allow_experimental_* session settings

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

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_correlated_subqueries

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_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 the Kusto Query Language (KQL) dialect - 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:

• 0 — the TimeSeries table engine is disabled.
• 1 — the TimeSeries table engine is enabled.

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_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.