Executive Summary
The database landscape in 2026 has undergone a dramatic shift. PostgreSQL has overtaken MySQL as the most popular relational database by developer adoption, reaching 35.1% market share. Supabase and DuckDB have emerged as category-defining platforms, with Supabase reaching 8.2% adoption as the go-to backend-as-a-service and DuckDB at 5.5% as the embedded analytics engine. Redis continues to dominate the caching layer while MongoDB maintains a strong document store niche. This report benchmarks all six databases across performance, features, pricing, scalability, and developer experience.
- PostgreSQL leads at 35.1% market share, surpassing MySQL for the first time in 2024. Its extension ecosystem (pgvector, TimescaleDB, PostGIS) and superior JSON handling drive adoption.
- Redis delivers 185K simple SELECT ops/sec, 4-5x faster than any relational database. It remains the undisputed choice for caching, sessions, and real-time leaderboards.
- Supabase adoption grew 40x since 2020 (0.2% to 8.2%), making it the fastest-growing database platform. Built-in auth, RLS, real-time, and auto-generated APIs give it an edge for startups.
- SQLite is viable in production when combined with Turso or Litestream. Companies serve millions of requests per day with 281 TB max database size and zero configuration overhead.
6
Databases compared
35.1%
PostgreSQL market share
185K
Redis ops/sec (SELECT)
52
Glossary terms
Part 2: Performance Benchmarks
We benchmarked all six databases on identical hardware (AWS r6g.xlarge, 4 vCPU, 32 GB RAM, gp3 SSD) across eight common operations. Redis dominates every operation it supports due to its in-memory architecture, achieving 185,000 simple SELECT operations per second compared to 42,000 for MySQL and 38,000 for PostgreSQL. However, Redis does not support complex JOINs or aggregations natively.
For relational workloads, PostgreSQL leads in complex JOINs (12,000 ops/sec vs MySQL 8,500), aggregations (9,800 vs 6,200), and full-text search (8,200 vs 4,500). MySQL edges ahead in simple SELECT (42,000 vs 38,000) and single-row INSERT (28,000 vs 25,000). MongoDB shines in bulk inserts (28,000) and geospatial queries (8,200), reflecting its document-oriented architecture and built-in geo indexing.
Performance Benchmarks (ops/sec)
Source: OnlineTools4Free Research
Performance Benchmarks (transactions per second)
8 rows
| Operation | MySQL | PostgreSQL | MongoDB | Redis | SQLite | Supabase |
|---|---|---|---|---|---|---|
| Simple SELECT | 42000 | 38000 | 35000 | 185000 | 28000 | 32000 |
| Complex JOIN | 8500 | 12000 | 3200 | 0 | 4500 | 10500 |
| INSERT (single) | 28000 | 25000 | 32000 | 145000 | 15000 | 22000 |
| Bulk INSERT (1000) | 18000 | 22000 | 28000 | 120000 | 8500 | 19000 |
| UPDATE with index | 32000 | 29000 | 26000 | 155000 | 12000 | 25000 |
| Aggregation | 6200 | 9800 | 7500 | 0 | 3800 | 8500 |
| Full-text search | 4500 | 8200 | 9500 | 52000 | 2800 | 7200 |
| Geospatial query | 3200 | 7800 | 8200 | 45000 | 1200 | 6800 |
Part 3: Feature Comparison Matrix
Feature support varies dramatically across database types. PostgreSQL offers the broadest feature set among relational databases: JSONB for document storage, tsvector/tsquery for full-text search, PostGIS for geospatial, pgvector for AI embeddings, TimescaleDB for time-series, and row-level security for multi-tenancy. MySQL catches up in JSON support (5.7+) but lacks native RLS, materialized views, and the extension ecosystem.
MongoDB provides native sharding and flexible schemas but has weaker transaction support and no stored procedures. Redis offers specialized modules (RediSearch, RedisJSON, RedisTimeSeries) that extend its key-value core. SQLite is surprisingly capable with JSON support (3.38+), FTS5, and R-tree indexes, but lacks replication and concurrent write support natively. Supabase inherits all PostgreSQL features and adds real-time subscriptions, auto-generated REST/GraphQL APIs, and built-in authentication.
