# Background Processor

The Background Processor continuously polls the Redis transaction buffer and executes transactions against the main database.

```{contents} Table of Contents
:depth: 2
:local: true
```

## Core Implementation

Key code from `background_processor.py`:

```{literalinclude} ../../../ccat_ops_db_api/transaction_buffering/background_processor.py
:emphasize-lines: 10-20, 71-80
:language: python
:lines: 19-100
```

## Processing Loop

1. **Check buffer size** (LLEN)
2. **Check database connectivity**
3. **Pop transaction** (RPOP)
4. **Execute transaction** on main database
5. **Capture LSN** after commit
6. **Track replication** via LSN tracker
7. **Cleanup or extend cache** based on replication

## Configuration

```bash
BACKGROUND_PROCESSING_INTERVAL=1.0  # seconds
TRANSACTION_RETRY_ATTEMPTS=3
TRANSACTION_RETRY_DELAY=5  # seconds
```

## Health Monitoring

The processor reports health via `/health` endpoint:

```json
{
  "background_processor": {
    "status": "running",
    "last_run": "2025-01-01T00:00:05Z",
    "transactions_processed": 150
  }
}
```

## Next Steps

- {doc}`lsn-tracking` - How replication is tracked
- {doc}`../../development/debugging-buffering` - Troubleshooting