MergeTree tables settings

import ExperimentalBadge from '@theme/badges/ExperimentalBadge'; import BetaBadge from '@theme/badges/BetaBadge'; import SettingsInfoBlock from '@theme/SettingsInfoBlock/SettingsInfoBlock'; import VersionHistory from '@theme/VersionHistory/VersionHistory';

System table system.merge_tree_settings shows the globally set MergeTree settings.

MergeTree settings can be set in the merge_tree section of the server config file, or specified for each MergeTree table individually in the SETTINGS clause of the CREATE TABLE statement.

Example for customizing setting max_suspicious_broken_parts:

Configure the default for all MergeTree tables in the server configuration file:

<merge_tree>
    <max_suspicious_broken_parts>5</max_suspicious_broken_parts>
</merge_tree>

Set for a particular table:

CREATE TABLE tab
(
    `A` Int64
)
ENGINE = MergeTree
ORDER BY tuple()
SETTINGS max_suspicious_broken_parts = 500;

Change the settings for a particular table using ALTER TABLE ... MODIFY SETTING:

ALTER TABLE tab MODIFY SETTING max_suspicious_broken_parts = 100;

-- reset to global default (value from system.merge_tree_settings)
ALTER TABLE tab RESET SETTING max_suspicious_broken_parts;

MergeTree settings {#mergetree-settings}