---
title: Mixed Fast Fields
---

## Mixed Fast Fields Execution

The Mixed Fast Fields execution state (`MixedFastFieldExecState`) is a specialized execution method for handling both multiple string fast fields and mixed string/numeric fast fields in a single query. By default, this execution method is disabled in favor of more stable execution methods.

To enable the Mixed Fast Fields execution state:

```sql
SET paradedb.enable_mixed_fast_field_exec = true;
```

### When to Use

Mixed Fast Fields execution can provide performance benefits in queries that:

1. Use multiple string fast fields in a single query
2. Use a combination of string and numeric fast fields in a single query

This is particularly useful in complex join queries where multiple fast fields need to be accessed efficiently.

### Trade-offs

While the Mixed Fast Fields execution state can provide performance improvements, it's disabled by default because:

1. It's a newer feature that may have edge cases not covered by existing tests
2. The standard execution methods are well-tested and stable for most use cases

If you're experiencing performance issues with complex queries involving multiple fast fields, enabling this feature flag might help.

### Usage in Production

We recommend testing thoroughly in a staging environment before enabling this feature in production. You can permanently enable it in your `postgresql.conf` file:

```
paradedb.enable_mixed_fast_field_exec = true
```