Database

A regression in Linux 7.0 has caused PostgreSQL throughput to drop by half on Graviton4 servers due to scheduler preemption changes. Kernel developers suggest PostgreSQL should adopt Restartable Sequences (RSEQ) rather than reverting kernel changes, potentially leading to performance degradation in upcoming Linux 7.0 stable releases, including Ubuntu 26.04 LTS.

Database freezes in a Galera environment were traced to excessive InnoDB history growth caused by AWS Lambda connection pooling. Idle persistent connections kept transactions open, preventing row version purging. Changing the transaction isolation level to READ-COMMITTED resolved the issue by ensuring short-lived read views and allowing consistent garbage collection of undo logs.

This analysis challenges the misconception that frequent database joins are expensive, instead showing they are efficient and scalable. Using DuckDB and PostgreSQL benchmarks, it demonstrates that 'One Big Table' (OBT) models often consume more CPU due to data reassembly and projection costs. Dimensional modeling, as advocated by Ralph Kimball, remains superior for analytical performance.

This table lists various Java Virtual Machine (JVM) configuration flags and options, detailing their names, associated OpenJDK versions, deprecation status, types, operating system compatibility, CPU architectures, components, and primary functional descriptions. These flags are critical for tuning memory management, garbage collection, and Just-In-Time (JIT) compilation performance.

Many applications operate at scales where a formal database is unnecessary. Benchmarking three storage strategies—linear file scans, in-memory maps, and binary search on disk—demonstrates that even simple file-based approaches can handle millions of daily active users. Moving to a database is only essential for complex needs like ACID transactions, multi-field indexing, or distributed writes.

This article demystifies the fifth normal form (5NF) by advocating for a logical design approach rather than traditional, confusing decomposition methods. By starting with business requirements and clear logical models—specifically the AB-BC-AC triangle and the ABC+D star patterns—developers can create fully normalized database schemas without manual splitting or artificial constraints.

pg_textsearch is a high-performance PostgreSQL extension providing BM25 ranking for text search. It features simple syntax, Block-Max WAND optimization for fast top-k queries, and parallel index builds. Designed for production, it supports PostgreSQL 17-18, partitioning, and configurable ranking parameters, making it a scalable alternative for textual information retrieval within the database.

Running a Rails 8 e-commerce site on SQLite offers simplicity but risks data loss during rapid deployments. Using shared Docker volumes with overlapping containers caused write contention, leading to lost transactions. Success requires disciplined deployment intervals, awareness of filesystem-level locking, and utilizing tools like sqlite_sequence for auditing. SQLite remains effective for single-server, read-heavy workloads within these limitations.

This article demonstrates how to render and play a chess game using only SQL. By utilizing a table to store piece positions, conditional aggregation to pivot data into an 8x8 grid, and basic CRUD operations to execute turns, the author shows that SQL is capable of complex game visualization and logic without frontend frameworks or JavaScript.

Torsten Grust provides comprehensive course materials on the internal architecture of DuckDB. The 'DiDi' course, designed for undergraduate students at the University of Tübingen, covers 15 weeks of topics including memory management, vectorized query execution, indexing with ART, and query optimization, providing a deep dive into the kernel of the DuckDB relational database system.

OpenDuck is an open-source project providing a self-hosted implementation of MotherDuck's architecture. It enables differential storage, hybrid execution, and transparent remote database access for DuckDB. By using an open gRPC protocol and Arrow IPC, it allows users to build custom backends that integrate natively with DuckDB's optimizer and catalog.

Ghost provides instant, ephemeral Postgres databases for AI agents, enabling branching, forking, and isolation. It integrates seamlessly with a suite of Postgres-native tools—Memory Engine, TigerFS, and Ox—to provide persistent memory, file storage, and sandboxed execution without requiring complex middleware. This infrastructure simplifies agent workflows by treating databases as disposable, version-controlled project resources.

Modern SQLite provides powerful features like native JSON support, FTS5 for full-text search, window functions for analytics, and STRICT tables for schema enforcement. With generated columns, Write-Ahead Logging (WAL) for concurrency, and CTEs, SQLite has evolved into a robust, high-performance database suitable for complex applications without sacrificing its characteristic simplicity and reliability.

CTEs in PostgreSQL have evolved from 'optimization fences' into an efficient tool. Since PostgreSQL 12, the planner automatically inlines most CTEs unless they are recursive, have side effects, or are referenced multiple times. While materialization can be useful for performance or atomicity, it often hides statistics from the query planner, occasionally leading to inefficient execution plans.

Postgres uses a separate, unencrypted connection for CancelRequest messages sent during query termination. This creates security risks, including potential Denial-of-Service attacks via traffic interception. While Postgres 17 introduced TLS support for these requests, psql has not yet implemented them, highlighting the need for vigilance and secure configuration when managing database traffic and proxy tools.

turbolite is an experimental SQLite VFS in Rust that optimizes database access from S3-compatible cloud storage. It achieves sub-250ms cold start latency using B-tree introspection, page-level zstd-compression, and AES-256-GCM encryption. It utilizes configurable prefetching and a manifest-based architecture to minimize S3 request counts and maximize throughput for tenant-specific application workloads.

This comparison table details the feature differences between two database management tools for PostgreSQL. It covers key functional areas including connection management, schema browsing, table inspection, data management, SQL editing, and file exploration, highlighting specific capabilities unique to each application's implementation.

SQLite 3.53.0 introduces the Query Result Formatter (QRF) library to enhance CLI output, adds support for modifying constraints in ALTER TABLE, improves the query planner, and introduces new JSON functions. It also provides new C APIs and optimizations while addressing critical reliability fixes like the WAL-reset corruption bug.

A RocksDB unit test revealed a high-severity hardware bug in specific newer CPUs. The issue caused the RDSEED instruction to intermittently return incorrect values under high memory load, leading to duplicate identifiers. The discovery highlights the importance of implementing rigorous sanity checks, redundancy, and verifying external dependencies at the architectural level.