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Beta and Experimental Features

Because ClickHouse is open-source, it receives many contributions not only from ClickHouse employees but also from the community. These contributions are often developed at different speeds; certain features may require a lengthy prototyping phase or more time for sufficient community feedback and iteration to be considered generally available (GA).

Due to the uncertainty of when features are classified as generally available, we delineate features into two categories: Beta and Experimental.

Beta features are officially supported by the ClickHouse team. Experimental features are early prototypes driven by either the ClickHouse team or the community and are not officially supported.

The sections below explicitly describe the properties of Beta and Experimental features:

Beta Features

  • Under active development to make them generally available (GA)
  • Main known issues can be tracked on GitHub
  • Functionality may change in the future
  • Possibly enabled in ClickHouse Cloud
  • The ClickHouse team supports beta features

The following features are considered Beta in ClickHouse Cloud and are available for use in ClickHouse Cloud Services, even though they may be currently under a ClickHouse SETTING named allow_experimental_*:

Note: please be sure to be using a current version of the ClickHouse compatibility setting to be using a recently introduced feature.

Experimental Features

  • May never become GA
  • May be removed
  • Can introduce breaking changes
  • Functionality may change in the feature
  • Need to be deliberately enabled
  • The ClickHouse team does not support experimental features
  • May lack important functionality and documentation
  • Cannot be enabled in the cloud

Please note: no additional experimental features are allowed to be enabled in ClickHouse Cloud other than those listed above as Beta.

Experimental settings

NameDefault
allow_experimental_replacing_merge_with_cleanup0
allow_experimental_reverse_key0
enable_replacing_merge_with_cleanup_for_min_age_to_force_merge0
force_read_through_cache_for_merges0
merge_selector_algorithmSimple
notify_newest_block_number0
part_moves_between_shards_delay_seconds30
part_moves_between_shards_enable0
remote_fs_zero_copy_path_compatible_mode0
remote_fs_zero_copy_zookeeper_path/clickhouse/zero_copy
remove_rolled_back_parts_immediately1
shared_merge_tree_enable_keeper_parts_extra_data0
allow_experimental_kafka_offsets_storage_in_keeper0
allow_experimental_materialized_postgresql_table0
allow_experimental_funnel_functions0
allow_experimental_nlp_functions0
allow_experimental_hash_functions0
allow_experimental_object_type0
allow_experimental_time_series_table0
allow_experimental_vector_similarity_index0
allow_experimental_codecs0
max_limit_for_ann_queries1000000
hnsw_candidate_list_size_for_search256
throw_on_unsupported_query_inside_transaction1
wait_changes_become_visible_after_commit_modewait_unknown
implicit_transaction0
grace_hash_join_initial_buckets1
grace_hash_join_max_buckets1024
join_to_sort_minimum_perkey_rows40
join_to_sort_maximum_table_rows10000
allow_experimental_join_right_table_sorting0
allow_statistics_optimize0
allow_experimental_statistics0
allow_archive_path_syntax1
allow_experimental_inverted_index0
allow_experimental_full_text_index0
allow_experimental_join_condition0
allow_experimental_live_view0
live_view_heartbeat_interval15
max_live_view_insert_blocks_before_refresh64
allow_experimental_window_view0
window_view_clean_interval60
window_view_heartbeat_interval15
wait_for_window_view_fire_signal_timeout10
stop_refreshable_materialized_views_on_startup0
allow_experimental_database_materialized_postgresql0
allow_experimental_query_deduplication0
allow_experimental_database_iceberg0
allow_experimental_database_unity_catalog0
allow_experimental_database_glue_catalog0
allow_experimental_kusto_dialect0
allow_experimental_prql_dialect0
enable_adaptive_memory_spill_scheduler0
allow_experimental_ts_to_grid_aggregate_function0

Beta settings

NameDefault
allow_remote_fs_zero_copy_replication0
allow_experimental_parallel_reading_from_replicas0
parallel_replicas_moderead_tasks
parallel_replicas_count0
parallel_replica_offset0
parallel_replicas_custom_key``
parallel_replicas_custom_key_range_lower0
parallel_replicas_custom_key_range_upper0
cluster_for_parallel_replicas``
parallel_replicas_allow_in_with_subquery1
parallel_replicas_for_non_replicated_merge_tree0
parallel_replicas_min_number_of_rows_per_replica0
parallel_replicas_prefer_local_join1
parallel_replicas_mark_segment_size0
parallel_replicas_local_plan1
parallel_replicas_index_analysis_only_on_coordinator1
parallel_replicas_only_with_analyzer1
session_timezone``
low_priority_query_wait_time_ms1000