PostgreSQL Performance Glossary
Each term now has a dedicated page with metadata, context, and practical benchmarking notes.
A
ACID
ACID ensures reliable processing of database transactions through Atomicity, Consistency, Isolation, and Durability. PostgreSQL adheres strictly to ACID compliance for high data integrity.
Archiving
Archiving in PostgreSQL refers to saving WAL (Write-Ahead Log) files for long-term storage or backup. It's essential for point-in-time recovery and ensuring that no data is lost between backups. Archive mode must be enabled in the config.
Autovacuum
PostgreSQL's background daemon that removes dead tuples and updates statistics automatically. This helps prevent table bloat and ensures consistent query performance.
B
Background Writer
The background writer is a PostgreSQL process that periodically writes dirty buffers from shared memory to disk. This helps spread out I/O and reduce latency during heavy write operations. Monitoring it helps optimize checkpoint performance.
Bloat
Unused space in PostgreSQL tables or indexes caused by frequent updates or deletes. If unmanaged, bloat can slow performance and inflate storage needs.
Branch Preview Database
A branch preview database is an isolated PostgreSQL environment created from a source branch to validate schema changes, migrations, and query behavior before production rollout.
BRIN Index
Block Range Index summarizes data blocks and is highly space-efficient. Best suited for large, naturally ordered datasets like logs or timestamps.
Buffer Pool
A memory area that caches disk pages to reduce I/O. Controlled by shared_buffers , it's key to PostgreSQL performance.
C
Checkpoint
A checkpoint writes all dirty pages from memory to disk and records a log point for recovery. PostgreSQL performs checkpoints periodically or when triggered.
Collation
Collation determines how string values are sorted and compared. PostgreSQL supports multiple collations depending on locale settings.
Connection Pooling
Connection pooling reduces the overhead of frequent database connections by reusing existing ones. Tools like PgBouncer and Pgpool-II provide efficient pooling for PostgreSQL. This improves performance and scalability under high traffic.
CTE (Common Table Expression)
CTEs are temporary named result sets defined using the WITH clause. They make complex queries easier to read and support recursion in PostgreSQL.
D
Data Directory
The data directory is the root folder where PostgreSQL stores its data files, including WAL, configuration, and user data. It’s initialized using initdb and must be secured and monitored.
Database Branching
Database branching is a workflow where teams create isolated database branches from a common baseline to test schema and data changes without impacting shared environments.
Database Cloning
Database cloning creates a copy of a PostgreSQL dataset for testing, analytics, or migration rehearsal, preserving schema and data state at a known point in time.
Dead Tuple
Dead tuples are outdated row versions left after DELETEs or UPDATEs. Autovacuum removes them to free space and maintain performance.
Domain
A domain is a custom data type with constraints like CHECK. It allows for reusability and consistent data validation.
E
Epoch
The epoch is the reference point for Unix time, starting at midnight UTC on January 1, 1970. PostgreSQL can convert timestamps to and from epoch time for easier time calculations. It's useful for working with APIs or time-based math.
Extension
An extension is a package that adds features to PostgreSQL without modifying core code. Examples include PostGIS, pg_stat_statements, and hstore. They are installed using CREATE EXTENSION and can dramatically expand PostgreSQL capabilities.
F
FILLFACTOR
FILLFACTOR determines how much of a data page PostgreSQL fills initially. A lower value leaves more space for updates, reducing page splits and maintaining performance. It's useful for update-heavy tables.
Foreign Key
A foreign key enforces a relationship between two tables to maintain referential integrity. PostgreSQL ensures the referenced row exists before allowing inserts or updates. It's a cornerstone of relational database design.
G
GIN Index
GIN (Generalized Inverted Index) is used for indexing array values, JSONB, and full-text search. It supports fast retrieval for elements within composite data. GIN trades slower writes for quicker queries.
GUC (Grand Unified Configuration)
GUC is the internal name for PostgreSQL configuration parameters. These include runtime options like work_mem and shared_buffers . You can set GUCs in postgresql.conf or via SQL.
M
Materialized View
A materialized view stores the result of a query physically on disk. It can be refreshed periodically and speeds up repeated access to complex joins or aggregations. Unlike regular views, they don’t update in real-time.
MVCC (Multi-Version Concurrency Control)
MVCC allows PostgreSQL to handle multiple transactions simultaneously without locking rows. It achieves this by maintaining different versions of the same data. This ensures consistent reads and high performance under concurrent workloads.
P
Partitioning
Partitioning splits large tables into smaller pieces called partitions. PostgreSQL supports declarative partitioning since version 10, improving performance and manageability for big data sets.
pg_stat_statements
This extension tracks execution statistics of all SQL queries in a PostgreSQL instance. It helps identify slow, frequent, or inefficient queries. Ideal for performance tuning and observability.
pgbench
pgbench is PostgreSQL's built-in tool for benchmarking and performance testing. It simulates concurrent users executing transactions and reports key metrics like TPS and latency. It supports standard and custom SQL scripts for workload simulation.
PITR (Point-In-Time Recovery)
Point-in-time recovery (PITR) restores a PostgreSQL database to an exact timestamp by replaying WAL records from a base backup.
Planner
The planner is PostgreSQL’s component that determines the most efficient way to execute SQL queries. It evaluates possible paths based on cost, statistics, and index availability. It's essential for understanding and tuning query performance.
R
Replication
Replication copies data from one PostgreSQL server (primary) to others (replicas). PostgreSQL supports streaming and logical replication. It's essential for high availability and read scaling.
Restore Point
A restore point is a named marker in PostgreSQL WAL history used to simplify recovery targets when performing point-in-time recovery.
S
Shared Buffers
Shared buffers are PostgreSQL’s internal memory cache for storing frequently accessed disk blocks. The shared_buffers parameter determines its size and is critical for tuning performance.
Simplyblock
Simplyblock is a high-performance block storage platform built for modern cloud-native environments. It provides elastic, low-latency storage that can scale instantly while maintaining enterprise-grade resiliency. Designed for Kubernetes and serverless workloads, Simplyblock separates storage and compute, enabling developers to run data-intensive applications with maximum efficiency and flexibility.
T
Tablespace
A tablespace in PostgreSQL is a directory on disk where database objects like tables and indexes are stored. It allows for spreading data across multiple disks for performance or storage control.
TPS (Transactions Per Second)
TPS is a metric indicating how many transactions a PostgreSQL database processes per second. It's commonly used to benchmark and evaluate system throughput under load. Higher TPS suggests better database performance under concurrent access.
Tuple
A tuple is PostgreSQL's internal term for a row in a table. Multiple versions of a tuple may exist due to MVCC, especially during updates or deletes. Tuples are reclaimed through VACUUM operations to prevent storage bloat.
V
VACUUM
VACUUM reclaims storage occupied by dead tuples in PostgreSQL. It keeps tables from bloating and improves performance. There’s also VACUUM FULL for more aggressive cleanup.
Vela Postgres
Vela Postgres is an enterprise Postgres development platform with instant cloning, git-like branching, and workflow tooling for fast iteration. It adds operational features such as RBAC, live migration support, and separation of storage and compute.