Category Archives: TIPS & T RICS

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ORA-12519: TNS:no appropriate service handler found

The number of database processes that can run in Oracle DB is set to 150 as default which can be viewed from v$resource_limit. select * from v$resource_limit where resource_name = ‘processes’; RESOURCE_NAME CURRENT_UTILIZATION MAX_UTILIZATION INITIAL_ALLOCATION LIMIT_VALUE ————- ——————- ————— —————— … Continue reading

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Accessing Host from Docker Container

Sometime we need to access the services that are running in the host machine to be accessible from the docker container.  e.g. In on of my project, we needed to connect to the oracle db (port 1521) from inside the … Continue reading

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My MongoDB cheatsheet

Few years ago, I was working on one mongoDB project.Its a NoSQL database , easy to learn and its pure JSON based. I learned it myself and had created a cheatsheet for it, so I can easily recall it anytime … Continue reading

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Python : Inplace update json and maintain proper order

Some time we have to read one existing json property file and  update some values inplace. If we don’t use proper approach, the update may lead to breaking the json structure in the file. We have to hook the json … Continue reading

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Using optparse in python

Sometimes we have to create tools that takes input as argument with certain options. We can create such tool with optparse module of python. Here is a small example of using this.   For help, type: ( This will display all … Continue reading

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Send mail using Python’s smtplib module

Python has a built in module to send mail to recipient[s] as to,cc,bcc. Here assumption is that : the smtp is configured in localhost (where the script will run).      

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Knife remove all recipes from the run_list

There is a simple knife command which can be used to remove all recipes from the run_list of all nodes in a environment. For this you have to create a dummy role like suppose dummy_role. #knife role create dummy_role Once … Continue reading

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