Posts (page 222)
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6 min readTo implement custom aggregate functions in PostgreSQL, you can follow these steps:Define the aggregate function: Start by creating a new function using the CREATE FUNCTION statement. Specify the function name, input parameters, return type, and any other required details. Use the AGGREGATE keyword to indicate that it is an aggregate function. Define the state variables: A custom aggregate function often requires state variables to track the intermediate results during aggregation.
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6 min readHigher-order functions are an essential feature of the functional programming language Haskell. A higher-order function is a function that can take other functions as arguments or return functions as results. This allows for flexibility and abstraction in coding.To use higher-order functions in Haskell, you can follow these steps:Define a higher-order function: Start by defining a function that takes one or more functions as arguments or returns a function.
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8 min readTo install Zabbix server on a VPS (Virtual Private Server), follow these steps:Connect to your VPS: Use SSH (Secure Shell) or any other remote access method to connect to your VPS using a terminal. Update the system: Before installing any software, update your VPS to ensure it has the latest packages. Run the following command: sudo apt update && sudo apt upgrade Install necessary dependencies: Zabbix server requires some dependencies to be installed.
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11 min readConnection pooling is a technique used to manage a pool of established database connections. It helps in improving the performance and scalability of applications that require frequent database access, such as web applications.To implement connection pooling for PostgreSQL, you can follow these general steps:Choose a connection pooling library: Various libraries are available that provide connection pooling functionality for PostgreSQL.
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7 min readIn Haskell, writing a recursive function involves defining a function that calls itself within its body. This recursive call allows the function to repeatedly execute its logic until a specified condition is met.To write a recursive function in Haskell, follow these steps:Determine the base case(s): Start by identifying the simplest or trivial inputs for which the function can produce an immediate result without further recursion. These base cases will terminate the recursion.
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8 min readPostgreSQL Query Rewriter is a component within the PostgreSQL database that is responsible for optimizing queries to improve their performance. It works by analyzing the query and applying various optimization techniques to rewrite and rearrange the query execution plan.When a query is submitted to PostgreSQL, the Query Rewriter takes over and performs several operations to optimize it. It starts by analyzing the query to identify potential optimization opportunities.
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7 min readIn Haskell, you can define and use custom data types to create your own data structures with different characteristics. These data types can encapsulate multiple values and provide a way to model your problem domain more accurately. Here's how you can define and use custom data types in Haskell:Defining a Custom Data Type:Use the data keyword to start defining a new data type.Provide a name for your data type, followed by its constructors (possible values).
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10 min readGrafana can be deployed in various environments depending on your needs. Here are some common places you can deploy Grafana:On-premises servers: You can install Grafana on your own servers or virtual machines within your data center or private cloud. This gives you full control over the hardware and network infrastructure, making it suitable for organizations with specific security or compliance requirements.
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6 min readJSONPath is a query language used to extract or search data from JSON documents. PostgreSQL has built-in support for JSON data types, and you can work with JSONPath expressions in queries to retrieve specific data.To work with JSONPath expressions in PostgreSQL queries, you can use the jsonb_path_query function or the @> operator.
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6 min readType annotations in Haskell are used to provide explicit information about the types of variables, functions, and expressions. They are not required by the compiler, but can be specified to add clarity and aid in debugging.To use type annotations in Haskell, the :: symbol is used to separate the name of an entity from its type.
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9 min readConcurrency and isolation levels are essential aspects of managing transactions in PostgreSQL. Concurrency refers to multiple transactions executing simultaneously in the database, while isolation levels determine the level of isolation between these concurrent transactions.To handle concurrency and isolation levels effectively in PostgreSQL transactions, consider the following points:Concurrency Control: PostgreSQL uses a multi-version concurrency control (MVCC) approach to handle concurrency.
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7 min readA list in Haskell is a collection or sequence of elements of the same type. It can be used to store and manipulate multiple values. Lists are particularly useful in functional programming as they enable recursion and pattern matching.To create a list in Haskell, you can use square brackets. Elements are separated by commas. For example, the list of integers [1, 2, 3, 4] contains four elements.Lists can be created using a range of values. You can specify a range using two dots '..