Database Administration

What is Connection Pooling?

Connection pooling is a technique where a fixed set of pre-established database connections is reused across multiple requests instead of opening and closing a…

Full vs Incremental Database Backups: What is the Difference?

A full backup copies every byte of the database at a point in time, while an incremental backup copies only the data that changed since the last backup of any…

What is Point-in-Time Recovery (PITR)?

Point-in-time recovery restores a database to its exact state at a specific past moment by combining a full backup with the replay of transaction logs up to th…

Why is Restore Testing Important for Database Backups?

Restore testing is the practice of regularly restoring a backup to a separate environment and verifying the data is complete and usable, because a backup that…

What are RPO and RTO in Database Disaster Recovery?

RPO (Recovery Point Objective) is the maximum acceptable amount of data loss measured in time, such as losing at most 15 minutes of writes, while RTO (Recovery…

Hot Backup vs Cold Backup: What is the Difference?

A hot backup is taken while the database stays online and serving reads and writes, using transaction-consistent snapshots or log coordination, whereas a cold…

What is a Reliable Methodology for Tuning a Slow SQL Query?

A reliable query-tuning methodology starts with measuring, not guessing: capture the query's actual execution plan, identify the single most expensive operatio…

How Do You Analyze a Slow Query Log to Find Optimization Targets?

Analyzing a slow query log means aggregating logged queries by their normalized pattern and ranking them by total cumulative time, not by the single slowest in…

What is Role-Based Access Control (RBAC) in Database Security?

Role-Based Access Control (RBAC) is a database security model where permissions are granted to named roles rather than to individual users, and users gain thei…

How Do You Implement Row-Level Security in a Database?

Row-level security (RLS) is implemented by attaching a security policy to a table that filters which individual rows a given user or role can see or modify, en…

What is Data Encryption at Rest in a Database?

Data encryption at rest means the data stored on disk — table files, indexes, backups, and logs — is encrypted so that anyone who gains raw access to the stora…

What is Data Encryption in Transit for Databases?

Data encryption in transit protects data while it moves across a network — between an application and the database, between replicas, or during a backup transf…

What is Database Auditing and Compliance Logging?

Database auditing and compliance logging is the practice of recording who accessed or modified which data, when, and how, in a tamper-resistant log, so an orga…

What is Database Connection Multiplexing?

Database connection multiplexing is the technique of sharing a small pool of real database connections across a much larger number of client requests, typicall…

How Do You Safely Run Database Migrations in a CI/CD Pipeline?

Safe database migrations in CI/CD rely on the expand-contract pattern: first deploy a backward-compatible schema change that both old and new application code…