M(SettingUInt64,min_compress_block_size,65536,"The actual size of the block to compress, if the uncompressed data less than max_compress_block_size is no less than this value and no less than the volume of data for one mark.") \
M(SettingUInt64,max_compress_block_size,1048576,"The maximum size of blocks of uncompressed data before compressing for writing to a table.") \
M(SettingUInt64,max_block_size,DEFAULT_BLOCK_SIZE,"Maximum block size for reading") \
M(SettingUInt64,max_insert_block_size,DEFAULT_INSERT_BLOCK_SIZE,"The maximum block size for insertion, if we control the creation of blocks for insertion.") \
M(SettingUInt64,min_insert_block_size_rows,DEFAULT_INSERT_BLOCK_SIZE,"Squash blocks passed to INSERT query to specified size in rows, if blocks are not big enough.") \
M(SettingUInt64,min_insert_block_size_bytes,(DEFAULT_INSERT_BLOCK_SIZE*256),"Squash blocks passed to INSERT query to specified size in bytes, if blocks are not big enough.") \
M(SettingMaxThreads,max_threads,0,"The maximum number of threads to execute the request. By default, it is determined automatically.") \
M(SettingUInt64,max_read_buffer_size,DBMS_DEFAULT_BUFFER_SIZE,"The maximum size of the buffer to read from the filesystem.") \
M(SettingUInt64,max_distributed_connections,1024,"The maximum number of connections for distributed processing of one query (should be greater than max_threads).") \
M(SettingUInt64,max_query_size,262144,"Which part of the query can be read into RAM for parsing (the remaining data for INSERT, if any, is read later)") \
M(SettingUInt64,interactive_delay,100000,"The interval in microseconds to check if the request is cancelled, and to send progress info.") \
M(SettingSeconds,connect_timeout,DBMS_DEFAULT_CONNECT_TIMEOUT_SEC,"Connection timeout if there are no replicas.") \
M(SettingMilliseconds,connect_timeout_with_failover_ms,DBMS_DEFAULT_CONNECT_TIMEOUT_WITH_FAILOVER_MS,"Connection timeout for selecting first healthy replica.") \
M(SettingUInt64,distributed_connections_pool_size,DBMS_DEFAULT_DISTRIBUTED_CONNECTIONS_POOL_SIZE,"Maximum number of connections with one remote server in the pool.") \
M(SettingUInt64,connections_with_failover_max_tries,DBMS_CONNECTION_POOL_WITH_FAILOVER_DEFAULT_MAX_TRIES,"The maximum number of attempts to connect to replicas.") \
M(SettingBool,extremes,false,"Calculate minimums and maximums of the result columns. They can be output in JSON-formats.") \
M(SettingBool,use_uncompressed_cache,true,"Whether to use the cache of uncompressed blocks.") \
M(SettingBool,replace_running_query,false,"Whether the running request should be canceled with the same id as the new one.") \
M(SettingUInt64,background_pool_size,16,"Number of threads performing background work for tables (for example, merging in merge tree). Only has meaning at server startup.") \
M(SettingUInt64,background_schedule_pool_size,16,"Number of threads performing background tasks for replicated tables. Only has meaning at server startup.") \
M(SettingMilliseconds,distributed_directory_monitor_sleep_time_ms,100,"Sleep time for StorageDistributed DirectoryMonitors in case there is no work or exception has been thrown.") \
M(SettingUInt64,replication_alter_partitions_sync,1,"Wait for actions to manipulate the partitions. 0 - do not wait, 1 - wait for execution only of itself, 2 - wait for everyone.") \
M(SettingUInt64,replication_alter_columns_timeout,60,"Wait for actions to change the table structure within the specified number of seconds. 0 - wait unlimited time.") \
M(SettingLoadBalancing,load_balancing,LoadBalancing::RANDOM,"Which replicas (among healthy replicas) to preferably send a query to (on the first attempt) for distributed processing.") \
M(SettingTotalsMode,totals_mode,TotalsMode::AFTER_HAVING_EXCLUSIVE,"How to calculate TOTALS when HAVING is present, as well as when max_rows_to_group_by and group_by_overflow_mode = ‘any’ are present.") \
M(SettingFloat,totals_auto_threshold,0.5,"The threshold for totals_mode = 'auto'.") \
M(SettingUInt64,group_by_two_level_threshold_bytes,100000000,"From what size of the aggregation state in bytes, a two-level aggregation begins to be used. 0 - the threshold is not set. Two-level aggregation is used when at least one of the thresholds is triggered.") \
M(SettingBool,distributed_aggregation_memory_efficient,false,"Is the memory-saving mode of distributed aggregation enabled.") \
M(SettingUInt64,aggregation_memory_efficient_merge_threads,0,"Number of threads to use for merge intermediate aggregation results in memory efficient mode. When bigger, then more memory is consumed. 0 means - same as 'max_threads'.") \
M(SettingUInt64,max_parallel_replicas,1,"The maximum number of replicas of each shard used when the query is executed. For consistency (to get different parts of the same partition), this option only works for the specified sampling key. The lag of the replicas is not controlled.") \
