Skip to content
ClickHouse Docs
49.6kGet Started

alter_* session settings

View as MarkdownEdit this pageReport an issueSet up docs MCP

Autogenerated from ClickHouse system tables

These settings are available in system.settings and are autogenerated from the ClickHouse snapshot.

alter_move_to_space_execute_async

TypeBoolDefault0

Execute ALTER TABLE MOVE … TO [DISK|VOLUME] asynchronously

alter_partition_verbose_result

TypeBoolDefault0

Enables or disables the display of information about the parts to which the manipulation operations with partitions and parts have been successfully applied. Applicable to ATTACH PARTITION|PART and to FREEZE PARTITION.

Possible values:

  • 0 — disable verbosity.
  • 1 — enable verbosity.

Example

CREATE TABLE test(a Int64, d Date, s String) ENGINE = MergeTree PARTITION BY toYYYYMDECLARE(d) ORDER BY a;
INSERT INTO test VALUES(1, '2021-01-01', '');
INSERT INTO test VALUES(1, '2021-01-01', '');
ALTER TABLE test DETACH PARTITION ID '202101';

ALTER TABLE test ATTACH PARTITION ID '202101' SETTINGS alter_partition_verbose_result = 1;

┌─command_type─────┬─partition_id─┬─part_name────┬─old_part_name─┐
│ ATTACH PARTITION │ 202101       │ 202101_7_7_0 │ 202101_5_5_0  │
│ ATTACH PARTITION │ 202101       │ 202101_8_8_0 │ 202101_6_6_0  │
└──────────────────┴──────────────┴──────────────┴───────────────┘

ALTER TABLE test FREEZE SETTINGS alter_partition_verbose_result = 1;

┌─command_type─┬─partition_id─┬─part_name────┬─backup_name─┬─backup_path───────────────────┬─part_backup_path────────────────────────────────────────────┐
│ FREEZE ALL   │ 202101       │ 202101_7_7_0 │ 8           │ /var/lib/clickhouse/shadow/8/ │ /var/lib/clickhouse/shadow/8/data/default/test/202101_7_7_0 │
│ FREEZE ALL   │ 202101       │ 202101_8_8_0 │ 8           │ /var/lib/clickhouse/shadow/8/ │ /var/lib/clickhouse/shadow/8/data/default/test/202101_8_8_0 │
└──────────────┴──────────────┴──────────────┴─────────────┴───────────────────────────────┴─────────────────────────────────────────────────────────────┘

alter_sync

TypeUInt64Default1

Allows you to specify how ALTER, OPTIMIZE, or TRUNCATE queries wait for their operations to complete.

Possible values:

  • 0 — Do not wait.
  • 1 — Wait for own execution.
  • 2 — Wait for everyone.
  • 3 - Only wait for active replicas. Inactive replicas apply the change when they become active.

Cloud default value: 0.

alter_update_mode

TypeAlterUpdateModeDefaultheavy

A mode for ALTER queries that have the UPDATE commands.

Possible values:

  • heavy - run regular mutation.
  • lightweight - run lightweight update if possible, run regular mutation otherwise.
  • lightweight_force - run lightweight update if possible, throw otherwise.
Navigation