Add description to settings and settings changes

src/Core/Settings.h

@@ -705,7 +705,7 @@ class IColumn;
     M(UInt64, max_size_to_preallocate_for_aggregation, 100'000'000, "For how many elements it is allowed to preallocate space in all hash tables in total before aggregation", 0) \
     \
     M(Bool, kafka_disable_num_consumers_limit, false, "Disable limit on kafka_num_consumers that depends on the number of available CPU cores", 0) \
-    M(Bool, allow_experimental_kafka_store_offsets_in_keeper, false, "Allow experimental feature to store Kafka related offsets in Keeper", 0) \
+    M(Bool, allow_experimental_kafka_store_offsets_in_keeper, false, "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", 0) \
     M(Bool, enable_software_prefetch_in_aggregation, true, "Enable use of software prefetch in aggregation", 0) \
     M(Bool, allow_aggregate_partitions_independently, false, "Enable independent aggregation of partitions on separate threads when partition key suits group by key. Beneficial when number of partitions close to number of cores and partitions have roughly the same size", 0) \
     M(Bool, force_aggregate_partitions_independently, false, "Force the use of optimization when it is applicable, but heuristics decided not to use it", 0) \

src/Core/SettingsChangesHistory.h

@@ -95,6 +95,7 @@ static std::map<ClickHouseVersion, SettingsChangesHistory::SettingsChanges> sett
               {"hdfs_ignore_file_doesnt_exist", false, false, "Allow to return 0 rows when the requested files don't exist instead of throwing an exception in HDFS table engine"},
               {"azure_ignore_file_doesnt_exist", false, false, "Allow to return 0 rows when the requested files don't exist instead of throwing an exception in AzureBlobStorage table engine"},
               {"s3_ignore_file_doesnt_exist", false, false, "Allow to return 0 rows when the requested files don't exist instead of throwing an exception in S3 table engine"},
+              {"allow_experimental_kafka_store_offsets_in_keeper", false, false, "Allow the usage of experimental Kafka storage engine that stores the committed offsets in ClickHouse Keeper"},
               }},
     {"24.5", {{"allow_deprecated_error_prone_window_functions", true, false, "Allow usage of deprecated error prone window functions (neighbor, runningAccumulate, runningDifferenceStartingWithFirstValue, runningDifference)"},
               {"allow_experimental_join_condition", false, false, "Support join with inequal conditions which involve columns from both left and right table. e.g. t1.y < t2.y."},

src/Storages/Kafka/KafkaSettings.h

@@ -38,8 +38,8 @@ const auto KAFKA_CONSUMERS_POOL_TTL_MS_MAX = 600'000;
     M(StreamingHandleErrorMode, kafka_handle_error_mode, StreamingHandleErrorMode::DEFAULT, "How to handle errors for Kafka engine. Possible values: default (throw an exception after rabbitmq_skip_broken_messages broken messages), stream (save broken messages and errors in virtual columns _raw_message, _error).", 0) \
     M(Bool, kafka_commit_on_select, false, "Commit messages when select query is made", 0) \
     M(UInt64, kafka_max_rows_per_message, 1, "The maximum number of rows produced in one kafka message for row-based formats.", 0) \
-    M(String, kafka_keeper_path, "", "TODO(antaljanosbenjamin)", 0) \
+    M(String, kafka_keeper_path, "", "The path to the table in ClickHouse Keeper", 0) \
-    M(String, kafka_replica_name, "", "TODO(antaljanosbenjamin)", 0) \
+    M(String, kafka_replica_name, "", "The replica name in ClickHouse Keeper", 0) \
 
 #define OBSOLETE_KAFKA_SETTINGS(M, ALIAS) \
     MAKE_OBSOLETE(M, Char, kafka_row_delimiter, '\0') \