Materialized Views

Overview

HeliosDB’s materialized views provide automatic query optimization through pre-computed result caching with intelligent refresh strategies and transparent query rewriting. Materialized views significantly accelerate read-heavy workloads by storing pre-computed query results that are automatically kept up-to-date.

Key Capabilities

Capability	Description	Benefit
Incremental Refresh	Update only changed data	10-100x faster refresh
Flexible Scheduling	Manual, on-commit, interval, cron	Match any workload pattern
Query Rewriting	Automatic view substitution	Transparent optimization
Multiple Storage Backends	LSM, Memory, Columnar, Hybrid	Optimized for use case
Join Elimination	Pre-compute expensive joins	Order of magnitude speedup
Aggregation Pushdown	Pre-compute aggregations	Real-time analytics

Architecture

                        Materialized Views Architecture

  ┌─────────────────────────────────────────────────────────────────────┐
  │                         Query Layer                                  │
  │  ┌─────────────┐    ┌──────────────────┐    ┌─────────────────────┐│
  │  │ SQL Parser  │ -> │  Query Rewriter  │ -> │  Query Executor     ││
  │  └─────────────┘    └──────────────────┘    └─────────────────────┘│
  └──────────────────────────────┬──────────────────────────────────────┘
                                 │
                                 v
  ┌─────────────────────────────────────────────────────────────────────┐
  │                    Materialized View Manager                         │
  │  ┌───────────────┐  ┌─────────────────┐  ┌────────────────────────┐│
  │  │ View Registry │  │ Refresh Manager │  │ Dependency Tracker     ││
  │  └───────────────┘  └─────────────────┘  └────────────────────────┘│
  └──────────────────────────────┬──────────────────────────────────────┘
                                 │
                                 v
  ┌─────────────────────────────────────────────────────────────────────┐
  │                        Storage Layer                                 │
  │  ┌─────────┐  ┌─────────┐  ┌───────────┐  ┌────────────────────────┐│
  │  │   LSM   │  │ Memory  │  │ Columnar  │  │       Hybrid           ││
  │  └─────────┘  └─────────┘  └───────────┘  └────────────────────────┘│
  └─────────────────────────────────────────────────────────────────────┘

Feature Highlights

1. Incremental Refresh

Efficiently update views by processing only changed data.

2. Flexible Refresh Strategies

Strategy	Use Case	Latency
Manual	Development, testing	On-demand
OnCommit	Real-time requirements	Milliseconds
Interval	Regular updates	Seconds to minutes
Cron	Scheduled updates	Any schedule

3. Intelligent Query Rewriting

Automatically substitute materialized views to accelerate queries:

Exact Match: Query matches view definition
Join Elimination: View pre-computes expensive joins
Aggregation Pushdown: View pre-computes aggregations
Superset Match: View contains query data plus more
Filter Pushdown: View has beneficial filters

Performance Benefits

The figures below are indicative, measured on representative fixtures; reproduce on your own hardware.

Scenario	Without MV	With MV	Speedup
Complex Join	500ms	5ms	100x
Large Aggregation	2s	10ms	200x
Dashboard Query	800ms	8ms	100x
OLAP Analytics	5s	50ms	100x

Use Cases

Use Case	Recommended Strategy	Description
Real-time Dashboards	OnCommit	Instant updates
Daily Reports	Cron (midnight)	Scheduled refresh
Session Analytics	Interval (5min)	Near-real-time
Historical Analysis	Manual	On-demand refresh

See Also: HeliosDB Feature Index