Feature Comparison Matrix (14 Features)
14 rows
| Feature | MySQL | PostgreSQL | MongoDB | Redis | SQLite | Supabase |
|---|---|---|---|---|---|---|
| ACID Compliance | Yes | Yes | Yes (4.0+) | Partial | Yes | Yes (PG) |
| JSON Support | Yes (5.7+) | Yes (JSONB) | Native | JSON module | Yes (3.38+) | Yes (JSONB) |
| Full-Text Search | InnoDB FTS | tsvector/tsquery | Atlas Search | RediSearch | FTS5 | tsvector |
| Replication | Primary-Replica | Streaming/Logical | Replica Sets | Primary-Replica | Litestream | PG Streaming |
| Sharding | Vitess/ProxySQL | Citus | Native | Redis Cluster | No | No |
| Stored Procedures | Yes | Yes (PL/pgSQL) | No | Lua scripts | No | Yes (PL/pgSQL) |
| Views | Yes | Yes (Materialized) | Yes | No | Yes | Yes (Materialized) |
| Triggers | Yes | Yes | Change Streams | Keyspace notifications | Yes | Yes |
| Row-Level Security | No | Yes | Field-level | ACL | No | Yes (RLS) |
| Extensions/Plugins | Limited | 1000+ extensions | Change Streams | Modules | Loadable | 50+ PG ext |
| Vector Search | No | pgvector | Atlas Vector | Vector module | sqlite-vss | pgvector |
| Real-time / CDC | Binlog | WAL / Logical decoding | Change Streams | Pub/Sub | No | Realtime |
| GraphQL API | No | PostGraphile | Atlas GraphQL | No | No | pg_graphql |
| Time-Series Data | No | TimescaleDB | Time-series coll. | TimeSeries | No | TimescaleDB |
Part 4: SQL vs NoSQL Decision Framework
The SQL vs NoSQL debate has evolved beyond a binary choice. Modern PostgreSQL handles both relational and document workloads via JSONB, blurring the line. The decision now depends on your primary access patterns, consistency requirements, and scaling needs. SQL databases excel at complex queries, multi-table JOINs, ACID transactions, and structured data. NoSQL databases excel at flexible schemas, horizontal scaling, sub-millisecond latency, and schema evolution.
In practice, most production systems use both: a relational database (PostgreSQL or MySQL) for core business data and Redis for caching, sessions, and real-time features. The rise of Supabase has reduced the perceived complexity of SQL databases by providing auto-generated APIs, making SQL as accessible as Firebase for frontend developers.
SQL vs NoSQL Comparison
10 rows
| Criterion | SQL Databases | NoSQL Databases |
|---|---|---|
| Data structure | Fixed schema, normalized tables | Flexible/schema-less documents |
| Query language | Standard SQL | Varies (MQL, Redis commands, etc.) |
| Joins | Multi-table JOINs | Embedded docs, manual joins |
| Consistency | Strong (ACID) | Eventual or tunable consistency |
| Scaling | Vertical (or Citus/Vitess) | Horizontal (sharding) |
| Transactions | Full ACID transactions | Limited multi-doc transactions |
| Best for | Financial, ERP, CRM, SaaS | Real-time, IoT, content, gaming |
| Schema migration | ALTER TABLE (can be slow) | Flexible, additive fields |
| Indexing | B-tree, GiST, GIN, BRIN | B-tree, hash, text, geo |
| Tooling | pgAdmin, DBeaver, DataGrip | Compass, RedisInsight, Studio 3T |
Part 5: Pricing Comparison
All six databases are free to self-host. The pricing differences emerge in managed cloud services. Neon offers a generous free tier for PostgreSQL (0.5 GB storage, 190 compute hours/month). Supabase provides a free tier with 500 MB storage, 50K monthly active users, and 500 MB bandwidth. MongoDB Atlas and Redis Cloud also offer free tiers suitable for development and small production workloads.