M(SettingBool,distributed_group_by_no_merge,false,"Do not merge aggregation states from different servers for distributed query processing - in case it is for certain that there are different keys on different shards.") \
M(SettingBool,optimize_skip_unused_shards,false,"Assumes that data is distributed by sharding_key. Optimization to skip unused shards if SELECT query filters by sharding_key.") \
M(SettingUInt64,merge_tree_min_rows_for_concurrent_read,(20*8192),"If at least as many lines are read from one file, the reading can be parallelized.") \
M(SettingUInt64,merge_tree_min_rows_for_seek,0,"You can skip reading more than that number of rows at the price of one seek per file.") \
M(SettingUInt64,merge_tree_coarse_index_granularity,8,"If the index segment can contain the required keys, divide it into as many parts and recursively check them.") \
M(SettingUInt64,merge_tree_max_rows_to_use_cache,(1024*1024),"The maximum number of rows per request, to use the cache of uncompressed data. If the request is large, the cache is not used. (For large queries not to flush out the cache.)") \
M(SettingBool,merge_tree_uniform_read_distribution,true,"Distribute read from MergeTree over threads evenly, ensuring stable average execution time of each thread within one read operation.") \
M(SettingUInt64,optimize_min_equality_disjunction_chain_length,3,"The minimum length of the expression `expr = x1 OR ... expr = xN` for optimization ") \
M(SettingUInt64,mark_cache_min_lifetime,10000,"If the maximum size of mark_cache is exceeded, delete only records older than mark_cache_min_lifetime seconds.") \
M(SettingFloat,max_streams_to_max_threads_ratio,1,"Allows you to use more sources than the number of threads - to more evenly distribute work across threads. It is assumed that this is a temporary solution, since it will be possible in the future to make the number of sources equal to the number of threads, but for each source to dynamically select available work for itself.") \
M(SettingUInt64,log_queries_cut_to_length,100000,"If query length is greater than specified threshold (in bytes), then cut query when writing to query log. Also limit length of printed query in ordinary text log.") \
M(SettingDistributedProductMode,distributed_product_mode,DistributedProductMode::DENY,"How are distributed subqueries performed inside IN or JOIN sections?") \
M(SettingBool,insert_deduplicate,true,"For INSERT queries in the replicated table, specifies that deduplication of insertings blocks should be preformed") \
M(SettingBool,insert_sample_with_metadata,false,"For INSERT queries, specifies that the server need to send metadata about column defaults to the client. This will be used to calculate default expressions.") \
M(SettingUInt64,insert_quorum,0,"For INSERT queries in the replicated table, wait writing for the specified number of replicas and linearize the addition of the data. 0 - disabled.") \
M(SettingUInt64,select_sequential_consistency,0,"For SELECT queries from the replicated table, throw an exception if the replica does not have a chunk written with the quorum; do not read the parts that have not yet been written with the quorum.") \
M(SettingUInt64,table_function_remote_max_addresses,1000,"The maximum number of different shards and the maximum number of replicas of one shard in the `remote` function.") \
M(SettingMilliseconds,read_backoff_min_latency_ms,1000,"Setting to reduce the number of threads in case of slow reads. Pay attention only to reads that took at least that much time.") \
M(SettingUInt64,read_backoff_max_throughput,1048576,"Settings to reduce the number of threads in case of slow reads. Count events when the read bandwidth is less than that many bytes per second.") \
M(SettingMilliseconds,read_backoff_min_interval_between_events_ms,1000,"Settings to reduce the number of threads in case of slow reads. Do not pay attention to the event, if the previous one has passed less than a certain amount of time.") \
M(SettingUInt64,read_backoff_min_events,2,"Settings to reduce the number of threads in case of slow reads. The number of events after which the number of threads will be reduced.") \
M(SettingFloat,memory_tracker_fault_probability,0.,"For testing of `exception safety` - throw an exception every time you allocate memory with the specified probability.") \
M(SettingBool,enable_http_compression,0,"Compress the result if the client over HTTP said that it understands data compressed by gzip or deflate.") \
M(SettingInt64,http_zlib_compression_level,3,"Compression level - used if the client on HTTP said that it understands data compressed by gzip or deflate.") \
M(SettingBool,http_native_compression_disable_checksumming_on_decompress,0,"If you uncompress the POST data from the client compressed by the native format, do not check the checksum.") \
M(SettingBool,input_format_values_interpret_expressions,true,"For Values format: if field could not be parsed by streaming parser, run SQL parser and try to interpret it as SQL expression.") \
