> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-parallel-read-in-order-multi-part.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> Represents the dictionary of a text index in a MergeTree table. It can be used for introspection.

# mergeTreeTextIndex

Represents the dictionary of a text index in MergeTree tables.
Returns tokens with their posting list metadata.
It can be used for introspection.

<h2 id="syntax">
  Syntax
</h2>

```sql theme={null}
mergeTreeTextIndex(database, table, index_name)
```

<h2 id="arguments">
  Arguments
</h2>

| Argument | Description |
| - | - |
| `database` | The database name to read text index from. |
| `table` | The table name to read text index from. |
| `index_name` | The text index to read from. |

<h2 id="returned-value">
  Returned value
</h2>

A table object with tokens and their posting list metadata.

If the index uses the `keyValuePairs` tokenizer, each token is a `(key, value)` pair of a `Map` column, and the result has two additional columns `token_key` and `token_value` with the decoded parts of the token.

<h2 id="usage-example">
  Usage Example
</h2>

```sql title="Query" theme={null}
CREATE TABLE tab
(
    id UInt64,
    s String,
    INDEX idx_s (s) TYPE text(tokenizer = splitByNonAlpha)
)
ENGINE = MergeTree
ORDER BY id;

INSERT INTO tab SELECT number, concatWithSeparator(' ', 'apple', 'banana') FROM numbers(500);
INSERT INTO tab SELECT 500 + number, concatWithSeparator(' ', 'cherry', 'date') FROM numbers(500);

SELECT * FROM mergeTreeTextIndex(currentDatabase(), tab, idx_s);
```

```text title="Response" theme={null}
   ┌─part_name─┬─token──┬─dictionary_compression─┬─cardinality─┬─num_posting_blocks─┬─has_embedded_postings─┬─has_raw_postings─┬─has_compressed_postings─┐
1. │ all_1_1_0 │ apple  │ front_coded            │         500 │                  1 │                     0 │                0 │                       0 │
2. │ all_1_1_0 │ banana │ front_coded            │         500 │                  1 │                     0 │                0 │                       0 │
3. │ all_2_2_0 │ cherry │ front_coded            │         500 │                  1 │                     0 │                0 │                       0 │
4. │ all_2_2_0 │ date   │ front_coded            │         500 │                  1 │                     0 │                0 │                       0 │
   └───────────┴────────┴────────────────────────┴─────────────┴────────────────────┴───────────────────────┴──────────────────┴─────────────────────────┘
```