ClickHouse/docs/en/operations/system-tables/merge_tree_settings.md
2022-08-28 17:34:50 -04:00

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---
slug: /en/operations/system-tables/merge_tree_settings
title: merge_tree_settings
---
Contains information about settings for `MergeTree` tables.
Columns:
- `name` (String) — Setting name.
- `value` (String) — Setting value.
- `description` (String) — Setting description.
- `type` (String) — Setting type (implementation specific string value).
- `changed` (UInt8) — Whether the setting was explicitly defined in the config or explicitly changed.
**Example**
```sql
:) SELECT * FROM system.merge_tree_settings LIMIT 4 FORMAT Vertical;
```
```text
Row 1:
──────
name: index_granularity
value: 8192
changed: 0
description: How many rows correspond to one primary key value.
type: SettingUInt64
Row 2:
──────
name: min_bytes_for_wide_part
value: 0
changed: 0
description: Minimal uncompressed size in bytes to create part in wide format instead of compact
type: SettingUInt64
Row 3:
──────
name: min_rows_for_wide_part
value: 0
changed: 0
description: Minimal number of rows to create part in wide format instead of compact
type: SettingUInt64
Row 4:
──────
name: merge_max_block_size
value: 8192
changed: 0
description: How many rows in blocks should be formed for merge operations.
type: SettingUInt64
4 rows in set. Elapsed: 0.001 sec.
```
[Original article](https://clickhouse.com/docs/en/operations/system-tables/merge_tree_settings) <!--hide-->