M(SettingBool,output_format_json_escape_forward_slashes,true,"Controls escaping forward slashes for string outputs in JSON output format. This is intended for compatibility with JavaScript. Don't confuse with backslashes that are always escaped.") \
M(SettingBool,send_progress_in_http_headers,false,"Send progress notifications using X-ClickHouse-Progress headers. Some clients do not support high amount of HTTP headers (Python requests in particular), so it is disabled by default.") \
M(SettingUInt64,http_headers_progress_interval_ms,100,"Do not send HTTP headers X-ClickHouse-Progress more frequently than at each specified interval.") \
M(SettingBool,fsync_metadata,1,"Do fsync after changing metadata for tables and databases (.sql files). Could be disabled in case of poor latency on server with high load of DDL queries and high load of disk subsystem.") \
\
M(SettingUInt64,input_format_allow_errors_num,0,"Maximum absolute amount of errors while reading text formats (like CSV, TSV). In case of error, if both absolute and relative values are non-zero, and at least absolute or relative amount of errors is lower than corresponding value, will skip until next line and continue.") \
M(SettingFloat,input_format_allow_errors_ratio,0,"Maximum relative amount of errors while reading text formats (like CSV, TSV). In case of error, if both absolute and relative values are non-zero, and at least absolute or relative amount of errors is lower than corresponding value, will skip until next line and continue.") \
M(SettingJoinStrictness,join_default_strictness,JoinStrictness::ALL,"Set default strictness in JOIN query. Possible values: empty string, 'ANY', 'ALL'. If empty, query without strictness will throw exception.") \
M(SettingUInt64,max_replica_delay_for_distributed_queries,300,"If set, distributed queries of Replicated tables will choose servers with replication delay in seconds less than the specified value (not inclusive). Zero means do not take delay into account.") \
M(SettingBool,fallback_to_stale_replicas_for_distributed_queries,1,"Suppose max_replica_delay_for_distributed_queries is set and all replicas for the queried table are stale. If this setting is enabled, the query will be performed anyway, otherwise the error will be reported.") \
M(SettingUInt64,preferred_max_column_in_block_size_bytes,0,"Limit on max column size in block while reading. Helps to decrease cache misses count. Should be close to L2 cache size.") \
M(SettingBool,insert_distributed_sync,false,"If setting is enabled, insert query into distributed waits until data will be sent to all nodes in cluster.") \
M(SettingUInt64,insert_distributed_timeout,0,"Timeout for insert query into distributed. Setting is used only with insert_distributed_sync enabled. Zero value means no timeout.") \
M(SettingBool,optimize_throw_if_noop,false,"If setting is enabled and OPTIMIZE query didn't actually assign a merge then an explanatory exception is thrown") \
M(SettingBool,use_index_for_in_with_subqueries,true,"Try using an index if there is a subquery or a table expression on the right side of the IN operator.") \
M(SettingUInt64,max_rows_to_read,0,"Limit on read rows from the most 'deep' sources. That is, only in the deepest subquery. When reading from a remote server, it is only checked on a remote server.") \
M(SettingUInt64,max_bytes_to_read,0,"Limit on read bytes (after decompression) from the most 'deep' sources. That is, only in the deepest subquery. When reading from a remote server, it is only checked on a remote server.") \
M(SettingOverflowMode<false>,read_overflow_mode,OverflowMode::THROW,"What to do when the limit is exceeded.") \
\
M(SettingUInt64,max_rows_to_group_by,0,"") \
M(SettingOverflowMode<true>,group_by_overflow_mode,OverflowMode::THROW,"What to do when the limit is exceeded.") \
M(SettingUInt64,max_bytes_before_remerge_sort,1000000000,"In case of ORDER BY with LIMIT, when memory usage is higher than specified threshold, perform additional steps of merging blocks before final merge to keep just top LIMIT rows.") \
M(SettingUInt64,max_ast_depth,1000,"Maximum depth of query syntax tree. Checked after parsing.") \
M(SettingUInt64,max_ast_elements,50000,"Maximum size of query syntax tree in number of nodes. Checked after parsing.") \
M(SettingUInt64,max_expanded_ast_elements,500000,"Maximum size of query syntax tree in number of nodes after expansion of aliases and the asterisk.") \
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M(SettingUInt64,readonly,0,"0 - everything is allowed. 1 - only read requests. 2 - only read requests, as well as changing settings, except for the 'readonly' setting.") \
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M(SettingUInt64,max_rows_in_set,0,"Maximum size of the set (in number of elements) resulting from the execution of the IN section.") \
M(SettingUInt64,max_bytes_in_set,0,"Maximum size of the set (in bytes in memory) resulting from the execution of the IN section.") \
