---
title: "HeliosDB-Lite System View Catalog"
---

# HeliosDB-Lite System View Catalog

94 system views (internal count for the current release) are available via `SELECT * FROM <view_name>`; `helios_dictionary` lists the views your build provides. The Filter Advisor views (`helios_filter_*`) are present but not yet populated; automatic per-column filter selection is planned.

To list all views: `SELECT * FROM helios_dictionary`
To filter by category: `SELECT view_name, description FROM helios_dictionary WHERE category = 'security'`

## Catalog (11 views)

| View | Description |
|------|-------------|
| `pg_tables` | List of all user tables |
| `pg_views` | List of all views |
| `pg_indexes` | List of all indexes |
| `pg_attribute` | Table column attributes (name, type, nullable) |
| `pg_class` | Relations (tables, indexes, sequences, views) |
| `pg_type` | Registered data types |
| `pg_namespace` | Schemas and namespaces |
| `pg_index` | Index definitions with column mappings |
| `pg_constraint` | Constraints (PK, FK, UNIQUE, CHECK) |
| `pg_database` | Database metadata |
| `pg_matviews` | Materialized views and their definitions |

## Session & Activity (5 views)

| View | Description |
|------|-------------|
| `pg_stat_activity` | Currently running queries, session state, wait events |
| `pg_stat_database` | Database-wide statistics (transactions, blocks, tuples) |
| `pg_settings` | Runtime configuration parameters and their values |
| `pg_stat_ssl` | SSL/TLS connection status per session |
| `pg_authid` | Authentication identities (users and roles) |

## Statistics (5 views)

| View | Description |
|------|-------------|
| `pg_stats` | Column statistics from ANALYZE (null_frac, n_distinct, avg_width) |
| `pg_stat_optimizer` | Optimizer cost estimation accuracy and rule usage |
| `helios_table_memory_stats` | Per-table memory consumption |
| `helios_query_history` | Recent query execution log with timing |
| `helios_transaction_stats` | Transaction commit/rollback throughput |

## Security (5 views)

| View | Description |
|------|-------------|
| `helios_grants` | Table and column privilege grants (GRANT/REVOKE) |
| `helios_roles` | Roles with options (LOGIN, SUPERUSER, RATE_LIMIT, SSL_REQUIRED) |
| `helios_user_quotas` | Per-user rate limit quotas and current usage |
| `pg_rls_policies` | Row-level security policies (USING/CHECK expressions) |
| `pg_tenant_usage` | Multi-tenant resource usage per tenant |

## Encryption (5 views)

| View | Description |
|------|-------------|
| `pg_encryption_status` | TDE encryption global status |
| `pg_table_encryption` | Per-table encryption status |
| `pg_segment_encryption` | Per-storage-segment encryption status |
| `helios_encryption_keys` | Encryption key versions and rotation history |
| `helios_zke_status` | Zero-knowledge encryption per-table status |

## HTAP (3 views)

| View | Description |
|------|-------------|
| `pg_htap_layout_stats` | Row store vs columnar store size statistics |
| `helios_workload_patterns` | OLTP/OLAP/HTAP workload classification patterns |
| `helios_resource_usage` | HTAP resource quota usage (CPU, memory, I/O) |

## Storage (12 views)

| View | Description |
|------|-------------|
| `helios_bloom_filters` | Bloom filter FPR and memory per column |
| `helios_zone_maps` | Zone map min/max boundaries per column |
| `helios_index_stats` | Index metadata (type, column, size, entries) |
| `helios_smfi_status` | Self-maintaining filter index lifecycle status |
| `helios_dedup_stats` | Content-addressed deduplication ratios |
| `helios_prefetch_stats` | Read prefetch cache statistics |
| `helios_column_compression` | Per-column compression codec (zstd/lz4/none) |
| `pg_compression_stats` | Global compression statistics |
| `pg_block_file_stats` | Block file I/O statistics |
| `pg_wal_stats` | Write-ahead log size, segments, sync stats |
| `pg_segment_stats` | Storage segment utilization |
| `pg_staging_area_stats` | Staging area (bulk load) statistics |