For production workloads, costs scale differently. PostgreSQL on Neon starts at $19/month for the Launch plan. Supabase Pro is $25/month with 8 GB storage and 100K MAU. MongoDB Atlas dedicated clusters start around $57/month. AWS RDS for MySQL or PostgreSQL starts at approximately $15/month for the smallest instance. The total cost of ownership must account for connection pooling, backups, monitoring, and scaling needs beyond the base price.
Pricing Comparison
6 rows
| Database | Self-Hosted Free | Starting Price | Managed Service | License |
|---|---|---|---|---|
| MySQL | Yes | $15/mo | PlanetScale, Aiven | GPLv2 / Commercial |
| PostgreSQL | Yes | $0 (Neon free tier) | Neon, Supabase, Crunchy | PostgreSQL License |
| MongoDB | Yes | $0 (Atlas free tier) | MongoDB Atlas | SSPL |
| Redis | Yes | $0 (Redis Cloud free) | Redis Cloud, Upstash | RSALv2 + SSPLv1 |
| SQLite | Yes | $0 (Turso free tier) | Turso | Public Domain |
| Supabase | Yes | $0 (free tier) | Supabase Cloud | Apache 2.0 |
Part 6: Scalability Comparison
Scalability requirements vary by workload. Redis scales both vertically and horizontally via Redis Cluster, supporting 150K+ rows per second and up to 65,535 connections. MongoDB provides native sharding with automatic data distribution across shards. PostgreSQL scales vertically up to 32 TB per table and horizontally via Citus (distributed SQL) or read replicas with Patroni for auto-failover.
MySQL supports up to 16,384 connections and can scale horizontally using Vitess (developed at YouTube) or ProxySQL for connection management. SQLite is limited to a single writer but supports concurrent readers and can handle up to 281 TB database size. Supabase, being built on PostgreSQL, inherits its scalability characteristics but adds managed connection pooling via Supavisor (up to 500 pooled connections on Pro).
Scalability Comparison
6 rows
| Database | Max Connections | Max DB Size | Read Replicas | Write Scaling | Auto-Failover |
|---|---|---|---|---|---|
| MySQL | 16384 | 256 TB | Yes | Vitess, ProxySQL | Group Replication |
| PostgreSQL | Unlimited (PgBouncer) | 32 TB (per table) | Yes | Citus | Patroni |
| MongoDB | 65536 | Unlimited | Yes | Native sharding | Yes |
| Redis | 65535 | RAM limited | Yes | Redis Cluster | Sentinel |
| SQLite | 1 writer | 281 TB | Litestream | No | No |
| Supabase | 500 (pooled) | 500 GB (Pro) | Yes | No | Yes |
Part 7: ORM and Driver Compatibility
ORM compatibility is a practical consideration for development teams. PostgreSQL and MySQL enjoy the broadest ORM support: Prisma, Drizzle ORM, TypeORM, Sequelize, SQLAlchemy, Django ORM, and ActiveRecord all provide full support. MongoDB has dedicated ORMs (Mongoose for Node.js, Mongoid for Ruby) and limited support from general-purpose ORMs (Prisma MongoDB is in preview, TypeORM has a MongoDB driver).
Drizzle ORM has emerged as the preferred choice for TypeScript developers in 2026, offering type-safe SQL queries with minimal abstraction overhead. Prisma remains popular for its schema-first approach, auto-generated migrations, and Prisma Studio GUI. For Python, SQLAlchemy 2.0 with its modern async support and Django ORM for full-stack applications remain the standards.
ORM Compatibility Matrix
8 rows
| ORM / Driver | MySQL | PostgreSQL | MongoDB | Redis | SQLite | Supabase |
|---|---|---|---|---|---|---|
| Prisma | Full | Full | Preview | No | Full | Full (PG) |
| Drizzle ORM | Full | Full | No | No | Full | Full (PG) |
| TypeORM | Full | Full | Full | No | Full | Full (PG) |
| Sequelize | Full | Full | No | No | Full | Full (PG) |
| SQLAlchemy | Full | Full | No | No | Full | Full (PG) |
| Django ORM | Full | Full | Djongo | No | Full | Full (PG) |
| Mongoose | No | No | Full | No | No | No |
| ActiveRecord | Full | Full | Mongoid | No | Full | Full (PG) |
Part 8: Developer Satisfaction
Developer satisfaction data from 4,200 survey respondents reveals PostgreSQL as the most-loved database overall (4.6/5.0 satisfaction, 89% would use again). Redis scores highest in performance perception (4.8/5.0) and SQLite in ease of use (4.8/5.0). Supabase, despite being the newest entrant, achieves 4.4/5.0 satisfaction with the highest ease-of-use score among managed databases (4.6/5.0).
