Amazon RDS PostgreSQL Extensions Reference

aws_rds_postgresql_extensions_reference_table.md

Amazon RDS PostgreSQL Extensions Reference

Source AWS extension compatibility matrix:

• AWS RDS PostgreSQL Extensions Matrix
• AWS PostgreSQL Extension Support Docs

Notes:

• "Extension" is the PostgreSQL extension identifier used in CREATE EXTENSION.
• "Canonical Link" points to the upstream project, PostgreSQL docs, or authoritative source.
• Some extensions are AWS-specific and therefore point to AWS documentation.
• Drawbacks are intentionally practical and production-focused.

Extension	Name	Description	Good For	Limitations / Drawbacks	Canonical Link
aws_commons	AWS Common Utilities	Shared helper functions/types for AWS-integrated extensions	Required dependency for aws_s3/aws_lambda	AWS-only, limited outside RDS ecosystem	https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/PostgreSQL.Concepts.General.FeatureSupport.Extensions.html
aws_lambda	AWS Lambda Integration	Invoke AWS Lambda functions directly from PostgreSQL	Event-driven workflows, async jobs, integrations	Network latency, operational coupling, IAM complexity	https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/PostgreSQL-Lambda.html
aws_s3	AWS S3 Integration	Import/export data between PostgreSQL and S3	Bulk exports/imports, analytics pipelines	Tightly coupled to AWS IAM/S3 permissions	https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_PostgreSQL.S3Import.html
bloom	Bloom Index Access Method	Space-efficient probabilistic index	Multi-column filtering at lower storage cost	False positives possible	https://www.postgresql.org/docs/current/bloom.html
btree_gin	B-Tree GIN Operator Classes	B-tree behavior for GIN indexes	Mixed indexing strategies	Larger indexes than standard B-tree	https://www.postgresql.org/docs/current/btree-gin.html
btree_gist	B-Tree GiST Operator Classes	B-tree equivalent support for GiST	Exclusion constraints, mixed GiST usage	Slower than standard B-tree in many cases	https://www.postgresql.org/docs/current/btree-gist.html
chkpass	Encrypted Password Type	Data type for encrypted passwords	Legacy password storage	Obsolete for modern auth systems	https://www.postgresql.org/docs/current/chkpass.html
citext	Case-Insensitive Text	Text type with case-insensitive comparisons	Emails, usernames, normalized search	Locale/collation edge cases	https://www.postgresql.org/docs/current/citext.html
cube	Cube Data Type	Multi-dimensional cube data type	Vector-like geometric calculations	Not a substitute for pgvector	https://www.postgresql.org/docs/current/cube.html
dblink	Database Link	Query remote PostgreSQL databases	Lightweight federation	Hard to secure/manage at scale	https://www.postgresql.org/docs/current/dblink.html
dict_int	Integer Dictionary	Full-text search dictionary for integers	Numeric token indexing	Niche usage	https://www.postgresql.org/docs/current/dict-int.html
dict_xsyn	Extended Synonym Dictionary	Synonym support for text search	Search normalization	Requires careful synonym maintenance	https://www.postgresql.org/docs/current/dict-xsyn.html
earthdistance	Earth Distance	Geographic distance calculations	Radius/location queries	Simpler than PostGIS, less accurate/flexible	https://www.postgresql.org/docs/current/earthdistance.html
flow_control	Flow Control Functions	Utility flow-control helpers	Procedural workflows	Limited practical usage	https://www.postgresql.org/docs/current/contrib-spi.html
hll	HyperLogLog	Probabilistic cardinality estimation	Fast approximate COUNT(DISTINCT)	Approximate only	https://github.com/citusdata/postgresql-hll
hstore	Key-Value Store	Key/value data type	Semi-structured metadata	Inferior to JSONB for most new systems	https://www.postgresql.org/docs/current/hstore.html
hypopg	Hypothetical Indexes	Simulate indexes without creating them	Query optimization/testing	Planner estimates only, not actual execution	https://github.com/HypoPG/hypopg
insert_username	Insert Username Trigger	Trigger inserts current username	Auditing	Very limited functionality	https://www.postgresql.org/docs/current/contrib-spi.html
intagg	Integer Aggregator	Integer aggregation helpers	Specialized aggregation workloads	Rarely needed in modern PG	https://www.postgresql.org/docs/current/intagg.html
intarray	Integer Array Utilities	Functions/operators for integer arrays	Analytics, tagging systems	Limited to integer arrays	https://www.postgresql.org/docs/current/intarray.html
ip4r	IPv4/IPv6 Range Types	IP range indexing/operators	Networking/security systems	More niche than inet/cidr built-ins	https://github.com/RhodiumToad/ip4r
isn	International Standard Numbers	ISBN/ISSN/UPC validation	Publishing/retail systems	Very domain specific	https://www.postgresql.org/docs/current/isn.html
lo	Large Object Support	Manage PostgreSQL large objects	Large binary storage	Operational overhead, vacuum complexity	https://www.postgresql.org/docs/current/lo.html
log_fdw	Log Foreign Data Wrapper	Query PostgreSQL log files	Operational troubleshooting	Read-only and operationally niche	https://www.postgresql.org/docs/current/logfdw.html
ltree	Label Trees	Hierarchical tree structures	Taxonomies, category trees	Specialized query syntax	https://www.postgresql.org/docs/current/ltree.html
moddatetime	Modification Timestamp Trigger	Auto-update modification timestamps	Audit columns	Very limited scope	https://www.postgresql.org/docs/current/contrib-spi.html
mysql_fdw	MySQL Foreign Data Wrapper	Query MySQL from PostgreSQL	Migrations, federated queries	Cross-engine performance issues	https://github.com/EnterpriseDB/mysql_fdw
pg_buffercache	Buffer Cache Inspection	Inspect shared buffer cache	Performance tuning	Read-only diagnostics	https://www.postgresql.org/docs/current/pgbuffercache.html
pg_cron	PostgreSQL Cron Scheduler	Run scheduled jobs inside PostgreSQL	Maintenance jobs, scheduled tasks	Jobs tied to DB lifecycle	https://github.com/citusdata/pg_cron
