---
title: convert_to_columnstore() | Tiger Data Docs
description: Manually add a chunk to the columnstore
---

Since [2.18.0](https://github.com/timescale/timescaledb/releases/tag/2.18.0)

`convert_to_columnstore()` replaces `compress_chunk()`, deprecated in 2.18.0.

Manually convert a specific chunk in the hypertable rowstore to the columnstore.

Although `convert_to_columnstore` gives you more fine-grained control, best practice is to use [`add_columnstore_policy`](/docs/reference/timescaledb/hypercore/add_columnstore_policy/index.md). You can also add chunks to the columnstore at a specific time [running the job associated with your columnstore policy](/docs/reference/timescaledb/jobs-automation/run_job/index.md) manually.

To move a chunk from the columnstore back to the rowstore, use [`convert_to_rowstore`](/docs/reference/timescaledb/hypercore/convert_to_rowstore/index.md).

## Samples

To convert a single chunk to columnstore:

```
CALL convert_to_columnstore('_timescaledb_internal._hyper_1_2_chunk');
```

## Arguments

The syntax is:

```
CALL convert_to_columnstore(
    chunk = '<chunk_name>',
    if_not_columnstore = true | false,
    recompress = true | false
);
```

| Name                 | Type     | Default | Required | Description                                                                                                             |
| -------------------- | -------- | ------- | -------- | ----------------------------------------------------------------------------------------------------------------------- |
| `chunk`              | REGCLASS | -       | ✔        | Name of the chunk to add to the columnstore.                                                                            |
| `if_not_columnstore` | BOOLEAN  | `true`  | ✖        | Set to `false` so this call fails with an error rather than a warning if `chunk` is already in the columnstore.         |
| `recompress`         | BOOLEAN  | `false` | ✖        | Set to `true` to recompress. In-memory recompression is attempted first; it falls back to internal decompress/compress. |

## Returns

This function returns void.