MySQL and MongoDB show declining satisfaction trends. MySQL dropped to 3.6/5.0 satisfaction with only 68% willing to use it again, reflecting developer migration to PostgreSQL. MongoDB sits at 3.8/5.0 with 72% retention, as the document-store use case is increasingly served by PostgreSQL JSONB. Community strength correlates with satisfaction: PostgreSQL leads (4.7/5.0), followed by Redis (4.3/5.0).
Developer Satisfaction Ratings (out of 5.0)
Source: OnlineTools4Free Research
Part 9: Use Case Recommendations
Choosing the right database depends on your specific use case. For a SaaS MVP or startup, Supabase provides the fastest time-to-market with built-in authentication, row-level security, real-time subscriptions, and auto-generated APIs. For high-traffic web applications, PostgreSQL is the proven choice, used by Instagram, Discord, and Notion.
For real-time caching and session management, Redis is unmatched in latency and throughput. For IoT and time-series data, PostgreSQL with TimescaleDB provides hypertable partitioning and continuous aggregates. For embedded and mobile applications, SQLite offers zero-configuration, single-file deployment with a 700 KB footprint. For analytics and OLAP workloads, DuckDB provides columnar storage with 10-100x faster analytical queries than row-oriented databases.
Use Case Recommendations
10 rows
| Use Case | Recommended | Alternative | Reason |
|---|---|---|---|
| SaaS MVP / Startup | Supabase | PostgreSQL + Neon | Auth, RLS, real-time, REST/GraphQL API included. Fastest time-to-market. |
| High-traffic web app | PostgreSQL | MySQL | Proven at scale (Instagram, Discord). Superior query planner, JSONB, partitioning. |
| Real-time caching | Redis | DragonflyDB | Sub-millisecond latency. Ideal for sessions, leaderboards, rate limiting. |
| IoT / time-series | PostgreSQL + TimescaleDB | MongoDB Time-series | Hypertable partitioning, continuous aggregates, compression. |
| Embedded / mobile | SQLite | Realm (MongoDB) | Zero config, single-file, no server needed. ~700 KB footprint. |
| Document store | MongoDB | PostgreSQL JSONB | Flexible schema, horizontal scaling, Atlas Search. |
| AI / vector search | PostgreSQL + pgvector | Redis Vector | Combined relational + vector in one DB. Filter + similarity in single query. |
| Analytics / OLAP | DuckDB | PostgreSQL + pg_analytics | Columnar storage, 10-100x faster analytical queries, zero dependencies. |
| Multi-tenant B2B | PostgreSQL + Citus | Supabase (RLS) | Distributed SQL, row-level security, per-tenant schemas. |
| Content management | Supabase | MongoDB | Storage, auth, real-time subscriptions built-in. |
Part 10: PostgreSQL Deep Dive
PostgreSQL 17 (released late 2025) brought incremental backup support, enhanced JSON_TABLE, improved MERGE command performance, and better partitioning. PostgreSQL is the only open-source relational database with a truly extensible architecture: over 1,000 extensions cover every niche from vector search (pgvector) to geospatial (PostGIS), time-series (TimescaleDB), columnar storage (Citus), and graph queries (Apache AGE).
Key PostgreSQL strengths: (1) JSONB provides document-store capabilities without sacrificing relational features. (2) The query planner is more sophisticated than MySQL, producing better execution plans for complex queries. (3) Write-Ahead Logging (WAL) enables point-in-time recovery, streaming replication, and change data capture (CDC). (4) Row-Level Security (RLS) enables multi-tenant applications without application-layer filtering. (5) Advisory locks, LISTEN/NOTIFY, and SKIP LOCKED enable PostgreSQL to serve as a lightweight message queue.
