py", line 557, in __init__     host, config, self.provider, self._required_auth_ capability())   File "/ edx /app/edxapp/venvs/edxapp/ local/lib/python2.7/site- packages/boto/auth.py", line 728, in get_auth_handler     'Check your credentials' % (len(names)...

If someday you plug a device which does not have a display (something like a monitor) into your LAN network and don't know where it is on the network (IP address), E.g my Beaglebone Black, you can use nmap. Nmap is a free network scanner utility. $ sudo nmap -sn 172.18.0.0/16 (scan the 172.18.0.0 network, my LAN network, to find the device) The results are something like: I can see one Texas Instruments device which is my Beaglebone Black's network chip manufacturer. So, that is my board.

In the past, It was not easy to get the custom fields data from PowerSchool's Oracle database because of the way it architected and organized custom fields data (they are stored as views in Oracle). With the newer version of PowerSchool (v7.9 and above), you can create custom fields to the extension database table. You can even migrate all the legacy custom fields (students and teachers/ school staffs) to that new location. It makes my life much easier when I want to manipulate those custom fields data because from now on, all the students custom fields data will be stored in 1 place, and the same for teachers's custom fields. * Student custom fields data will be stored in U_STUDENTSUSERFIELDS table * Teacher custom fields data will be stored in U_SCHOOLSTAFFUSERFIELDS table For example, you can use this script (python, SQLAlchemy, cx_Oracle) to export students data from PowerSchool along with any custom fields data you want: PowerSchool DATABASE Connector:

If you don't care about rabbitmq clustering like I do, you can setup rabbitmq to listen connections from localhost only: $ sudo nano /etc/rabbitmq/rabbitmq-env.conf RABBITMQ_NODE_PORT=5672 RABBITMQ_NODE_IP_ADDRESS=127.0.0.1 RABBITMQ_NODENAME=rabbit@myhostname (RabbitMQ 3.3.4) References:  [0] http://serverfault.com/questions/235669/how-do-i-make-rabbitmq-listen-only-to-localhost [1]  http://gigisayfan.blogspot.com/2012/06/rabbit-mq-clustering-python-fabric.html

Love the Python REPL interface? Wanna do something like that in PHP? Let's try Boris , the missing PHP REPL: https://github.com/d11wtq/boris To install boris in Ubuntu (I'm using v14.04), the easiest way is to  clone the git repository: $ git clone git://github.com/d11wtq/boris.git $ cd boris $ sudo ln -s /path/to/boris/bin/boris /usr/local/bin/boris Now you can test-drive your PHP code in command line without writing all the code at one.

To work with Oracle DBMS using PHP you need to install oci8 extension. 0. Install Oracle client instant: http://www.oracle.com/technetwork/topics/linuxx86-64soft-092277.html The Oracle instant client will be installed at  /usr/lib/oracle/12.1/client64 Export the ORACLE_HOME and  $LD_LIBRARY_PATH  environment variable: $ export ORACLE_HOME=/usr/lib/oracle/12.1/client64 $ export LD_LIBRARY_PATH=$ORACLE_HOME/lib Read my blog post about oracle 12c instant client at  http://iambusychangingtheworld.blogspot.com/2014/07/install-cxoracle-513-in-ubuntu-1404.html 1. Install php-pear (needed by pecl) and php5-dev: $ sudo apt-get install pear $ sudo apt-get install php5-dev 2. Install oci8 extension using pecl: $ sudo pecl install oci8 This will ask for Oracle Home Directory – give the path of the instant client: 'instantclient,/usr/lib/oracle/12.1/client64/lib' 3. Enable oci8 in php.ini: $ sudo echo "extension=oci8.so" >> /etc/php5/f...

Yesterday, I's trying to enable the THIRD_PARTY_AUTH feature of the OpenEdX following these article of the author: Overview of the feature: http://johnmcox.blogspot.com/2014/05/getting-started-with-edx-third-party.html To understand how the feature works in OpenEdX: http://johnmcox.blogspot.com/2014/05/understanding-edx-third-party.html I did everything the author said to enable the third party authentication feature to allow my users at UnSchool using their GMail or LinkedIn account to log in to our OpenEdX, including: 1. I did enable the feature in the /edx/app/edxapp/lms.env.json: ...     "FEATURES": {         "ENABLE_THIRD_PARTY_AUTH": true,         "AUTH_USE_OPENID_PROVIDER": true,         "AUTOMATIC_AUTH_FOR_TESTING": false, ... 2. Create Google and LinkedIn apps, then fill in the /edx/app/edxapp/lms.auth.json with keys and secrets of these apps (at the end of the json): ...   ...

