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Background A Client has E-commerce Application consisting of services aimed at specific domains of business functionality it serves. One of these services is responsible for accepting the order, authenticating it and forwarding it for further processing in terms of inventory checks, payment and so on. For Authentication, this service sends SMS to Customer’s Mobile number (and e-mail id) and customer is supposed to confirm this order placement by means of entering Code received in it. This code is valid for a short duration. ...

Introduction While embarking on building any new server application, one of the key requirement is whether it needs durable, persistent storage of data (and in most cases, it does). This is followed by evaluating suitable data store. Likely evaluation criteria is Application’s Requirement (Tolerance for eventual consistency, High Availability etc.), Team’s familiarity, Costs, Tech. support availability and so on. In case of choices in relational databases, typical go to options are MySQL, PostgreSQL or even proprietary databases like Oracle , SQL Server. Seldom one considers SQLite for this purpose. ...

Introduction We develop a piece of software with aim to fulfil specific business requirements in terms of resource usage, throughput, availability among others. Profiling and benchmarking are approaches that developer has in his/her arsenal to gain continuous feedback on whether a piece of code is behaving optimally and adhering to it’s objectives. Lets look at what they mean, Profiling is defined as process aimed at understanding the behavior of a program. A profile result might be a table of time taken per function, as per this and this) Benchmarking measures the time for some whole operation. e.g. I/O operations per second under some workload. So the result is typically a single number, in either seconds or operations per second. Or a data set with results for different parameters, so you can graph it.. Refer this for more information. Also do check Benchmarking correctly is hard by Julia Evans. Typically, Profiling is supported by most of the environments (either via IDEs like Visual Studio or through language itself [Like Go] has buil-in provision for the same while Benchmarking is typically performed on dedicated testing infrastructure. ...

Introduction I have been reading excellent Database Reliability Engineering book and below are my notes from it. Key Incentive(s) for Automation Elimination of Toil - Toil is the kind of work tied to running a production service that tends to be manual, repetitive, automatable, tactical, devoid of enduring value, and that scales linearly as a service grows. Important System Characteristics Latency, also known as response time, is a time-based measurement indicating how long it takes to receive a response from a request. It is best to measure this for end-to-end response from the customer rather than breaking it down component by component. This is customer-centric design and is crucial for any system that has customers, which is any system ...

Introduction Suppose you have a distributed application running in production and it is based on Micro services/Service Oriented Architecture and have SLA of being “always on” (be available 24*7, barring deployments of course !!). In such cases, having proper monitoring of Application health in place is absolutely essential. What if Monitoring is an afterthought (i.e. application is already in production) ? and that there is little apetite for additional components like (Visualization tools, specialized storage for logs/metrics/traces) for monitoring? ...