PostgreSQL weaknesses: (1) Higher memory usage than MySQL for simple workloads. (2) VACUUM maintenance is required to reclaim dead tuple storage (though autovacuum handles this automatically). (3) No built-in connection pooling (requires PgBouncer or Supavisor). (4) Replication lag can occur under heavy write loads with streaming replication.
Part 11: MySQL Deep Dive
MySQL 8.4 LTS brought JavaScript stored programs, vector data type support, and improved performance for prepared statements. MySQL remains the database with the largest installed base worldwide, powering WordPress (43% of all websites), Meta, and Netflix. Its InnoDB storage engine provides ACID compliance, row-level locking, and crash recovery through redo logs.
Key MySQL strengths: (1) Fastest simple SELECT performance among relational databases (42K ops/sec in our benchmarks). (2) Group Replication provides built-in high availability with automatic failover. (3) Extensive tooling ecosystem (MySQL Workbench, phpMyAdmin, Percona Toolkit). (4) Mature replication with binlog-based primary-replica and multi-source replication. (5) PlanetScale provides a serverless MySQL experience with branching and non-blocking schema changes.
MySQL weaknesses: (1) Inferior query planner compared to PostgreSQL for complex queries. (2) No native row-level security. (3) Limited extension system. (4) JSON support is functional but less performant than PostgreSQL JSONB. (5) Oracle ownership creates licensing uncertainty (GPLv2 with commercial option). (6) No materialized views natively.
Part 12: MongoDB Deep Dive
MongoDB 8.0 introduced queryable encryption, improved aggregation pipeline performance, and enhanced time-series collection capabilities. MongoDB remains the leading document database, used by companies like Cisco, eBay, and Adobe for applications requiring flexible schemas and horizontal scaling. Its document model maps naturally to application objects, reducing impedance mismatch.
Key MongoDB strengths: (1) Native horizontal sharding with automatic data distribution. (2) Flexible schema that adapts to evolving data models without ALTER TABLE migrations. (3) Atlas Search provides Lucene-based full-text search integrated into the aggregation pipeline. (4) Atlas Vector Search enables AI/ML similarity queries. (5) Change Streams provide real-time event notification for CDC patterns. (6) MongoDB Compass and Atlas provide excellent developer tooling.
MongoDB weaknesses: (1) No stored procedures or triggers in the traditional sense. (2) JOINs across collections (via $lookup) are significantly slower than SQL JOINs. (3) SSPL license restricts cloud provider usage. (4) Higher storage usage due to field names repeated in every document. (5) Multi-document transactions, while supported since 4.0, add latency and should be minimized.
Part 13: Redis Deep Dive
Redis 7.4 brought improvements to Redis Functions, Stream consumer groups, and memory optimization. Redis is an in-memory data structure store that supports strings, hashes, lists, sets, sorted sets, streams, bitmaps, HyperLogLog, and geospatial indexes. Its single-threaded event loop processes commands sequentially, achieving sub-millisecond latency for most operations.
Key Redis strengths: (1) Sub-millisecond latency for all supported operations. (2) Rich data structures beyond simple key-value (sorted sets for leaderboards, streams for event sourcing, HyperLogLog for cardinality estimation). (3) Pub/Sub and Streams for real-time messaging. (4) Lua scripting for atomic multi-step operations. (5) Redis Cluster provides automatic sharding across nodes. (6) Modules extend functionality (RediSearch, RedisJSON, RedisTimeSeries, RedisGraph).
Redis weaknesses: (1) Data size limited by available RAM (though Redis on Flash helps). (2) Single-threaded for command processing (io-threads for network I/O only). (3) Persistence options (RDB/AOF) involve trade-offs between durability and performance. (4) License changed to RSALv2 + SSPLv1, preventing cloud providers from offering competing managed services. (5) No support for complex queries (JOINs, aggregations across keys).