Understand how PowerSchool works is very important if you're working as a developer at a school which is using PowerSchool as the Student Information System. PowerSchool is a big web application with a lot of components working together. It will take a huge amount of time to master all of them, so to get started, I will go through the admin login process of PowerSchool. 1. The first time you access the admin login page (http://mydomain.com/admin/pw.html), PowerSchool will give you a random token, pstoken input field of LoginForm: <input type="hidden" name="pstoken" value=" 20233460462xtw69pPuoIBNJ1RyLBnKsfuykVNlJzd "> 2. The admin user input username and password into the form (in the form of < username;password >), and press submit button. 3. Before the form's data is sent to PowerSchool server, the password is hashed using base64 md5 and then hashed again with the token provided in step (1) If the user is a ldap user, the l...

To be able to install cx_Oracle 5.1.3  (to manipulate an Oracle 12c database with python) in Ubuntu 14.04 with oracle-instantclient12.1 succesfully, you have to do following things: 1. Download these instant client packages from http://www.oracle.com/technetwork/topics/linuxx86-64soft-092277.html : oracle-instantclient12.1-tools-12.1.0.1.0-1.x86_64.rpm oracle-instantclient12.1-odbc-12.1.0.1.0-1.x86_64.rpm oracle-instantclient12.1-devel-12.1.0.1.0-1.x86_64.rpm oracle-instantclient12.1-sqlplus-12.1.0.1.0-1.x86_64.rpm oracle-instantclient12.1-jdbc-12.1.0.1.0-1.x86_64.rpm oracle-instantclient12.1-basic-12.1.0.1.0-1.x86_64.rpm (the packages that are in red are required) 2. Convert all rpm packages to deb using alien: $ sudo alien -d *.rpm 3. Install all those deb packages: $ sudo dpkg -i *.deb 4. Create the ORACLE_HOME environment variable: Create a file: /etc/ld.so.conf.d/oracle.conf and in the first line of the script, write (it depends on you...

I was trying to convert a rpm package to deb package using alien and I got this error: $ sudo alien -d mypackage.rpm error: db5 error(-30969) from dbenv->open: BDB0091 DB_VERSION_MISMATCH: Database environment version mismatch error: cannot open Packages index using db5 -  (-30969) error: cannot open Packages database in /home/trinh/.rpmdb ... It is because this is the first time I run alien on Ubuntu and the system did not have any rpm database. So, to get rid of the error, run the following command to install RPM DB: sudo rpm --rebuilddb

After a while, your MySQL databases will be fragmented, and you need to run the MySQL optimization to defrag it. A guy name Phil Dufault had written a shell script which can find all the fragmented tables in your databases and defrag them for you: The author's repo: https://github.com/pdufault/mysqlfragfinder Create a crontab to run that script periodically on a given schedule. For example: # crontab -e ... 22 4 * * 0 /usr/local/bin/mysqlfragfinder.sh  --user root --password mySuperPassword ... That crontab will run the mysqlfragfinder.sh at 4:22 AM every Sunday.

I saw this error in the xqueue's log: /edx/var/log/xqueue/edx.log: Traceback (most recent call last):   File "/edx/app/xqueue/venvs/xqueue/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 111, in get_response     response = callback(request, *callback_args, **callback_kwargs)   File "/edx/app/xqueue/venvs/xqueue/local/lib/python2.7/site-packages/django/contrib/auth/decorators.py", line 20, in _wrapped_view     return view_func(request, *args, **kwargs)   File "/edx/app/xqueue/venvs/xqueue/local/lib/python2.7/site-packages/statsd.py", line 97, in wrapped     result = func(*args, **kwargs)   File "/edx/app/xqueue/xqueue/queue/ext_interface.py", line 39, in get_queuelen     job_count = queue.producer.get_queue_length(queue_name)   File "/edx/app/xqueue/xqueue/queue/producer.py", line 62, in get_queue_length     return push_to_queue(queue_name)   File "/edx/app/xqueue/xqueue/que...

This morning, the comments service of our OpenEdX instance stopped working. Noone could post comment or replied in a thread:  Because the forum data is stored in mongodb, so I first try to look into that database, found out that the user I use for the comment service was disappeared?!! So, I tried to create that user and hopefully, the forum worked again: 1. Login to mongodb cli by typing in " mongo " in your linux console ( not sure how to do it in windows or MacOSX) $ sudo mongo 2. In mongodb cli, switch to the forum db: > use mydb 3. Check the existence of myuser user using for the forum service: > show users 4. If there is no user names myuser, create one (mongodb 2.4, http://docs.mongodb.org/v2.4/ reference/method/db.addUser/# db.addUser ): > db.addUser({user: "myuser", pwd: "mypassword", roles: ["readWrite", "dbAdmin"] }) 5. You may have to restart the forum service (or ev...