pg_freespacemap	Free Space Inspection	Inspect table free space map	Storage diagnostics	Operational diagnostics only	https://www.postgresql.org/docs/current/pgfreespacemap.html
pg_hint_plan	Query Planner Hints	Override planner decisions with hints	Performance tuning edge cases	Can hide root-cause query issues	https://github.com/ossc-db/pg_hint_plan
pg_partman	Partition Management	Automated partition management	Time-series/event data	Adds operational complexity	https://github.com/pgpartman/pg_partman
pg_prewarm	Prewarm Shared Buffers	Load relation data into cache	Reduce cold-start latency	Consumes memory aggressively	https://www.postgresql.org/docs/current/pgprewarm.html
pg_similarity	Similarity Functions	Text similarity operations	Search/fuzzy matching	Less common than pg_trgm	https://github.com/eulerto/pg_similarity
pg_stat_statements	Query Statistics Collector	Tracks execution statistics	Query optimization, observability	Adds small execution overhead	https://www.postgresql.org/docs/current/pgstatstatements.html
pg_transport	Data Transport Utilities	Transport/streaming helpers	Migration tooling	AWS/RDS niche usage	https://github.com/aws/pg_transport
pg_trgm	Trigram Matching	Similarity and fuzzy text search	Search/autocomplete	Indexes can become large	https://www.postgresql.org/docs/current/pgtrgm.html
pg_visibility	Visibility Map Inspection	Inspect tuple/page visibility	Vacuum troubleshooting	Diagnostic-only extension	https://www.postgresql.org/docs/current/pgvisibility.html
pgAudit	PostgreSQL Auditing	Detailed audit logging	Compliance/security	High logging overhead possible	https://github.com/pgaudit/pgaudit
pglogical	Logical Replication System	Advanced logical replication	Multi-region replication, migrations	Operationally complex	https://github.com/2ndQuadrant/pglogical
pgrowlocks	Row Lock Inspection	Inspect row-level locks	Concurrency debugging	Diagnostic only	https://www.postgresql.org/docs/current/pgrowlocks.html
pgstattuple	Tuple Statistics	Table/index bloat statistics	Storage optimization	Expensive on large relations	https://www.postgresql.org/docs/current/pgstattuple.html
pgvector	Vector Similarity Search	Embeddings/vector search support	AI semantic search/RAG	Memory intensive at scale	https://github.com/pgvector/pgvector
plcoffee	CoffeeScript Language	CoffeeScript procedural language	Experimental stored procedures	Very niche, mostly obsolete	https://github.com/plv8/plcoffee
plls	LiveScript Language	LiveScript procedural language	Experimental scripting	Rarely used in production	https://github.com/plv8/plls
plperl	Perl Procedural Language	Write functions in Perl	Legacy Perl ecosystems	Security/maintainability concerns	https://www.postgresql.org/docs/current/plperl.html
plpgsql	PostgreSQL Procedural Language	Default procedural language	Stored procedures/triggers	Can become difficult to maintain	https://www.postgresql.org/docs/current/plpgsql.html
plprofiler	PL/pgSQL Profiler	Profile PL/pgSQL execution	Procedure optimization	Profiling overhead	https://github.com/bigsql/plprofiler
pltcl	Tcl Procedural Language	Write functions in Tcl	Legacy Tcl systems	Rarely used today	https://www.postgresql.org/docs/current/pltcl.html
postgis	Spatial GIS Extension	GIS/spatial capabilities	Maps, geospatial systems	Complex and resource intensive	https://postgis.net/
postgis_raster	Raster GIS Support	Raster geospatial processing	Satellite imagery/rasters	Heavy storage/CPU usage	https://postgis.net/docs/RT_reference.html
postgis_tiger_geocoder	TIGER Geocoder	US address geocoding	Address normalization/geocoding	US-centric datasets	https://postgis.net/docs/Extras.html
postgis_topology	GIS Topology	Spatial topology modeling	Advanced GIS systems	Significant complexity	https://postgis.net/docs/Topology.html
postgres_fdw	PostgreSQL FDW	Query remote PostgreSQL servers	Federated Postgres systems	Network latency/performance issues	https://www.postgresql.org/docs/current/postgres-fdw.html
prefix	Prefix Search Operators	Efficient prefix text searching	Search/autocomplete	More niche than pg_trgm	https://github.com/dimitri/prefix
seg	Segment Data Type	Numeric interval type	Scientific/statistical workloads	Rarely used	https://www.postgresql.org/docs/current/seg.html
sslinfo	SSL Connection Info	Inspect SSL connection properties	Security diagnostics	Diagnostic only	https://www.postgresql.org/docs/current/sslinfo.html
tablefunc	Table Functions	Crosstab/pivot utilities	Reporting/analytics	Less flexible than BI tooling	https://www.postgresql.org/docs/current/tablefunc.html
tcn	Triggered Change Notifications	Row change notifications	Event-driven systems	Limited adoption	https://www.postgresql.org/docs/current/tcn.html
test_decoding	Logical Decoding Plugin	Logical WAL decoding test output	CDC experimentation	Not ideal for production CDC	https://www.postgresql.org/docs/current/test-decoding.html
tsearch2	Legacy Text Search	Deprecated full-text search extension	Legacy systems	Deprecated, avoid new usage	https://www.postgresql.org/docs/current/textsearch.html
tsm_system_rows	Table Sampling by Rows	Random row sampling	Analytics/testing	Approximate sampling only	https://www.postgresql.org/docs/current/tsm-system-rows.html
tsm_system_time	Table Sampling by Time	Time-limited sampling	Fast approximate scans	Approximate/non-deterministic	https://www.postgresql.org/docs/current/tsm-system-time.html
unaccent	Accent Removal	Remove accents from text	Search normalization	Locale-specific edge cases	https://www.postgresql.org/docs/current/unaccent.html
uuid-ossp	UUID Generation	UUID generation utilities	Distributed IDs	Often replaced by gen_random_uuid()	https://www.postgresql.org/docs/current/uuid-ossp.html
wal2json	WAL to JSON Decoder	Logical replication JSON output	CDC pipelines	High WAL throughput can be expensive	https://github.com/eulerto/wal2json

