Set up docs MCPThese settings are available in system.merge_tree_settings and are autogenerated from ClickHouse source.
table_disk
Version history
| Version | Default value | Comment |
|---|---|---|
| 25.2 | 0 | New setting |
This is table disk: the path/endpoint points to the table data, not the database data. Supported for object-storage disks whose metadata lives on the object storage itself (s3_plain, s3_plain_rewritable, web, web_index) and their cached variants. Encrypted variants are supported only over the writable s3_plain / s3_plain_rewritable disks, not over the read-only web / web_index disks.
table_readonly
Version history
| Version | Default value | Comment |
|---|---|---|
| 26.3 | 0 | New setting to mark table as read-only, preventing inserts and modifications |
If set to true, the table is in read-only mode and performs no modifications on disk.
All foreground operations that would modify the table are rejected: inserts, mutations, OPTIMIZE, and the data-mutating partition commands
(ATTACH/MOVE/DROP/DROP DETACHED/FETCH/REPLACE PARTITION, as well as MOVE PARTITION ... TO TABLE targeting this table). Operations
that do not modify the table’s data, such as FREEZE/UNFREEZE and FORGET PARTITION, remain allowed.
No background work is scheduled either: regular merges, TTL merges (DELETE/MOVE/recompression), recompression merges, background mutations,
and background part moves are all suppressed. As a consequence, a table with a TTL no longer reclaims or moves its expired data while this setting
is enabled.
The setting can always be toggled back with ALTER TABLE ... MODIFY SETTING table_readonly = 0 (or RESET SETTING). It is not supported for ReplicatedMergeTree.