Kaushik Das Blog

  • MongoDB Collection-Level Access Control

    MongoDB Collection-Level Access Control

    MongoDB has RBAC (Role Based Access Control) enabled that we all know. Different teams having integration with their separate collection, we might have to create collection specific access control by defining userDefine Role. How to create user define role and how to assign user, you can check it from the mongodb documentations. Here in this… Read More »

  • MongoDB change or update field type

    MongoDB change or update field type

    Many a times developer do ask a common question that, we need to change existing data bearing field’s data type to another data type with out hampering existing data. Such as example, in database date field was in string value, but need to convert it in ISODate() format. Before going to nitty gritty details of… Read More »

  • MongoDB export (mongoexport) using aggregation

    MongoDB export (mongoexport) using aggregation

    When we are thinking for exporting data in csv, tsv or json format from MongoDB then probably one tool we are using that is mongoexport. This is pretty straight forward and setting up all parameters will get back your desired data in desired format, but in this article we are talking about some situation which… Read More »

  • MongoDB auto increment field

    This article for those who just jump into MongoDB ocean from RDBMS world. First of all, I can tell you do not start finding stuff which usually support by RDBMS into MongoDB. When you decided to start learning MongoDB then you should be consider yourself as a novice, then you can probable start learning it… Read More »

  • MongoDB Log Rotation Automation

    When you are using mongodb for large applications (heavy write and read intensive), then you probable noticed that mongod.log/mongos.log file is growing big in size with in a few time span. I saw 20GB mongos.log file size in a single day. So, your logfile should be in a limited size for diagnostics and debugging purpose.… Read More »

  • MongoDB performance tuning

    MongoDB performance tuning

    I have faced many projects which are facing performance issue with MongoDB and I do call for tuning up the performance. What I do apparently in a quick succession, that I listed below the steps. Hardware Resource Firstly, quantify already load on the database from mongostat and mongotop. If your are projecting, then try to… Read More »

  • 3. Shell comparison operator & reference

    Command Description Example & Run the previous command in the background ls & && Logical AND if [ “$X” -ge “0” ] && [ “$X” -le “9”] || Logical OR if [ “$X” -lt “0” ] || [ “$X” -gt “9” ] ^ Start of line grep “^X” $ End of line grep “X$” =… Read More »

  • 2. Shell script loop & conditional statement

    Like other programming languages, shell script also have same loop concept, let us look at different types of loop syntax how it will work in shell scripts. For loop While Loops : always define as true, test below example. read is the command take user input, we will learn it later in details. Creating Directory… Read More »

  • Run Shell script in Windows 10

    Yes we can use Woindows 10 for execution of bash script. You need to change following things to make it enabled. After reboot open browser and hit https://aka.ms/wslstore will open store and install ubuntu. Now store a shell file given below to your desktop with .sh file extension. Example : test.sh Then go to terminal… Read More »

  • 1. Shell script comment variable and wildcard

    As we probably all know, shell script is badly required, when you thought to automate something in your operating system. We are here using Born shell(sh) and bash in linux ubuntu. Shell Comments We are making comments placing # symbol at the beginning of line which we need to comment out, or write comment should… Read More »

  • MongoDB 4.4 new features

    MongoDB 4.4 new features

    This version of MongoDB has some path breaking features, few are badly required and most of them has given for enhancement of its features. There are many features, but I am talking about in this article which is more important for performance aspect as well as scalability concern. I am highlighting few new features are… Read More »