DATA PLATFORM & EXTENSIONS
Extend the database where the documented capability fits.
Halo combines a broad SQL object model with optional modules for diagnostics, indexing, text processing, federation, security, data types, events, and sampling. Its catalogs also document a modest in-database model/runtime foundation.
Optional modules expand a stable core
The manual documents 45 extensions. They are organized by purpose so visitors can discover capability without navigating function signatures or setup procedures.
- 12administration and diagnostics
- Integrity, plans, cache, storage, workload, lock, and TLS inspection.
- 9indexing and search
- Alternative opclasses, case handling, dictionaries, fuzzy and trigram search, accents.
- 12types and transformations
- Multidimensional, hierarchical, semi-structured, identifier, large-object, pivot, UUID, and XML utilities.
- 12integration, security, and events
- Foreign access, hashing/crypto, SELinux labels, notifications, decoding hooks, and sampling.
Browse all documented modules by purpose
Administration, integrity, and diagnostics12 modules
Server administration, index integrity, automatic plan logging, page/cache/free-space inspection, prewarming, row locks, workload statistics, tuple/index bloat, visibility, and TLS connection details.
- adminpack
- amcheck
- auto_explain
- pageinspect
- pg_buffercache
- pg_freespacemap
- pg_prewarm
- pgrowlocks
- pg_stat_statements
- pgstattuple
- pg_visibility
- sslinfo
Indexing, search, and text processing9 modules
Bloom supplies compact, lossy equality signatures that can return false-positive candidates for recheck. B-tree-equivalent GIN/GiST operator classes, locale-dependent case-insensitive text, text dictionaries, fuzzy algorithms, trigram similarity, and accent normalization cover different search patterns rather than one interchangeable index family.
- bloom
- btree_gin
- btree_gist
- citext
- dict_int
- dict_xsyn
- fuzzystrmatch
- pg_trgm
- unaccent
Data types and transformations12 modules
Capabilities include cubes with a documented 100-dimension limit, spherical—not GIS—distance utilities, single-value text key/value data, non-null integer-array operations, publishing identifiers whose prefix data may need updating, large-object references with separate orphan handling, hierarchies, seven-significant-digit uncertainty intervals, pivot/hierarchy functions, UUID variants, and XML/XPath with build-dependent XSLT support. intagg is deprecated.
- cube
- earthdistance
- hstore
- intagg
- intarray
- isn
- lo
- ltree
- seg
- tablefunc
- uuid-ossp
- xml2
External and federated access3 modules
Session-level database links, server-file foreign tables, and standards-oriented PostgreSQL-compatible foreign tables.
- dblink
- file_fdw
- postgres_fdw
Security and security labeling4 modules
Authentication delay can slow brute-force attempts but is not denial-of-service protection. Password-policy checks, hashing/HMAC/password hashing/PGP/randomness, and SELinux-integrated mandatory access checks for supported operations each have distinct boundaries.
- auth_delay
- passwordcheck
- pgcrypto
- sepgsql
Events, decoding, and sampling5 modules
Trigger examples, row-change notification, a logical-decoding development example, and row- or time-limited sampling are documented. The sampling methods do not promise a random or repeatable sample, and the examples do not become production CDC services by name alone.
- spi
- tcn
- test_decoding
- tsm_system_rows
- tsm_system_time
Connect data without turning the page into a tutorial
Halo’s extension set includes database links, file foreign tables, and PostgreSQL-compatible foreign servers. Each connector has its own transaction, security, and pushdown behavior.
Query and object model
Foreign tables and remote relationships participate in local planning.
Standards-oriented federation
Connection reuse, schema import, safe filter/projection/join pushdown, local transaction mapping, and remote statistics. Remote prepared 2PC is not supported.
Session-level remote access
Named connections, queries, commands, cursors, asynchronous results, notifications, and inspection. postgres_fdw is the preferred higher-level path where it fits.
Server-file foreign tables
COPY-readable files or controlled program output can become queryable tables; privileged file/program access requires careful security handling.
Do not generalize remote ACID, pushdown, or performance beyond each connector’s documented behavior. postgres_fdw does not prepare a remote transaction for two-phase commit.
Data, search, analytics, and security capabilities
Text and similarity
Integer and synonym dictionaries, fuzzystrmatch algorithms, trigram similarity and indexed LIKE/regex, accent-insensitive text search, and case-insensitive citext support different search needs and language boundaries.
Specialized data
cube, hstore, intarray, ltree, seg, ISN identifiers, large-object references, UUID variants, XML/XPath, spherical-distance utilities, and table pivot/hierarchy functions extend the data model without implying a full GIS or analytics platform.
Events and change surfaces
LISTEN/NOTIFY and tcn row-change notifications expose event primitives. test_decoding is a development example, not a production CDC connector or delivery guarantee.
Cryptographic functions
pgcrypto provides digest and HMAC functions, salted password hashing, PGP symmetric/public-key operations, secure random bytes, and UUID generation. It does not establish encryption at rest or end-to-end protection, and trusted SSL/client-server handling remains necessary.
Security controls
Roles, privileges, row-level policies, security labels, optional authentication delay, and optional SELinux MAC for supported objects complement each other. None should be described as a complete security posture by itself.
Eleven Halo catalogs extend database introspection
Compatibility object registries
Synonyms, registered directories, database links, recycle-bin objects, packages, type bodies, session/package variables, and view definitions are exposed through Halo-specific metadata.
- pg_synonym
- pg_directory
- pg_dblink
- pg_dbarecyclebin
- pg_package
- pg_typebody
- pg_variable
- pg_viewdef
Runtime and query registries
Model definitions, runtime handlers, and Oracle-style SQL query mapping are represented in dedicated catalogs.
- pg_model
- pg_mrt
- pg_querymap
MRT at its documented scope
The manual identifies an in-database model/runtime mechanism. pg_model holds model-definition metadata such as name, type, provider, algorithm, options, and access information; pg_mrt maps runtime names to handlers. The inspected manual snapshot records a GGUF-related runtime handler.
This establishes a catalog and handler foundation to evaluate. It does not establish a supported-model matrix, public inference API, sizing guidance, hardware acceleration, or packaging availability. DataOS has no basis in the canonical Markdown and is not published as a Halo capability.
Evaluate the module, not just the name
- Availability in the target Halo build
- Module version and upgrade path
- Operating-system or database dependencies
- Privilege and security implications
- Remote transaction and pushdown behavior
- Observation overhead for diagnostic modules
- Model and runtime support required by the workload
The right claim is the capability documented for a selected build—not an assumption that every module is installed, enabled, or suitable for every workload.