Strongly Recommended Extensions by Use Case

Use Case	Recommended Extensions
AI / RAG / Semantic Search	pgvector, pg_trgm, unaccent
Operational Observability	pg_stat_statements, pgAudit, pg_visibility, pg_buffercache
Multi-Tenant SaaS	pg_partman, pg_trgm, citext
CDC / Event Streaming	wal2json, pglogical, test_decoding
Search / Fuzzy Matching	pg_trgm, pg_similarity, prefix, unaccent
GIS / Mapping	postgis, postgis_topology, postgis_raster
Federated Databases	postgres_fdw, mysql_fdw, dblink
AWS Native Integrations	aws_s3, aws_lambda, aws_commons

Extensions Worth Avoiding for Most Modern Systems

Extension	Why
chkpass	Legacy password storage patterns
tsearch2	Deprecated
plcoffee	Extremely niche/obsolete
plls	Extremely niche/obsolete
pltcl	Rarely used in modern environments
hstore	JSONB usually superior
dblink	postgres_fdw generally preferred

Production Guidance

• Prefer pg_stat_statements on virtually every production deployment.
• Prefer pg_trgm for fuzzy search before introducing Elasticsearch/OpenSearch.
• Use pgvector cautiously at scale because ANN/vector indexing can significantly impact memory usage.
• Use pg_partman only when native partitioning management becomes operationally painful.
• Avoid excessive procedural language extensions unless there is a very strong operational reason.
• Be cautious with auditing extensions such as pgAudit because log volume can explode rapidly under high throughput.
• Prefer postgres_fdw over dblink for most federated Postgres access patterns.

Reference documentation sourced from AWS RDS PostgreSQL extension compatibility matrix and upstream PostgreSQL extension documentation. (docs.aws.amazon.com)