Important

New database features are no longer connected to engine versions; features are now enabled independently during scheduled update windows, and “major” and “minor” releases no longer exist in Helios. Please visit the release notes to view the latest features available in your database clusters.

Reserved Engine Variables

The following engine variables are currently reserved for internal use only:

Variable Name	Note
`activity_tracking_id`
`aggregator_id`
`allow_point_in_time_attach`
`allow_unsafe_bottomless_commands`
`alter_signal_timeout`
`analyze_batch_size`
`as_aggregator`
`as_leaf`
`attach_force_skip_execution_errors`
`attach_rebalance_delay_seconds`
`auditlogsdir`
`auto_attach`
`auto_increment_increment`
`auto_increment_offset`
`auto_replicate`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`back_log`
`background_statistics_collection_interval`
`background_statistics_collection_threshold`
`backup_signal_timeout`
`binary_serialization`
`bind_address`
`blob_cache_sync_interval`
`bottomless_cloud_debug_tracing`
`bottomless_incremental_autostats_collection_threshold`
`bottomless_storage_location`
`buffered_rows`
`change_count_write_interval`
`character_set_client`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`character_set_connection`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`character_set_database`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`character_set_filesystem`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`character_set_results`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`character_set_system`	The character set used to store identifiers. The value is read-only and always has the value `utf8`.
`clamp_histogram_date_estimates`
`clear_orphan_databases_on_attach`
`cloud_permissions`
`columnstore_disk_insert_threshold`
`columnstore_json_trace_schema`
`columnstore_row_value_table_lock_threshold`
`columnstore_sample_per_partition_limit`
`columnstore_small_blob_combination_threshold`
`command_loop`
`compile_metadata_parallel`
`convert_nonunique_hash_to_skiplist`
`date_format`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`datetime_format`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`datetime_precision_mode`
`deadlock_avoidance_strategy`
`debug`
`debug_mode`
`default_autostats_columnstore_cardinality_mode`
`default_autostats_columnstore_sampling`
`default_autostats_histogram_mode`
`default_autostats_rowstore_cardinality_mode`
`default_columnstore_table_lock_threshold`
`default_max_histogram_buckets`
`default_spill_dependent_outputters`
`default_week_format`
`defaults_file`
`disable_cluster_variables`
`disable_general_logging`
`disable_histogram_estimation`
`disable_sampling_estimation`
`disable_sampling_estimation_with_histograms`
`disable_subquery_merge_with_straight_joins`
`disable_update_delete_distributed_transactions`
`display_full_estimation_stats`
`distributed_connect_timeout`
`distributed_heartbeat_timeout`
`distributed_optimizer_estimated_restricted_search_cost_bound`
`distributed_optimizer_max_join_size`
`distributed_optimizer_min_join_size_run_initial_heuristics`
`distributed_optimizer_nodes`
`distributed_optimizer_old_selectivity_table_threshold`
`distributed_optimizer_run_legacy_heuristic`
`distributed_optimizer_selectivity_fallback_threshold`
`distributed_optimizer_unrestricted_search_threshold`
`distributed_optimizer_verbose`
`div_precision_increment`
`dont_convert_error_rolled_back_xact`
`durability`
`enable_auto_profile`
`enable_background_flusher`	By setting the value of this variable to `0`, the background flusher will not be able to flush to disk which will result in memory pressure. Refer to Configuring the Columnstore to Work Effectively for more information.
`enable_background_merger`
`enable_background_statistics_collection`
`enable_binary_protocol`
`enable_blob_cache_sync_thread`
`enable_bottomless`
`enable_broadcast_left_join`
`enable_distributed_tracing`
`enable_eks_irsa`
`enable_histogram_to_unwrap_literals`
`enable_ir_cache`
`enable_local_shuffle_group_by`
`enable_multipartition_queries`
`enable_resource_pool_security`
`enable_sites`
`enable_skiplist_sampling_for_selectivity`
`enable_sort_on_load`
`end_tags_on_all_databases`
`error_count`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`estimate_zero_rows_when_sampling_data_is_missing`
`exclude_scalar_subselects_from_filters`
