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HeliosDB HeliosDB Nano

HeliosDB Nano Feature Index

Canonical feature × tutorial coverage map. Every available feature has an entry here with a short description and a link to a hands-on tutorial or quick reference.

For the release history, see the changelog.

The Coverage column rates how thoroughly each feature is documented:

  • 5/5: long-form tutorial plus quick reference
  • 4/5: tutorial, or several references with code examples
  • 3/5: reference page with examples
  • 2/5: brief mention in the release notes or README
  • 1/5: mentioned only in the changelog

SQL / DML / Query Execution

FeatureSummaryCoverageDoc
Full SQL CoreJOINs, CTEs, subqueries, set ops, aggregates, CASE4/5SQL_REFERENCE
Aggregate expressionsSUM(a)+SUM(b), CAST(AVG()), CASE on COUNT3/5SQL_FEATURES
Window functionsFull SQL:2003 frame spec3/5WINDOW_FUNCTIONS_QUICKREF
Common table expressionsWITH RECURSIVE depth control3/5SQL_FEATURES
SubqueriesScalar, derived, IN/EXISTS3/5SQL_FEATURES
String concatenation ||NULL propagation, auto-cast2/5CHANGELOG
EXTRACT / date functionsEPOCH, YEAR, MONTH, etc.3/5release notes
INSERT … SELECTFK/trigger/RLS-aware bulk insert3/5SQL_FEATURES
ON CONFLICT (Upsert)DO UPDATE SET … EXCLUDED + MySQL ON DUPLICATE KEY3/5UPSERT_QUICKREF
Parameterized LIMIT/OFFSETLIMIT $1 OFFSET $2 with type coercion3/5release notes
Keyset paginationConstant-time deep pagination (~30 µs)5/5KEYSET_PAGINATION_QUICKREF, release notes
Top-K sort optimizationLIMIT-driven early termination, O(N log k)3/5release notes
Generate_series / unnestTable-valued functions2/5CHANGELOG
EXPLAIN / cost plannerJSON/XML/YAML output, ANALYZE4/5EXPLAIN_AND_OPTIMIZATION
Implicit comma-joinsFROM t1, t2 WHERE … (WordPress compat)2/5CHANGELOG
Recursive CTEsDepth-limited graph traversal in SQL3/5SQL_FEATURES
gen_random_uuid / uuid_generate_v4UUID generation2/5release notes

DDL / Schema

FeatureSummaryCoverageDoc
CREATE TABLEAll constraints + DEFAULT expressions + CHECK4/5SQL_REFERENCE
PRIMARY KEY (inline + table)Both syntaxes3/5primary-keys
Foreign keysCASCADE, SET NULL, RESTRICT4/5foreign-keys
UNIQUE constraintsPer-column + multi-column; ON CONFLICT detection3/5SQL_FEATURES
CHECK constraintsExpression-based row validation3/5SQL_FEATURES
GENERATED ALWAYS AS IDENTITYSQL:2016 identity columns3/5release notes
SERIAL / BIGSERIAL / AUTO_INCREMENTPG + MySQL alias3/5SQL_REFERENCE
DEFAULT expressionsDEFAULT now(), DEFAULT CURRENT_USER3/5CHANGELOG
ALTER TABLEMultiple ops in single stmt3/5SQL_REFERENCE
CREATE INDEXB-tree, ART, HNSW, GIN4/5vector-search, STORAGE_FILTERING
CREATE SEQUENCE / nextvalProcess-scoped sequence store3/5release notes
CREATE EXTENSION hdb_codeCode-graph bootstrap (opt-in)3/5CODE_GRAPH_TUTORIAL
CREATE SEMANTIC HASH INDEXMerkle-tree subtree invalidation3/5SEMANTIC_HASH_INDEX_QUICKREF
TRUNCATEFast clear with ART purge3/5SQL_FEATURES
Per-column storage modesDictionary / Content-Addressed / Columnar4/5per-column-storage

Indexing & Search

FeatureSummaryCoverageDoc
Adaptive Radix Tree (ART)Zero-copy PK lookups, O(k)3/5PRODUCT_QUANTIZATION_IMPLEMENTATION
HNSW vector searchNative k-NN, about 16x (internal tests, Nano 3.32.1 vs unquantized HNSW, see benchmarks) PQ5/5VECTOR_SEARCH_TUTORIAL
BM25 full-text searchtsvector / tsquery / @@ / ts_rank_cd4/5FULL_TEXT_SEARCH
Hybrid searchBM25 + vector via RRF/MMR4/5FULL_TEXT_SEARCH
GIN indexes (FTS)ORM/migration compat (no-op currently)2/5release notes
SIMD predicate pushdownStorage-level filtering via bloom/zone-map/SIMD3/5STORAGE_FILTERING
Centrality-biased HNSWPost-rerank with centrality weighting3/5release notes
UUID literal coercionPK lookup with UUID columns3/5release notes

