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These settings are available in system.merge_tree_settings and are autogenerated from ClickHouse source.

dead_blobs_to_delay_insert

If the number of blobs pending removal in the dead blobs queues of the table’s disks exceeds the dead_blobs_to_delay_insert value, an INSERT is artificially slowed down (up to max_delay_to_insert). The dead blobs queue belongs to the disk and is shared by all tables on it (including blobs of already dropped tables), so size the threshold for the whole disk rather than a single table.
It is useful when a server fails to clean up blobs quickly enough.
Possible values:
  • Any positive integer.
  • 0 — disabled.

dead_blobs_to_throw_insert

If the number of blobs pending removal in the dead blobs queues of the table’s disks is more than the dead_blobs_to_throw_insert value, INSERT is interrupted with the following error:
“Too many dead blobs in queue (N) on disks of table. Blobs cleanup is processing significantly slower than inserts”
The dead blobs queue belongs to the disk and is shared by all tables on it (including blobs of already dropped tables), so size the threshold for the whole disk rather than a single table. Possible values:
  • Any positive integer.
  • 0 — disabled.
Last modified on July 23, 2026