`experimental_csi_join_threshold`
`experimental_disable_multipartition_parallel_read`
`expire_root_password`
`explain_joinplan_costs`
`exporter_password`
exporter_path	This variable is deprecated and non-operational.
`exporter_ssl_key_passphrase`
`external_auth_tracing_time_limit`
`external_functions_whitelist`
`external_user`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`failover_initial_grace_interval_seconds`
`failover_maximum_grace_interval_seconds`
`force_bloom_filters`
`force_bushy_joins`
`force_heuristic_rewrites`
`force_table_pushdown`
`foreign_key_checks`
`forward_aggregator_plan_hash`
`general_log_file`
`geo_query_info`
`group_concat_max_len`
`hash_groupby_segment_distinct_values_threshold`
`have_openssl`
`have_query_cache`
`have_ssl`
`heartbeat_max_connection_saturation_timeout_ms`
`heartbeat_minimum_query_per_sec`
`heartbeat_period_ms`
`heartbeat_ping_failure_timeout_s`
`heartbeats_failed_before_node_failure`
`heartbeats_failed_before_reconnect`
`http_api_close_connection_on_user_drop`
`idle_thread_lifetime_seconds`
`ignore_builtin_innodb`
`ignore_insert_into_computed_column`
`init_connect`
`init_memsql_db_only`
`inlist_precision_limit`
`innodb_buffer_pool_size`
`innodb_lock_wait_timeout`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`innodb_strict_mode`
`insecure_accept_any_password_for_all_users`
`interactive_timeout`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`internal_allow_leaf_alters`
`internal_allow_systable_queries`
`internal_autostats_refresh_enabled`
`internal_cluster_replication_provision_timeout_retries`
`internal_columnstore_idle_flush_wait_seconds`
`internal_columnstore_ingest_aggressive_throttle_ms`
`internal_columnstore_max_uncompressed_rowindex_blob_size`
`internal_columnstore_window_minimum_blob_size`
`internal_drop_all_from_plancache_legacy_behavior`
`internal_dump_bitcode_file`
`internal_dump_clean_bitcode_file`
`internal_dump_raw_bitcode_file`
`internal_enable_parallel_query_throttling`
`internal_extra_sync_replication_logging`
`internal_info_schema_show_hidden_tables`
`internal_keepalive_count`
`internal_keepalive_timeout`
`internal_llvm_compile_externally`
`internal_llvm_detect_cpu_features`
`internal_master_flush`
`internal_max_cte_depth`
`internal_minimum_local_size_for_llvm_lifetimes`
`internal_send_prehandshake_packet`
`internal_session_tracelogs_limit`
`internal_set_keepalive_on_connections`
`internal_set_user_timeout_on_connections`
`internal_slave_flush`
`internal_specialize_common_opcodes`
`internal_trace_compile_args`
`interp_first_auto_gen_helper`
`interpreter_mode_sampling_threshold`
`join_buffer_size`
`json_agg_max_len`
`lc_messages`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`lc_time_names`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`leaf_pushdown_default`
`leaf_pushdown_enable_rowcount`
`license`
`license_visibility`
`llvm_diagnostic_info`
`local_file_system_access_restricted`
`local_infile`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`lock_logging_min_latency`
`lock_upgrade`
`locked_in_memory`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`log_error`
`log_error_verbosity`
`log_output`
`log_queries_not_using_indexes`
`log_warnings`
`lower_case_table_names`
`materialize_ctes`
`max_broadcast_tree_rowcount`
`max_complex_type_elim_rowcount`
`max_connect_errors`
`max_error_count`
`max_heap_table_size`
`max_join_size`
`max_length_for_sort_data`
`max_recursive_cte_iterations`
`max_seeks_for_key`
`max_sort_length`
`max_subselect_aggregator_rowcount`
`max_user_connections`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`max_xact_cache_size_aggs`
`max_xact_cache_size_leaves`
`mbcc_phase_times`
`memsql_custom_build`
`memsql_license`
`minimum_core_count`
`minimum_memory_mb`
`ml_model`
`multi_range_count`
`multistatement_transactions`	This variable is deprecated and its value is ignored started in version 8.5.
`net_retry_count`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`num_workers_background_tasks_pool`
`old`
`old_local_join_optimizer`
`old_passwords`
`openssl_version`
`optimize_constants`
`optimize_expressions_larger_than`
`optimize_huge_expressions`
`optimize_mpl_before_printing`
`optimize_scopes`
`optimize_stmt_threshold`
`optimizer_beam_width`
`optimizer_cross_join_cost`
`optimizer_disable_operator_tree_nullability_check`
`optimizer_disable_right_join`