M(SettingOverflowMode<false>,set_overflow_mode,OverflowMode::THROW,"What to do when the limit is exceeded.") \
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M(SettingUInt64,max_rows_in_join,0,"Maximum size of the hash table for JOIN (in number of rows).") \
M(SettingUInt64,max_bytes_in_join,0,"Maximum size of the hash table for JOIN (in number of bytes in memory).") \
M(SettingOverflowMode<false>,join_overflow_mode,OverflowMode::THROW,"What to do when the limit is exceeded.") \
M(SettingBool,join_any_take_last_row,false,"When disabled (default) ANY JOIN will take the first found row for a key. When enabled, it will take the last row seen if there are multiple rows for the same key.") \
M(SettingUInt64,max_rows_to_transfer,0,"Maximum size (in rows) of the transmitted external table obtained when the GLOBAL IN/JOIN section is executed.") \
M(SettingUInt64,max_bytes_to_transfer,0,"Maximum size (in uncompressed bytes) of the transmitted external table obtained when the GLOBAL IN/JOIN section is executed.") \
M(SettingOverflowMode<false>,transfer_overflow_mode,OverflowMode::THROW,"What to do when the limit is exceeded.") \
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M(SettingUInt64,max_rows_in_distinct,0,"Maximum number of elements during execution of DISTINCT.") \
M(SettingUInt64,max_bytes_in_distinct,0,"Maximum total size of state (in uncompressed bytes) in memory for the execution of DISTINCT.") \
M(SettingOverflowMode<false>,distinct_overflow_mode,OverflowMode::THROW,"What to do when the limit is exceeded.") \
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M(SettingUInt64,max_memory_usage,0,"Maximum memory usage for processing of single query. Zero means unlimited.") \
M(SettingUInt64,max_memory_usage_for_user,0,"Maximum memory usage for processing all concurrently running queries for the user. Zero means unlimited.") \
M(SettingUInt64,max_memory_usage_for_all_queries,0,"Maximum memory usage for processing all concurrently running queries on the server. Zero means unlimited.") \
M(SettingUInt64,max_network_bandwidth,0,"The maximum speed of data exchange over the network in bytes per second for a query. Zero means unlimited.") \
M(SettingUInt64,max_network_bandwidth_for_user,0,"The maximum speed of data exchange over the network in bytes per second for all concurrently running user queries. Zero means unlimited.")\
M(SettingUInt64,max_network_bandwidth_for_all_users,0,"The maximum speed of data exchange over the network in bytes per second for all concurrently running queries. Zero means unlimited.") \
M(SettingChar,format_csv_delimiter,',',"The character to be considered as a delimiter in CSV data. If setting with a string, a string has to have a length of 1.") \
M(SettingDateTimeInputFormat,date_time_input_format,FormatSettings::DateTimeInputFormat::Basic,"Method to read DateTime from text input formats. Possible values: 'basic' and 'best_effort'.") \
M(SettingBool,log_query_threads,true,"Log query threads into system.query_thread_log table. This setting have effect only when 'log_queries' is true.") \
M(SettingLogsLevel,send_logs_level,"none","Send server text logs with specified minimum level to client. Valid values: 'trace', 'debug', 'information', 'warning', 'error', 'none'") \
M(SettingUInt64,low_cardinality_max_dictionary_size,8192,"Maximum size (in rows) of shared global dictionary for LowCardinality type.") \
M(SettingBool,low_cardinality_use_single_dictionary_for_part,false,"LowCardinality type serialization setting. If is true, than will use additional keys when global dictionary overflows. Otherwise, will create several shared dictionaries.") \
M(SettingBool,prefer_localhost_replica,1,"1 - always send query to local replica, if it exists. 0 - choose replica to send query between local and remote ones according to load_balancing") \
M(SettingUInt64,http_max_multipart_form_data_size,1024*1024*1024,"Limit on size of multipart/form-data content. This setting cannot be parsed from URL parameters and should be set in user profile. Note that content is parsed and external tables are created in memory before start of query execution. And this is the only limit that has effect on that stage (limits on max memory usage and max execution time have no effect while reading HTTP form data).") \
M(SettingBool,calculate_text_stack_trace,1,"Calculate text stack trace in case of exceptions during query execution. This is the default. It requires symbol lookups that may slow down fuzzing tests when huge amount of wrong queries are executed. In normal cases you should not disable this option.") \
M(SettingBool,enable_unaligned_array_join,false,"Allow ARRAY JOIN with multiple arrays that have different sizes. When this settings is enabled, arrays will be resized to the longest one.") \
M(SettingBool,low_cardinality_allow_in_native_format,true,"Use LowCardinality type in Native format. Otherwise, convert LowCardinality columns to ordinary for select query, and convert ordinary columns to required LowCardinality for insert query.") \
