Configuration

Server Configuration

Configuration via environment variables (recommended) or CLI flags.

Storage Engine Configuration

StoreConfig controls engine behavior. Set via code when embedding, or via future config file support (v0.2).

#![allow(unused)]
fn main() {
pub struct StoreConfig {
    /// Root directory for WAL, segments, and index files.
    pub data_dir: PathBuf,

    /// Flush MemTable to segment when in-memory size exceeds this threshold.
    /// Default: 64MB. Larger = fewer flushes, more memory usage.
    pub memtable_flush_size: usize,

    /// Maximum WAL segment file size before rotation.
    /// Default: 64MB. After rotation, a new wal-{n}.pxw file starts.
    pub wal_segment_max_size: u64,
}
}

Data Directory Layout

After starting the server, the data directory has this structure:

parallax-data/
├── wal/
│   ├── wal-00000000.pxw    ← WAL segments (binary, PXWA format)
│   ├── wal-00000001.pxw
│   └── ...
└── segments/
    ├── seg-00000000.pxs    ← Immutable segment files (binary, PXSG format)
    ├── seg-00000001.pxs
    └── ...

Both WAL and segment files are binary and not human-readable. Use parallax stats to inspect the current state.

Query Limits

Default limits applied to all queries:

These are currently hardcoded. Per-query overrides and global configuration are planned for v0.2.

Logging

Parallax uses tracing for structured logging. Configure with RUST_LOG:

# Common patterns
RUST_LOG=info parallax serve           # Default
RUST_LOG=debug parallax serve          # Verbose
RUST_LOG=parallax_store=trace parallax serve  # Trace storage only
RUST_LOG=parallax=debug,tower_http=warn parallax serve  # App debug, HTTP quiet

Log format (JSON) is planned for v0.2. Current format is human-readable text.

Production Recommendations

# Full production configuration
export PARALLAX_HOST=0.0.0.0
export PARALLAX_PORT=7700
export PARALLAX_DATA_DIR=/var/lib/parallax
export PARALLAX_API_KEY=$(openssl rand -hex 32)
export RUST_LOG=info

parallax serve

Storage:

• Mount PARALLAX_DATA_DIR on a fast SSD
• Ensure at least 10GB free space for WAL and segments
• Set up log rotation for WAL files (automatic in v0.2)

Security:

• Generate a cryptographically random API key
• Terminate TLS at the load balancer or reverse proxy
• Restrict network access to the parallax port
• Never log the PARALLAX_API_KEY

Monitoring:

• Scrape /metrics with Prometheus
• Alert on parallax_errors_total increases
• Monitor parallax_entities_total for unexpected spikes or drops