---
title: "Time-Travel Queries - Quick Reference"
---

# Time-Travel Queries - Quick Reference

## SQL Syntax

### AS OF TIMESTAMP
```sql
SELECT * FROM orders AS OF TIMESTAMP '2025-11-15 06:00:00';
SELECT * FROM orders AS OF TIMESTAMP '2025-11-15T06:00:00';
```

### AS OF TRANSACTION
```sql
SELECT * FROM orders AS OF TRANSACTION 987654;
```

### AS OF SCN
```sql
SELECT * FROM orders AS OF SCN 123456789;
```

### AS OF NOW
```sql
SELECT * FROM orders AS OF NOW;
```

## Configuration

Automatic versioning is on by default. Turn it off in `config.toml` for write-heavy
tables that never need history:

```toml
[storage]
time_travel_enabled = true   # default; false disables AS OF queries
```

Old versions are removed by background garbage collection; a timestamp, transaction or
SCN older than the retained history returns an error (see below).

## Error Messages

| Error | Meaning |
|-------|---------|
| "Transaction X not found or has been garbage collected" | Transaction ID has been GC'd or never existed |
| "No snapshot found for timestamp '...'" | No snapshot exists at or before that time |
| "Invalid timestamp format:..." | Timestamp string couldn't be parsed |
| "SCN X not found or has been garbage collected" | SCN has been GC'd or never existed |

## Performance Tips

- **Use TXN/SCN over TIMESTAMP**: Faster resolution (no string parsing)
- **Tune retention**: Balance history needs vs performance
- **Target overhead**: <2x vs non-time-travel queries

## Examples

### Query Past State
```sql
-- Orders as they existed at transaction 50
SELECT * FROM orders AS OF TRANSACTION 50;
```

### Audit Trail
```sql
-- Compare a row now with the same row at an earlier time
SELECT * FROM orders WHERE id = 42;
SELECT * FROM orders AS OF TIMESTAMP '2025-11-15 06:00:00' WHERE id = 42;
```

### Point-in-Time Recovery
```sql
-- Data as it was just before an incident
SELECT * FROM orders AS OF TIMESTAMP '2025-11-15 05:59:00';

-- Or fork a branch at that instant and inspect it in isolation
CREATE BRANCH before_incident FROM main AS OF TIMESTAMP '2025-11-15 05:59:00';
```

## See Also

- [Time Travel Queries Tutorial](/docs/lite/guides/tutorials/time_travel_tutorial/)
- [Database Branching Tutorial](/docs/lite/guides/tutorials/database_branching_tutorial/)