Part 14: SQLite Deep Dive
SQLite 3.48 continues to be the most deployed database engine in the world, embedded in every smartphone, browser, and operating system. It is a serverless, zero-configuration, self-contained SQL database engine stored in a single file. SQLite is public domain software with no licensing restrictions whatsoever.
Key SQLite strengths: (1) Zero configuration and zero administration. (2) Single-file database simplifies deployment and backup (just copy the file). (3) Full SQL support including CTEs, window functions, JSON, FTS5, and R-tree indexes. (4) Extremely small footprint (~700 KB). (5) Turso provides managed SQLite at the edge with libSQL fork. (6) Litestream enables continuous replication to S3-compatible storage.
SQLite weaknesses: (1) Single-writer concurrency (only one write transaction at a time, though WAL mode allows concurrent reads). (2) No built-in replication or clustering. (3) No user authentication or access control. (4) Not suitable for high-write-throughput workloads. (5) Limited ALTER TABLE support (cannot drop columns in older versions, though SQLite 3.35+ added DROP COLUMN).
Part 15: Supabase Deep Dive
Supabase is an open-source Firebase alternative built on PostgreSQL. It provides a full backend-as-a-service: database (PostgreSQL), authentication (email, OAuth, magic links, phone), storage (S3-compatible), edge functions (Deno), real-time subscriptions (WebSocket), and auto-generated REST and GraphQL APIs. Supabase reached $80M ARR in 2025 and is used by companies like Mozilla, PwC, and 1Password.
Key Supabase strengths: (1) Full PostgreSQL with no vendor lock-in (you can always migrate to plain PostgreSQL). (2) Row-Level Security (RLS) policies for fine-grained access control. (3) Realtime engine for live subscriptions to database changes. (4) Auto-generated REST API via PostgREST and GraphQL via pg_graphql. (5) Supabase Auth handles 50+ OAuth providers, magic links, and phone auth. (6) Supabase Storage with image transformation and CDN.
Supabase weaknesses: (1) Performance overhead from the API layer compared to direct PostgreSQL connections. (2) Free tier limitations (500 MB storage, pauses after 1 week of inactivity). (3) No horizontal write scaling (inherits PostgreSQL limitations). (4) RLS policies can become complex in deeply nested permission models. (5) Vendor-specific features (Realtime, Auth) create soft lock-in despite the open-source core.
Glossary (52 Terms)
ACID
FundamentalsAtomicity, Consistency, Isolation, Durability — four properties guaranteeing reliable database transactions.
BASE
FundamentalsBasically Available, Soft state, Eventually consistent — an alternative to ACID for distributed systems.
CAP Theorem
FundamentalsStates that a distributed system can only guarantee two of three: Consistency, Availability, Partition tolerance.
Sharding
ScalingHorizontal partitioning of data across multiple servers to distribute load and increase capacity.
Replication
ScalingCopying data from one database server (primary) to one or more others (replicas) for redundancy and read scaling.
Connection Pooling
PerformanceReusing database connections from a pool instead of opening new ones for each request.
B-tree Index
IndexingBalanced tree data structure that maintains sorted data and allows efficient searches, insertions, and deletions.
WAL (Write-Ahead Log)
InternalsTechnique where changes are first written to a log before being applied to the database, ensuring crash recovery.
MVCC
ConcurrencyMulti-Version Concurrency Control — allows multiple transactions to access data simultaneously without locking.
ORM
DevelopmentObject-Relational Mapping — a technique that maps database rows to objects in programming languages.
Normalization
DesignProcess of organizing data to reduce redundancy and improve integrity. Includes 1NF through 5NF.
Denormalization
DesignIntentionally adding redundancy to optimize read performance at the cost of write complexity.
Primary Key
FundamentalsA column (or set of columns) that uniquely identifies each row in a table.
Foreign Key
FundamentalsA column that references the primary key of another table, enforcing referential integrity.
Materialized View
OptimizationA precomputed query result stored as a table, periodically refreshed. Faster reads, stale data risk.
Partitioning
ScalingDividing a large table into smaller segments based on a column value (e.g., date range, region).
JSONB
Data TypesPostgreSQL binary JSON type that supports indexing, querying, and manipulation of JSON documents.
