Using storage policy: s3_cache -- { echo } SYSTEM DROP FILESYSTEM CACHE; SET enable_filesystem_cache_on_write_operations=0; DROP TABLE IF EXISTS test; CREATE TABLE test (key UInt32, value String) Engine=MergeTree() ORDER BY key SETTINGS storage_policy='s3_cache', min_bytes_for_wide_part = 10485760, compress_marks=false, compress_primary_key=false; SYSTEM STOP MERGES test; INSERT INTO test SELECT number, toString(number) FROM numbers(100); SELECT * FROM test FORMAT Null; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache ORDER BY file_segment_range_end, size; 0 79 80 0 745 746 SYSTEM DROP FILESYSTEM CACHE; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache; SELECT * FROM test FORMAT Null; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache; 0 745 746 SYSTEM DROP FILESYSTEM CACHE; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache; DROP TABLE IF EXISTS test; CREATE TABLE test (key UInt32, value String) Engine=MergeTree() ORDER BY key SETTINGS storage_policy='s3_cache_3', min_bytes_for_wide_part = 10485760, compress_marks=false, compress_primary_key=false; INSERT INTO test SELECT number, toString(number) FROM numbers(100); SELECT * FROM test FORMAT Null; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache ORDER BY file_segment_range_end, size; SELECT * FROM test FORMAT Null; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache ORDER BY file_segment_range_end, size; 0 745 746 SYSTEM DROP FILESYSTEM CACHE; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache; SELECT * FROM test FORMAT Null; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache; SYSTEM DROP FILESYSTEM CACHE; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache; Using storage policy: local_cache -- { echo } SYSTEM DROP FILESYSTEM CACHE; SET enable_filesystem_cache_on_write_operations=0; DROP TABLE IF EXISTS test; CREATE TABLE test (key UInt32, value String) Engine=MergeTree() ORDER BY key SETTINGS storage_policy='local_cache', min_bytes_for_wide_part = 10485760, compress_marks=false, compress_primary_key=false; SYSTEM STOP MERGES test; INSERT INTO test SELECT number, toString(number) FROM numbers(100); SELECT * FROM test FORMAT Null; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache ORDER BY file_segment_range_end, size; 0 79 80 0 745 746 SYSTEM DROP FILESYSTEM CACHE; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache; SELECT * FROM test FORMAT Null; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache; 0 745 746 SYSTEM DROP FILESYSTEM CACHE; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache; DROP TABLE IF EXISTS test; CREATE TABLE test (key UInt32, value String) Engine=MergeTree() ORDER BY key SETTINGS storage_policy='local_cache_3', min_bytes_for_wide_part = 10485760, compress_marks=false, compress_primary_key=false; INSERT INTO test SELECT number, toString(number) FROM numbers(100); SELECT * FROM test FORMAT Null; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache ORDER BY file_segment_range_end, size; SELECT * FROM test FORMAT Null; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache ORDER BY file_segment_range_end, size; 0 745 746 SYSTEM DROP FILESYSTEM CACHE; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache; SELECT * FROM test FORMAT Null; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache; SYSTEM DROP FILESYSTEM CACHE; SELECT file_segment_range_begin, file_segment_range_end, size FROM system.filesystem_cache;