Transactions / Concurrency / MVCC

FeatureSummaryCoverageDoc
ACID transactionsSnapshot isolation, all-or-nothing4/5SQL_REFERENCE
Explicit transactionsBEGIN / COMMIT / ROLLBACK3/5SQL_REFERENCE
SavepointsNested rollback boundaries3/5SQL_FEATURES
MVCCSnapshot iso, read-your-writes4/5../architecture/multi_user_transactions.md
Optimistic conflict detection (sync-experimental build)Vector clocks, field-level merge2/5CHANGELOG

Time-Travel / Branching

FeatureSummaryCoverageDoc
Git-like branchesCOW isolation for dev/test/A-B5/5branching and time-travel tutorial, branching
Selective branch syncReplicate specific branches to remotes3/5release notes
AS OF TIMESTAMPQuery historical snapshots5/5time-travel, branching and time-travel tutorial
AS OF TRANSACTIONQuery by txn ID4/5time-travel
MERGE BRANCH / DROP BRANCHBranch lifecycle4/5branching
ON BRANCH overridePer-call branch redirect (MCP/LSP)3/5release notes

Encryption / Security / Compliance

FeatureSummaryCoverageDoc
AES-256-GCM TDEDatabase-level transparent encryption5/5ENCRYPTION_TUTORIAL, ENCRYPTION
FIPS 140-3 (feature flag)AWS-LC FIPS provider, Cert #48164/5FIPS_COMPLIANCE_TUTORIAL
SCRAM-SHA-256 authPG-standard password hashing3/5SCRAM_SHA256_AUTHENTICATION
TLS / SSLEncrypted wire (PG + MySQL)3/5POSTGRESQL_SSL_QUICK_REFERENCE
Row-Level Security (RLS)Per-tenant isolation via policies (embedded API and REPL; SQL CREATE POLICY and wire/REST enforcement planned)4/5RLS_POLICY_MANAGEMENT_TUTORIAL, rls
JWT sessionsStateless auth3/5JWT_AUTH_QUICK_REFERENCE
OAuth2 (Google/GitHub)PKCE, auto user creation4/5AUTH_AND_OAUTH
Audit loggingTamper-proof SHA-256 chain5/5AUDIT_LOGGING_TUTORIAL, AUDIT_LOGGING
Argon2id KDFMemory-hard password hashing3/5ENCRYPTION_TUTORIAL

Stored Procedures / Triggers / Functions

FeatureSummaryCoverageDoc
PL/pgSQL functions and proceduresSQL statements, SELECT INTO, RETURN; control flow (IF / LOOP / WHILE / FOR / RAISE) planned3/5procedural-language
TriggersAccepted; bodies run only for BEFORE-row NEW.col = expr assignments (full trigger bodies planned)4/5triggers, TRIGGER_EXECUTION_QUICK_REFERENCE
Scalar functions100+ built-in4/5SQL_REFERENCE
Aggregate functionsCOUNT, SUM, AVG, MIN, MAX, STDDEV4/5SQL_REFERENCE
User-defined functionsComposite types via JSON3/5SQL_REFERENCE

JSON / JSONB

FeatureSummaryCoverageDoc
JSONB typeSchemaless docs4/5SQL_REFERENCE
JSONB operators->, ->>, @>, ?, #-4/5SQL_REFERENCE
JSON path queriesNested navigation3/5SQL_REFERENCE
json_aggJSON array aggregation3/5CHANGELOG

Backend-as-a-Service (BaaS)

FeatureSummaryCoverageDoc
REST API (PostgREST-style)eq, neq, gt, gte, lt, lte, like, ilike, is, in plus not. on /rest/v1/{table} (the table routes are a known issue in the current release; more operators planned)5/5BAAS_REST_API_TUTORIAL
Auth signup/token/auth/v1/signup, /auth/v1/token4/5AUTH_AND_OAUTH
OAuth2 Google/GitHubPKCE flow4/5AUTH_AND_OAUTH
RLS on REST (planned)JWT-based row-level security for REST requests3/5BAAS_REST_API_TUTORIAL
Realtime WebSocketPhoenix-protocol channels. Known issue: realtime events are not delivered in the current release; tracked by the Nano team5/5REALTIME_WEBSOCKET
ChangeNotifierEvent broadcast for REST table writes2/5CHANGELOG
Swagger UIAuto-generated /docs3/5SWAGGER_UI_QUICKSTART

