SET optimize_on_insert = 0; DROP TABLE IF EXISTS replacing_table; CREATE TABLE replacing_table (a UInt32, b UInt32, c UInt32) ENGINE = ReplacingMergeTree ORDER BY a SETTINGS vertical_merge_algorithm_min_rows_to_activate = 1, vertical_merge_algorithm_min_columns_to_activate = 1, index_granularity = 16, min_bytes_for_wide_part = 0, merge_max_block_size = 16; SYSTEM STOP MERGES replacing_table; INSERT INTO replacing_table SELECT number, number, number from numbers(16); INSERT INTO replacing_table SELECT 100, number, number from numbers(16); SELECT sum(a), count() FROM replacing_table; SYSTEM START MERGES replacing_table; OPTIMIZE TABLE replacing_table FINAL; SELECT sum(a), count() FROM replacing_table; DROP TABLE IF EXISTS replacing_table; CREATE TABLE replacing_table ( key UInt64, value UInt64 ) ENGINE = ReplacingMergeTree ORDER BY key SETTINGS vertical_merge_algorithm_min_rows_to_activate=0, vertical_merge_algorithm_min_columns_to_activate=0, min_bytes_for_wide_part = 0; INSERT INTO replacing_table SELECT if(number == 8192, 8191, number), 1 FROM numbers(8193); SELECT sum(key), count() from replacing_table; OPTIMIZE TABLE replacing_table FINAL; SELECT sum(key), count() from replacing_table; DROP TABLE IF EXISTS replacing_table;