## Branching & Time Travel (7 views)

| View | Description |
|------|-------------|
| `pg_branches` | Database branches (name, created_at, parent) |
| `pg_database_branches` | Branch metadata and lineage tree |
| `pg_branch_stats` | Per-branch row count and size statistics |
| `pg_compare_branches` | Compare data between two branches |
| `pg_snapshots` | MVCC snapshot history |
| `pg_scn_map` | System change number mapping |
| `pg_transaction_map` | Transaction ID to timestamp mapping |

## Materialized Views (2 views)

| View | Description |
|------|-------------|
| `helios_mv_refresh_status` | Views with a `refresh_interval` set through `ALTER MATERIALIZED VIEW ... SET`; automatic refresh is planned |
| `pg_mv_staleness` | How stale each MV is (rows changed since refresh) |

## HA & Replication (9 views)

| View | Description |
|------|-------------|
| `pg_stat_replication` | Active replication connections |
| `pg_replication_status` | Cluster replication health |
| `pg_replication_standbys` | Standby Server state and lag |
| `pg_replication_primary` | Primary server information |
| `pg_replication_metrics` | Replication throughput and latency |
| `helios_ha_status` | HA cluster Overall readiness |
| `helios_topology` | Cluster node topology |
| `helios_node_aliases` | Node alias name mappings |
| `helios_sync_status` | Sync module replication status |

## Proxy (14 views)

| View | Description |
|------|-------------|
| `helios_proxy_status` | Proxy Server state |
| `helios_proxy_pools` | Connection pool status and utilization |
| `helios_proxy_cache_stats` | Query result cache hit rates |
| `helios_proxy_routing_stats` | Query routing decisions |
| `helios_proxy_lag_stats` | Lag-aware read routing statistics |
| `helios_proxy_rate_limit_stats` | Rate limiting enforcement stats |
| `helios_proxy_circuit_breaker_stats` | Circuit breaker state transitions |
| `helios_proxy_analytics_stats` | Query analytics (slow queries, patterns) |
| `helios_proxy_auth_stats` | Authentication proxy statistics |
| `helios_proxy_rewriter_stats` | Query rewriter rule application stats |
| `helios_proxy_plugin_stats` | WASM plugin execution stats |
| `helios_proxy_graphql_stats` | GraphQL gateway request stats |
| `helios_proxy_schema_routing_stats` | Schema-based routing stats |
| `pg_distribcache_stats` | Distributed cache hit rates |

## Maintenance (2 views)

| View | Description |
|------|-------------|
| `pg_stat_progress_vacuum` | VACUUM progress (tables processed, rows removed) |
| `pg_maintenance_stats` | Background maintenance task statistics |

## Features (5 views)

| View | Description |
|------|-------------|
| `helios_graphql_status` | GraphQL gateway enabled/endpoint status |
| `helios_circuit_breaker_status` | Circuit breaker config and current state |
| `helios_extensions` | Installed WASM extensions |
| `pg_publications` | Logical replication publications |
| `pg_subscriptions` | Logical replication subscriptions |

## Observability (3 views)

| View | Description |
|------|-------------|
| `helios_audit_log` | Registered for the planned built-in audit log; returns no rows today |
| `helios_advisor_recommendations` | Registered for planned index and query recommendations; returns no rows today |
| `pg_cdc_events` | Change data capture event log |

## Vector (1 view)

| View | Description |
|------|-------------|
| `pg_vector_index_stats` | HNSW index build stats, search accuracy |

## Filter Subsystem (4 views)

| View | Description |
|------|-------------|
| `pg_smfi_status` | SMFI filter lifecycle status |
| `pg_smfi_table_stats` | SMFI per-table filter statistics |
| `pg_speculative_filters` | Speculative filter effectiveness |
| `pg_access_tracker_stats` | Access pattern tracking for filter advisor |

## Meta (1 view)

| View | Description |
|------|-------------|
| `helios_dictionary` | **This catalog** — lists all system views with descriptions |

---

## Quick Examples

```sql
-- What tables exist?
SELECT * FROM pg_tables;

-- Who has access to what?
SELECT * FROM helios_grants;

-- Is my query OLTP or OLAP?
EXPLAIN ANALYZE SELECT ...;  -- shows workload classification

-- What indexes exist and how big are they?
SELECT * FROM helios_index_stats;

-- Recent query performance
SELECT * FROM helios_query_history;

-- All views in a category
SELECT view_name FROM helios_dictionary WHERE category = 'security';
```