Protocol Compatibility

FeatureSummaryCoverageDoc
PostgreSQL Wire v3psql, libpq, psycopg2, pg, JDBC5/5POSTGRESQL_WIRE_PROTOCOL
PG Extended QueryParse / Bind / Execute / Describe3/5PARAMETERIZED_QUERIES
MySQL Wire v10mysql, JDBC, mysql2, mysqli, WordPress5/5MYSQL_WIRE
MySQL Prepared Stmts$N substitution, COM_STMT_PREPARE3/5MYSQL_WIRE
Unix Domain SocketsZero-TCP for same-host4/5UNIX_SOCKETS_QUICKSTART
Flush message (H)Pipelined queries2/5CHANGELOG
Multi-statement queries;-separated stmts3/5release notes
MySQL SHOW commandsSHOW TABLES/COLUMNS/INDEX3/5CHANGELOG
MySQL date/time functionsDATE_FORMAT, DATE_ADD, UNIX_TIMESTAMP3/5CHANGELOG
MySQL identifier quotingBacktick / double-quote / case-folding3/5release notes
heliosdb_capability_report()Migration tool discovery3/5release notes

Materialized Views

FeatureSummaryCoverageDoc
MV creationPersistent query results5/5MATERIALIZED_VIEWS_TUTORIAL
Refresh MVFull recompute4/5materialized-views
Incremental MVDelta computation4/5INCREMENTAL_MATERIALIZED_VIEWS
Concurrent MV refreshMulti-MV in parallel3/5CONCURRENT_MV_REFRESH_QUICK_REF
MV schedulerCPU-aware auto refresh3/5MATERIALIZED_VIEWS_TUTORIAL
MV dependency trackingCascading invalidation3/5INCREMENTAL_MATERIALIZED_VIEWS

Code-Graph (opt-in --features code-graph)

FeatureSummaryCoverageDoc
Code-graph bootstrapTree-sitter AST for 8 languages4/5CODE_GRAPH_TUTORIAL
Symbol extractionFunctions, classes, methods, types3/5CODE_GRAPH_TUTORIAL
Reference resolutionCross-file linking (exact/heuristic)3/5release notes
lsp_definition”Where is X defined?“4/5CODE_GRAPH_TUTORIAL
lsp_references”Who uses X?“4/5CODE_GRAPH_TUTORIAL
lsp_call_hierarchyBFS over CALLS edges4/5CODE_GRAPH_TUTORIAL
lsp_hoverSignature lookup3/5CODE_GRAPH_TUTORIAL
lsp_document_symbolsFile outline3/5release notes
lsp_rename_preview/applyIdentifier-boundary write-back3/5release notes
Symbol embeddingsbody_vec VECTOR(n) lazy column3/5CODE_GRAPH_TUTORIAL
Pluggable embeddersNoopEmbedder + HttpEmbedder3/5CODE_GRAPH_TUTORIAL
code-embed featurefastembed-rs (BGESmallENV15, 384-dim)3/5CODE_GRAPH_TUTORIAL
Runtime grammar registryDynamic grammar loading2/5CHANGELOG
Pluggable extractorsPer-language runtime registration2/5CHANGELOG
Semantic Hash IndexMerkle-tree subtree invalidation3/5SEMANTIC_HASH_INDEX_QUICKREF
_hdb_code_languages viewList static + runtime grammars2/5CHANGELOG

Graph-RAG (opt-in --features graph-rag)

FeatureSummaryCoverageDoc
Universal node/edge schema_hdb_graph_nodes & _hdb_graph_edges plain tables4/5GRAPH_RAG_TUTORIAL
Symbol projectiongraph_rag_project_symbols()3/5GRAPH_RAG_TUTORIAL
BFS graph searchSeed → expand → subgraph4/5GRAPH_RAG_TUTORIAL
Centrality weightingPost-rerank scoring bias3/5GRAPH_RAG_TUTORIAL
Vector entity linkerCross-modal MENTIONS via cosine3/5GRAPH_RAG_TUTORIAL
Docling PDF/Office ingestiongraph_rag_ingest_*4/5DOCLING_INGESTION
Graph traversal toolsheliosdb_graph_traverse / _path / _add_edge3/5release notes

