databases

Manticore Search 27.1.5 has been released. This release brings built-in authentication and authorization, sharded tables, conversational search, faster HNSW builds, better faceting and aggregations, and a long list of fixes across KNN, replication, protocol compatibility and other areas. This post is a catch-up for everything shipped from 25.0.1 through 27.1.5 . Upgrade Notes Please review these …

1. Introduction Django's ORM is one of its greatest strengths. It abstracts away raw SQL, lets you express database operations in clean Python, and gets you productive fast. But that convenience comes with a hidden cost: if you're not deliberate about how you fetch related objects, you'll silently generate far more queries than you intend — and you won't notice until your app slows to a crawl in …

The Only DBMS & SQL Cheat Sheet You Need for Tech Interviews in 2026 Whether you're a CS student preparing for campus placements or a working professional switching to a product company — DBMS and SQL questions will show up in your interview. Every time. The problem? Most resources are either 500-page textbooks or scattered blog posts that take hours to piece together. This article covers every D…

Introduction To master Power BI, you need to understand how data is structured, connected, and stored. Here is a comprehensive, structured guide to Modelling, Joins, Relationships , and Schemas in Power BI. Data Modeling in Power BI Data modeling is the process of identifying, organizing and defining the types of data a business collects and the relationships between them. It uses diagrams, symbo…

We opened Chapter 1 with a single line, SELECT * FROM users WHERE id = 1 . For that line to leave the client and come back as a result row, the PostgreSQL backend went through five stages. First it decided which processing path the message should take; then the parser and analyzer turned the text into a tree and gave it meaning from the catalog. The rewriter expanded views and injected policies t…

A scan node sits at the leaf of the tree and pulls rows from a single table. A join node sits in the middle and brings together the rows that its two children send up. It takes one row from users , one row from orders , checks whether they belong to the same user, and if they match, emits the combined row. PostgreSQL has three nodes for this one job: NestLoop, HashJoin, and MergeJoin. The reason …

By the time 1.4 ends, the planner has produced one PlannedStmt. Inside it is an execution tree built from Plan nodes, frozen into a form you can follow step by step, something like "go into the primary key index on users, fetch the one matching row, then output that whole row." But that is still only a blueprint. Reading actual pages off disk, picking out the rows that match the condition, handin…

In the earlier posts of this series, we looked at practical query tuning tips and how to read and interpret query plans . A recurring theme in both was: "add an index here." But "add an index" is a bit like saying "use the right tool" — the interesting part is which one. PostgreSQL ships with several index types, each tuned for a different kind of data and query. Picking the wrong one means Postg…

A ~6 minute read — just three concepts that, once you know them, change how you reason about DNS inside a cluster. While chasing some DNS timeouts recently, I went down a rabbit hole and came out with three concepts I wish I'd known earlier. None of them is exotic, but together they explain a surprising amount of "why is DNS being weird" behaviour on Kubernetes-on-AWS. ndots — why one hostname lo…

Your Serverless Is Lying To You About Scale! Introduction The promise of serverless computing is irresistible: infinite scalability, pay-per-use, and zero operational overhead. We've eagerly embraced platforms like AWS Lambda, Google Cloud Run, and Azure Container Apps, pushing them to scale horizontally with unprecedented agility. Yet, a recent surge in backend outages tells a different story. T…

Someone sends you a CSV. Then a folder of CSVs. Then a CSV that's actually tab-separated but named .csv , with a stray header row and a column that's a number on most rows and the string N/A on the rest. For years my answer to "can you pull a quick number out of this?" was a throwaway Python script. Read it in, fight pandas about dtypes, groupby , print, delete the script, forget everything, repe…

DNS Is an Indirection Layer, Not a Lookup Table The "phonebook" metaphor everyone reaches for is actively misleading — and worse, it frames DNS as solved infrastructure when it's anything but. A phonebook is a static mapping. You look up a name, you get a number, done. DNS is something fundamentally different: a decoupling mechanism that separates stable human-readable identifiers from the volati…

What i was learning Today i started learning PostgreSQL , the objective was to create a mental model to build a strong foundation and potentially a smooth learning curve for PostgreSQL . What confused me Coming from SQLite, confusion was inevitable.The initial assumption was that PostgreSQL would be smooth, that perhaps all i needed to do was change the app configuration from SQLite to PostgreSQL…

Originally published on lavkesh.com I've hit walls with traditional SQL databases while building web applications. Evolving schemas become nightmarish migration scripts, and unstructured data doesn't fit neatly into rows and columns. That's where NoSQL databases come in - they don't replace SQL but solve specific problems. The term 'NoSQL' stands for 'Not Only SQL,' which is a vague name. It cove…

Data Modeling, Joins, Relationships, and Different Schemas Introduction In today's data-driven world, organizations generate massive amounts of data from various sources such as websites, mobile applications, financial systems, customer transactions, and social media platforms. To transform this raw data into meaningful information, organizations rely on effective data management techniques. Data…

DuckDB 1.4.5 LTS, pgEdge ColdFront Beta, and SQLite's FCNTL_PDB Internals Today's Highlights This week's highlights feature the latest DuckDB 1.4.5 LTS release, a new open-source beta for PostgreSQL data tiering, and a deep dive into an obscure SQLite internal file control operation. These updates offer performance, architectural flexibility, and internal insights across the SQLite ecosystem. Ann…

Honestly, sometimes migrating between databases during a project is difficult. For example, transferring tables between relational databases or transferring data between a relational database and a NoSQL database. That's why I built Py-Auto-Migrate . What is Py-Auto-Migrate? Py-Auto-Migrate is an open source tool that automatically transfers data between different database systems. Simply provide…

LATERAL joins let a subquery in the FROM clause reference columns from earlier in the same FROM clause. Semi joins return rows where a match exists in another table, without duplicating those rows. Anti joins return rows where no match exists.

Why AI Agents Make Me Reach for SQLite Takafumi Endo Takafumi Endo Takafumi Endo Follow Jun 17 Why AI Agents Make Me Reach for SQLite # sqlite # database # ai # architecture 3 reactions 2 comments 10 min read

PostgreSQL Error 22036: non numeric sql json item PostgreSQL error code 22036 ( non numeric sql json item ) occurs when a SQL/JSON path expression attempts to perform a numeric operation on a JSON item that is not a number — such as a string, boolean, array, or object. This error was introduced alongside the SQL/JSON Path feature in PostgreSQL 12 and typically surfaces in queries using jsonb_path…