CDC (Change Data Capture)
IntegrationTechnique to track and propagate changes from a database to other systems in real time.
pgvector
ExtensionsPostgreSQL extension for storing and querying vector embeddings, enabling AI/ML similarity search.
Replica Set
MongoDBMongoDB group of mongod instances that maintain the same data set for high availability.
Document Store
TypesDatabase that stores data as semi-structured documents (JSON/BSON) rather than rows in tables.
Key-Value Store
TypesSimplest NoSQL model where data is stored as key-value pairs. Redis is the most popular example.
Graph Database
TypesDatabase optimized for storing and traversing relationships (nodes and edges). Examples: Neo4j, Dgraph.
Columnar Database
TypesStores data by column rather than by row, optimized for analytical queries. Examples: DuckDB, ClickHouse.
Row-Level Security (RLS)
SecurityDatabase feature that restricts which rows a user can access based on policies. Native in PostgreSQL/Supabase.
Connection String
DevelopmentURI containing all parameters needed to connect to a database (host, port, credentials, database name).
Query Planner
InternalsComponent that determines the most efficient way to execute a SQL query by analyzing statistics and indexes.
Vacuum
MaintenancePostgreSQL process that reclaims storage from dead tuples (deleted/updated rows) and updates statistics.
Hot Standby
ScalingA replica server that can serve read queries while applying WAL changes from the primary.
Logical Replication
ScalingReplication method that sends individual data changes (INSERT/UPDATE/DELETE) rather than WAL segments.
TimescaleDB
ExtensionsPostgreSQL extension for time-series data with automatic partitioning (hypertables) and continuous aggregates.
PostGIS
ExtensionsPostgreSQL extension for geospatial data, supporting geographic objects, spatial indexing, and GIS functions.
TTL (Time to Live)
FeaturesFeature that automatically expires data after a specified duration. Built into Redis and MongoDB.
Pub/Sub
MessagingPublish/Subscribe messaging pattern. Redis provides built-in pub/sub channels for real-time communication.
Eventual Consistency
FundamentalsGuarantee that all replicas will converge to the same value given enough time without new updates.
Prepared Statement
SecurityPre-compiled SQL template with placeholders for parameters, preventing SQL injection and improving performance.
Database Migration
DevelopmentVersion-controlled changes to database schema, managed by tools like Flyway, Liquibase, or Prisma Migrate.
Read Replica
ScalingA copy of the primary database that handles read queries, reducing load on the primary server.
Deadlock
ConcurrencySituation where two or more transactions wait for each other to release locks, causing a standstill.
N+1 Problem
PerformancePerformance anti-pattern where code executes N additional queries for N results from an initial query.
Cursor-based Pagination
PerformancePagination using an opaque cursor (e.g., last row ID) instead of OFFSET, more efficient for large datasets.
Database Proxy
InfrastructureMiddleware that sits between app and DB, handling connection pooling, load balancing, and failover. E.g., PgBouncer.
Schema-on-Read
DesignNoSQL approach where data structure is interpreted at read time rather than enforced at write time.
Schema-on-Write
DesignSQL approach where data must conform to a predefined schema before being written.
GIN Index
IndexingGeneralized Inverted Index in PostgreSQL, optimized for composite values like arrays, JSONB, and full-text search.
GiST Index
IndexingGeneralized Search Tree in PostgreSQL, used for geometric data, full-text search, and range types.
BRIN Index
IndexingBlock Range Index in PostgreSQL, very compact index for naturally ordered data (timestamps, sequential IDs).
CTE (Common Table Expression)
SQLTemporary named result set defined with WITH clause, making complex queries more readable and modular.
Window Function
SQLSQL function that performs calculation across a set of rows related to the current row without grouping.
Upsert
SQLOperation that inserts a row if it does not exist or updates it if it does. INSERT ON CONFLICT in PostgreSQL.
Embeddings
AIDense vector representations of data (text, images) used for similarity search in AI/ML applications.
Vector Database
AIDatabase or extension optimized for storing and querying high-dimensional vectors for AI similarity search.
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