MCP Endpoint (opt-in --features mcp-endpoint)

FeatureSummaryCoverageDoc
MCP JSON-RPC dispatcherNative server for Claude Code/Cursor/Aider5/5MCP_ENDPOINT
16-tool catalogue10 DB-backed + 6 RAG4/5MCP_ENDPOINT
MCP resource URIsheliosdb://schema/{table} etc.3/5MCP_ENDPOINT
WebSocket transportReal-time tool calls3/5MCP_ENDPOINT
Stdio transportLibrary only (no engine subcommand); for stdio MCP use the HeliosDB CodeKB MCP binary3/5MCP_ENDPOINT
SSE transportServer-sent events3/5MCP_ENDPOINT
Progress notificationsStreaming notifications/progress3/5MCP_ENDPOINT
HTTP POST + SSE pairingForward progress to SSE2/5release notes
Verbose tool discoverytools/list?verbose=true + helios/info3/5MCP_ENDPOINT

Persistence / WAL / Replication

FeatureSummaryCoverageDoc
RocksDB LSM storageWrite-optimised KV store3/5../architecture
Write-ahead logDurability guarantee3/5WAL_QUICK_REFERENCE
WAL streaming replication (default build)Warm standby, async repl4/5HA_HANDS_ON_TUTORIAL
Branch-based replication (ha-tier2/branch-replication build)Selective branch sync3/5release notes
Multi-primary active-active (ha-tier2 build)Vector-clock conflict resolution3/5high-availability
Sharding (ha-tier3 build)Consistent hash ring3/5high-availability
Content-addressed dedup (ha-dedup build)Cross-node BLAKE3 dedup3/5high-availability
In-memory mode--memory for tests/CI3/5IN_MEMORY_MODE_QUICKREF

Backup / Restore / Dump

FeatureSummaryCoverageDoc
Database dumpzstd / gzip / brotli / lz44/5BACKUP_RESTORE
Selective exportPer-table/schema3/5BACKUP_RESTORE
Import/export formatsCSV, JSON, JSONL, Parquet, Arrow, SQL3/5BACKUP_RESTORE
SQLite importOne-shot .sqlite conversion3/5features/sqlite/

Observability

FeatureSummaryCoverageDoc
Tracing / structured loggingtracing macros3/5TRACING_GUIDE
EXPLAIN ANALYZECost-based plans, JSON/XML/YAML4/5EXPLAIN_AND_OPTIMIZATION
CPU monitoring (sysinfo)MV scheduler awareness2/5CHANGELOG
Result cache128-entry LRU + dml/ddl invalidation3/5CHANGELOG
Audit logTamper-proof SHA-2565/5AUDIT_LOGGING_TUTORIAL

Embedded Rust API

FeatureSummaryCoverageDoc
In-process databaseZero-network, no daemon4/5API_REFERENCE, docs.rs
Async runtime (Tokio)Non-blocking I/O3/5API_REFERENCE
Code indexing APIcode_index(opts) idempotent3/5CODE_GRAPH_TUTORIAL
Branch operationscreate/switch/list/merge3/5API_REFERENCE
Transaction controlbegin/commit/rollback/savepoint3/5API_REFERENCE

SDKs & Bindings

LanguageUVPDoc
Rust (heliosdb-nano)Embedded APIdocs.rs
Python (@heliosdb/client-equiv)psycopg2 + REST + Realtimeapi/python-sdk.md, PYTHON_VECTOR_APP
TypeScript (@heliosdb/client)REST + Realtime + Auth fluent APIapi/typescript-sdk.md, NODEJS_BAAS_APP
Gopgx-style + RESTapi/go-sdk.md, GO_EMBEDDED_APP
ORMs (any)SQLAlchemy / Django / Prisma / Drizzle / TypeORM / Sequelize / Hibernate / GORM / SeaORM / DieselORM_SUPPORT, DRIZZLE_PRISMA_COMPAT

Tooling / CLI

FeatureSummaryCoverageDoc
heliosdb-nano binary~32 MB single executable4/5README
REPLZero-setup interactive SQL4/5REPL_COMMAND_REFERENCE
Release binaries / crates.io / container imageGitHub Releases binaries, cargo install heliosdb-nano, ghcr.io/heliosdatabase/heliosdb-nano4/5README