Important

The SingleStore 9.1 release candidate (RC) gives you the opportunity to preview, evaluate, and provide feedback on new and upcoming features prior to their general availability. In the interim, SingleStore 9.0 is recommended for production workloads, which can later be upgraded to SingleStore 9.1.

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`
`allow_unsupported_filesystem`
`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.
`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.
`character_set_connection`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore.
`character_set_database`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore.
`character_set_filesystem`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore.
`character_set_results`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore.
`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`
`columnar_segment_rows`	Deprecated alias to `columnstore_segment_rows`.
`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.
`datetime_format`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore.
`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_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.
`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.
`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.
`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.
`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_validate_blob_after_write`
`internal_columnstore_validate_blob_before_read`
`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.
`lc_time_names`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore.
`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.
`lock_logging_min_latency`
`lock_upgrade`
`locked_in_memory`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore.
`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.
`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.
`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.
`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.
`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`
`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.
`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.
`tx_read_only`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore.
`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. To check the version of SingleStore 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.
`wait_die_retry_until_timeout_on_die`
`wait_timeout`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore.
`warning_count`	This variable exists for backwards compatibility with MySQL and is non-operational in SingleStore.

Reserved Engine Variables

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