MergeTree tables settings

## shared\_merge\_tree\_interserver\_http\_timeout\_ms[​](#shared_merge_tree_interserver_http_timeout_ms "Direct link to shared_merge_tree_interserver_http_timeout_ms")

Timeouts for interserver HTTP communication. Only available in ClickHouse
Cloud

## shared\_merge\_tree\_leader\_update\_period\_random\_add\_seconds[​](#shared_merge_tree_leader_update_period_random_add_seconds "Direct link to shared_merge_tree_leader_update_period_random_add_seconds")

Add uniformly distributed value from 0 to x seconds to
shared\_merge\_tree\_leader\_update\_period to avoid thundering
herd effect. Only available in ClickHouse Cloud

## shared\_merge\_tree\_leader\_update\_period\_seconds[​](#shared_merge_tree_leader_update_period_seconds "Direct link to shared_merge_tree_leader_update_period_seconds")

Maximum period to recheck leadership for parts update. Only available in
ClickHouse Cloud

## shared\_merge\_tree\_max\_outdated\_parts\_to\_process\_at\_once[​](#shared_merge_tree_max_outdated_parts_to_process_at_once "Direct link to shared_merge_tree_max_outdated_parts_to_process_at_once")

Maximum amount of outdated parts leader will try to confirm for removal at
one HTTP request. Only available in ClickHouse Cloud.

## shared\_merge\_tree\_max\_parts\_update\_backoff\_ms[​](#shared_merge_tree_max_parts_update_backoff_ms "Direct link to shared_merge_tree_max_parts_update_backoff_ms")

Max backoff for parts update. Only available in ClickHouse Cloud

## shared\_merge\_tree\_max\_parts\_update\_leaders\_in\_total[​](#shared_merge_tree_max_parts_update_leaders_in_total "Direct link to shared_merge_tree_max_parts_update_leaders_in_total")

Maximum number of parts update leaders. Only available in ClickHouse Cloud

## shared\_merge\_tree\_max\_parts\_update\_leaders\_per\_az[​](#shared_merge_tree_max_parts_update_leaders_per_az "Direct link to shared_merge_tree_max_parts_update_leaders_per_az")

Maximum number of parts update leaders. Only available in ClickHouse Cloud

## shared\_merge\_tree\_max\_replicas\_for\_parts\_deletion[​](#shared_merge_tree_max_replicas_for_parts_deletion "Direct link to shared_merge_tree_max_replicas_for_parts_deletion")

Max replicas which will participate in parts deletion (killer thread). Only
available in ClickHouse Cloud

## shared\_merge\_tree\_max\_replicas\_to\_merge\_parts\_for\_each\_parts\_range[​](#shared_merge_tree_max_replicas_to_merge_parts_for_each_parts_range "Direct link to shared_merge_tree_max_replicas_to_merge_parts_for_each_parts_range")

Max replicas which will try to assign potentially conflicting merges (allow
to avoid redundant conflicts in merges assignment). 0 means disabled. Only
available in ClickHouse Cloud

## shared\_merge\_tree\_max\_suspicious\_broken\_parts[​](#shared_merge_tree_max_suspicious_broken_parts "Direct link to shared_merge_tree_max_suspicious_broken_parts")

Max broken parts for SMT, if more - deny automatic detach.

## shared\_merge\_tree\_max\_suspicious\_broken\_parts\_bytes[​](#shared_merge_tree_max_suspicious_broken_parts_bytes "Direct link to shared_merge_tree_max_suspicious_broken_parts_bytes")

Max size of all broken parts for SMT, if more - deny automatic detach.

## shared\_merge\_tree\_memo\_ids\_remove\_timeout\_seconds[​](#shared_merge_tree_memo_ids_remove_timeout_seconds "Direct link to shared_merge_tree_memo_ids_remove_timeout_seconds")

How long we store insert memoization ids to avoid wrong actions during
insert retries. Only available in ClickHouse Cloud

## shared\_merge\_tree\_merge\_coordinator\_election\_check\_period\_ms[​](#shared_merge_tree_merge_coordinator_election_check_period_ms "Direct link to shared_merge_tree_merge_coordinator_election_check_period_ms")

Time between runs of merge coordinator election thread

## shared\_merge\_tree\_merge\_coordinator\_factor[​](#shared_merge_tree_merge_coordinator_factor "Direct link to shared_merge_tree_merge_coordinator_factor")

