These settings are available in system.settings and are autogenerated from source.
allow_experimental_ai_functions
Enable experimental AI functions (e.g. aiGenerateContent). These functions make external HTTP calls to AI providers.
allow_experimental_analyzer
Aliases: enable_analyzer
Allow the analyzer.
allow_experimental_cleanup_old_data_files_compaction
Allow to clean up old data files during Iceberg compaction.
allow_experimental_codecs
If it is set to true, allow to specify experimental compression codecs (but we don’t have those yet and this option does nothing).
Allow to execute correlated subqueries.
allow_experimental_database_glue_catalog
Aliases: allow_database_glue_catalog
Allow experimental database engine DataLakeCatalog with catalog_type = ‘glue’
Cloud default value: 1.
allow_experimental_database_hms_catalog
Allow experimental database engine DataLakeCatalog with catalog_type = ‘hms’
allow_experimental_database_iceberg
Aliases: allow_database_iceberg
Allow experimental database engine DataLakeCatalog with catalog_type = ‘iceberg’
Cloud default value: 1.
allow_experimental_database_materialized_postgresql
Allow to create database with Engine=MaterializedPostgreSQL(…).
allow_experimental_database_paimon_rest_catalog
Allow experimental database engine DataLakeCatalog with catalog_type = ‘paimon_rest’
allow_experimental_database_unity_catalog
Aliases: allow_database_unity_catalog
Allow experimental database engine DataLakeCatalog with catalog_type = ‘unity’
Cloud default value: 1.
allow_experimental_delta_kernel_rs
Allow experimental delta-kernel-rs implementation.
allow_experimental_delta_lake_writes
Aliases: allow_delta_lake_writes
Enables delta-kernel writes feature.
allow_experimental_eval_table_function
Enable experimental table function eval.
allow_experimental_expire_snapshots
Allow to execute experimental Iceberg command ALTER TABLE ... EXECUTE expire_snapshots.
allow_experimental_funnel_functions
Enable experimental functions for funnel analysis.
allow_experimental_geo_types_in_iceberg
Allow parsing Iceberg geometry and geography field types as ClickHouse Geometry (Variant) type.
allow_experimental_hash_functions
Enable experimental hash functions
allow_experimental_iceberg_compaction
Allow to explicitly use ‘OPTIMIZE’ for iceberg tables.
allow_experimental_join_right_table_sorting
If it is set to true, and the conditions of join_to_sort_minimum_perkey_rows and join_to_sort_maximum_table_rows are met, rerange the right table by key to improve the performance in left or inner hash join.
allow_experimental_json_lazy_type_hints
Enable experimental lazy type hints for JSON type. This feature allows optimizing JSON type conversions by deferring type hint evaluation.
allow_experimental_kafka_offsets_storage_in_keeper
Allow experimental feature to store Kafka related offsets in ClickHouse Keeper. When enabled a ClickHouse Keeper path and replica name can be specified to the Kafka table engine. As a result instead of the regular Kafka engine, a new type of storage engine will be used that stores the committed offsets primarily in ClickHouse Keeper
allow_experimental_kusto_dialect
Enable Kusto Query Language (KQL) - an alternative to SQL.
allow_experimental_materialized_postgresql_table
Allows to use the MaterializedPostgreSQL table engine. Disabled by default, because this feature is experimental
allow_experimental_nlp_functions
Enable experimental functions for natural language processing.
allow_experimental_nullable_tuple_type
Aliases: enable_nullable_tuple_type
Allows creation of Nullable Tuple columns in tables.
This setting does not control whether extracted tuple subcolumns can be Nullable (for example, from Dynamic, Variant, JSON, or Tuple columns).
Use allow_nullable_tuple_in_extracted_subcolumns to control whether extracted tuple subcolumns can be Nullable.
allow_experimental_object_storage_queue_hive_partitioning
Allow to use hive partitioning with S3Queue/AzureQueue engines
allow_experimental_paimon_storage_engine
Allow to create tables with Paimon* table engines.
allow_experimental_parallel_reading_from_replicas
Aliases: enable_parallel_replicas
Use up to max_parallel_replicas the number of replicas from each shard for SELECT query execution. Reading is parallelized and coordinated dynamically. 0 - disabled, 1 - enabled, silently disable them in case of failure, 2 - enabled, throw an exception in case of failure
allow_experimental_polyglot_dialect
Enable polyglot SQL transpiler - transpiles SQL from 30+ dialects (MySQL, PostgreSQL, SQLite, Snowflake, DuckDB, etc.) into ClickHouse SQL.
allow_experimental_prql_dialect
Enable PRQL - an alternative to SQL.
allow_experimental_time_series_aggregate_functions
Aliases: allow_experimental_ts_to_grid_aggregate_function
Experimental timeSeries* aggregate functions for Prometheus-like timeseries resampling, rate, delta calculation.
allow_experimental_time_series_table
Allows creation of tables with the TimeSeries table engine. Possible values:
allow_experimental_unique_key
Allows creation of tables with the UNIQUE KEY clause on MergeTree-family engines.
allow_experimental_url_wildcard_from_index_pages
Allow experimental wildcard expansion for url() and ENGINE = URL from HTTP index pages.
allow_experimental_window_view
Enable WINDOW VIEW. Not mature enough.
allow_experimental_ytsaurus_dictionary_source
Experimental dictionary source for integration with YTsaurus.
allow_experimental_ytsaurus_table_engine
Experimental table engine for integration with YTsaurus.
allow_experimental_ytsaurus_table_function
Experimental table engine for integration with YTsaurus. Last modified on July 24, 2026