`optimizer_disable_semi_join_reduction`
`optimizer_disable_subselect_to_join`
`optimizer_empty_tables_limit`
`optimizer_enable_json_text_matching`
`optimizer_gb_placement_table_limit`
`optimizer_hash_join_cost`
`optimizer_latest`
`optimizer_merge_join_cost`
`optimizer_nested_join_cost`
`optimizer_num_partitions`
`optimizer_prune_level`
`optimizer_search_depth`
`optimizer_switch`
`optimizer_warnings`
`password_expiration_seconds`
`password_expiration_mode`
`password_history_count`
`pipelines_extractor_get_offsets_timeout_ms`
`pipelines_extractor_idle_timeout_ms`
`plancachedir`
`port_open_timeout`
`pre_handshake_packet_wait_period_ms`
`preload_buffer_size`
`preserve_original_colstore_json`
`profile_for_debug`
`proxy_user`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`quadratic_rewrite_size_limit`
`query_alloc_block_size`
`query_cache_size`
`query_cache_type`
`query_prealloc_size`
`query_rewrite_loop_iterations`
`read_buffer_size`
`read_only`
`recovery_batch_size`
`ref_repl_mgmt_threads`
`repartition_minimum_buffer_size`
`repl_mgmt_threads`
`replication_sync`	This variable has been deprecated and is no longer operational in SingleStore Helios.
`replication_timeout_ms`
`report_mpl_optimizations`
`reported_hostname`
`reshuffle_group_by_base_cost`
`rewrite_verbose`
`row_lock_conflict_forces_implicit_rollback`
`rows_per_period`
`sampling_estimates_for_complex_filters`
`secure_auth`
`secure_mode`
`selectivity_estimation_min_sample_size`
`service_edition`	An internal configuration item that does not affect the license or features of SingleStore software.
`session_lock`
`set_global_variables_allowed_list`
`singlebox_optimizer_cost_based_threshold`
`skip_blob_crc_checks`
`skip_create_database_resource_check`
`skip_host_cache`
`skip_networking`
`skip_rebalance_blob_cache_warmup`
`skip_rebalance_resource_check`
`skip_show_database`
`slow_launch_time`
`sql_auto_is_null`
`sql_mode`
`sql_notes`
`sql_safe_updates`
`ssl_key_passphrase`
`statistics_warnings`
`strict_mode`
`strict_passwords`
`subquery_merge_with_outer_joins`
`sync2_timeout`
`sync_binlog`
`synchronize_bottomless_timeout_ms`
`synchronize_database_timeout`
`syslog_level`
`syslog_level_CONSENSUS`
`syslog_level_CSI`
`syslog_level_CS_QE`
`syslog_level_LOAD_DATA_INTERNAL_COMPRESSION`
`syslog_level_MCTE`
`syslog_level_METADATA`
`syslog_level_NETWORK`
`syslog_level_PARAMETRIZER`
`syslog_level_REPL`
`syslog_level_SEND_ERROR`
`syslog_level_SPARSE_COMPRESSION`
`syslog_level_TRANSACTIONS`
`syslog_level_WASM`
`syslog_location`
`syslog_protocol`
`target_replica_blob_cache_size_ratio`
`time_format`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`tmp_table_size`
`tmpdir`
`tracelog_level`	When a `tracelog_level_*` variable is set, each component traces to a separate `memsql_$COMPONENT.log` file. Many of these files will be empty and all of them are meant for internal SingleStore use only.
`tracelog_level_CONSENSUS`
`tracelog_level_CSI`
`tracelog_level_CS_QE`
`tracelog_level_LOAD_DATA_INTERNAL_COMPRESSION`
`tracelog_level_MCTE`
`tracelog_level_METADATA`
`tracelog_level_NETWORK`
`tracelog_level_PARAMETRIZER`
`tracelog_level_REPL`
`tracelog_level_SEND_ERROR`
`tracelog_level_SPARSE_COMPRESSION`
`tracelog_level_TRANSACTIONS`
`tracelog_level_WASM`
`tracelogsdir`
`track_leaked_memory`
`transaction_read_only`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`tx_read_only`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`udf_gc_expiry`
`udf_gc_interval`
`unique_checks`
`upgrade_skip_sync_repl_step`
`use_avx2`
`use_bind_address_for_outgoing`
`use_column_correlation`
`use_joincolumnstore`
`use_joincolumnstore_bailout`
`use_joincolumnstore_hash`
`use_joincolumnstore_trace`
`use_memfd_create`
`use_popcnt_instruction`
`use_seekable_json`
`v3_license_path`
`verify_column_compression`
`verify_fields_in_transitivity`
`version`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios. To check the version of SingleStore Helios you are running, use the `memsql_version` variable instead.
`version_comment`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`wait_die_retry_until_timeout_on_die`
`wait_timeout`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.
`warning_count`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore Helios.

Reserved Engine Variables

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