Time changing factor for delay of coordinator thread

## shared\_merge\_tree\_merge\_coordinator\_fetch\_fresh\_metadata\_period\_ms[​](#shared_merge_tree_merge_coordinator_fetch_fresh_metadata_period_ms "Direct link to shared_merge_tree_merge_coordinator_fetch_fresh_metadata_period_ms")

How often merge coordinator should sync with zookeeper to take fresh metadata

## shared\_merge\_tree\_merge\_coordinator\_max\_merge\_request\_size[​](#shared_merge_tree_merge_coordinator_max_merge_request_size "Direct link to shared_merge_tree_merge_coordinator_max_merge_request_size")

Number of merges that coordinator can request from MergerMutator at once

## shared\_merge\_tree\_merge\_coordinator\_max\_period\_ms[​](#shared_merge_tree_merge_coordinator_max_period_ms "Direct link to shared_merge_tree_merge_coordinator_max_period_ms")

Maximum time between runs of merge coordinator thread

## shared\_merge\_tree\_merge\_coordinator\_merges\_prepare\_count[​](#shared_merge_tree_merge_coordinator_merges_prepare_count "Direct link to shared_merge_tree_merge_coordinator_merges_prepare_count")

Number of merge entries that coordinator should prepare and distribute across workers

## shared\_merge\_tree\_merge\_coordinator\_min\_period\_ms[​](#shared_merge_tree_merge_coordinator_min_period_ms "Direct link to shared_merge_tree_merge_coordinator_min_period_ms")

Minimum time between runs of merge coordinator thread

## shared\_merge\_tree\_merge\_worker\_fast\_timeout\_ms[​](#shared_merge_tree_merge_worker_fast_timeout_ms "Direct link to shared_merge_tree_merge_worker_fast_timeout_ms")

Timeout that merge worker thread will use if it is needed to update it's state after immediate action

## shared\_merge\_tree\_merge\_worker\_regular\_timeout\_ms[​](#shared_merge_tree_merge_worker_regular_timeout_ms "Direct link to shared_merge_tree_merge_worker_regular_timeout_ms")

Time between runs of merge worker thread

## shared\_merge\_tree\_outdated\_parts\_group\_size[​](#shared_merge_tree_outdated_parts_group_size "Direct link to shared_merge_tree_outdated_parts_group_size")

How many replicas will be in the same rendezvous hash group for outdated parts cleanup.
Only available in ClickHouse Cloud.

## shared\_merge\_tree\_partitions\_hint\_ratio\_to\_reload\_merge\_pred\_for\_mutations[​](#shared_merge_tree_partitions_hint_ratio_to_reload_merge_pred_for_mutations "Direct link to shared_merge_tree_partitions_hint_ratio_to_reload_merge_pred_for_mutations")

Will reload merge predicate in merge/mutate selecting task when `<candidate partitions for mutations only (partitions that cannot be merged)>/<candidate partitions for mutations>` ratio is higher than the setting. Only available
in ClickHouse Cloud

## shared\_merge\_tree\_parts\_load\_batch\_size[​](#shared_merge_tree_parts_load_batch_size "Direct link to shared_merge_tree_parts_load_batch_size")

Amount of fetch parts metadata jobs to schedule at once. Only available in
ClickHouse Cloud

## shared\_merge\_tree\_postpone\_next\_merge\_for\_locally\_merged\_parts\_ms[​](#shared_merge_tree_postpone_next_merge_for_locally_merged_parts_ms "Direct link to shared_merge_tree_postpone_next_merge_for_locally_merged_parts_ms")

Time to keep a locally merged part without starting a new merge containing
this part. Gives other replicas a chance fetch the part and start this merge.
Only available in ClickHouse Cloud.

## shared\_merge\_tree\_postpone\_next\_merge\_for\_locally\_merged\_parts\_rows\_threshold[​](#shared_merge_tree_postpone_next_merge_for_locally_merged_parts_rows_threshold "Direct link to shared_merge_tree_postpone_next_merge_for_locally_merged_parts_rows_threshold")

Minimum size of part (in rows) to postpone assigning a next merge just after
merging it locally. Only available in ClickHouse Cloud.

## shared\_merge\_tree\_range\_for\_merge\_window\_size[​](#shared_merge_tree_range_for_merge_window_size "Direct link to shared_merge_tree_range_for_merge_window_size")

Time to keep a locally merged part without starting a new merge containing
this part. Gives other replicas a chance fetch the part and start this merge.
Only available in ClickHouse Cloud