DROP TABLE IF EXISTS lwd_test; CREATE TABLE lwd_test (id UInt64 , value String) ENGINE MergeTree() ORDER BY id; INSERT INTO lwd_test SELECT number, randomString(10) FROM system.numbers LIMIT 1000000; SET mutations_sync = 0; SELECT 'Rows in parts', SUM(rows) FROM system.parts WHERE database = currentDatabase() AND table = 'lwd_test' AND active; SELECT 'Count', count() FROM lwd_test; SELECT 'First row', id, length(value) FROM lwd_test ORDER BY id LIMIT 1; SELECT 'Delete 100K rows using lightweight DELETE'; --ALTER TABLE lwd_test UPDATE _row_exists = 0 WHERE id < 3000000; DELETE FROM lwd_test WHERE id < 100000; SELECT 'Rows in parts', SUM(rows) FROM system.parts WHERE database = currentDatabase() AND table = 'lwd_test' AND active; SELECT 'Count', count() FROM lwd_test; SELECT 'First row', id, length(value) FROM lwd_test ORDER BY id LIMIT 1; SELECT 'Force merge to cleanup deleted rows'; OPTIMIZE TABLE lwd_test FINAL SETTINGS mutations_sync = 2; SELECT 'Rows in parts', SUM(rows) FROM system.parts WHERE database = currentDatabase() AND table = 'lwd_test' AND active; SELECT 'Count', count() FROM lwd_test; SELECT 'First row', id, length(value) FROM lwd_test ORDER BY id LIMIT 1; SELECT 'Delete 100K more rows using lightweight DELETE'; DELETE FROM lwd_test WHERE id < 200000; SELECT 'Rows in parts', SUM(rows) FROM system.parts WHERE database = currentDatabase() AND table = 'lwd_test' AND active; SELECT 'Count', count() FROM lwd_test; SELECT 'First row', id, length(value) FROM lwd_test ORDER BY id LIMIT 1; SELECT 'Do UPDATE mutation'; ALTER TABLE lwd_test UPDATE value = 'v' WHERE id % 2 == 0 SETTINGS mutations_sync = 2; SELECT 'Rows in parts', SUM(rows) FROM system.parts WHERE database = currentDatabase() AND table = 'lwd_test' AND active; SELECT 'Count', count() FROM lwd_test; SELECT 'First row', id, length(value) FROM lwd_test ORDER BY id LIMIT 1; SELECT 'Force merge to cleanup deleted rows'; OPTIMIZE TABLE lwd_test FINAL SETTINGS mutations_sync = 2; SELECT 'Rows in parts', SUM(rows) FROM system.parts WHERE database = currentDatabase() AND table = 'lwd_test' AND active; SELECT 'Count', count() FROM lwd_test; SELECT 'First row', id, length(value) FROM lwd_test ORDER BY id LIMIT 1; SELECT 'Delete 100K more rows using lightweight DELETE'; DELETE FROM lwd_test WHERE id < 300000; SELECT 'Rows in parts', SUM(rows) FROM system.parts WHERE database = currentDatabase() AND table = 'lwd_test' AND active; SELECT 'Count', count() FROM lwd_test; SELECT 'First row', id, length(value) FROM lwd_test ORDER BY id LIMIT 1; SELECT 'Do ALTER DELETE mutation that does a "heavyweight" delete'; ALTER TABLE lwd_test DELETE WHERE id % 3 == 0 SETTINGS mutations_sync = 2; SELECT 'Rows in parts', SUM(rows) FROM system.parts WHERE database = currentDatabase() AND table = 'lwd_test' AND active; SELECT 'Count', count() FROM lwd_test; SELECT 'First row', id, length(value) FROM lwd_test ORDER BY id LIMIT 1; SELECT 'Delete 100K more rows using lightweight DELETE'; DELETE FROM lwd_test WHERE id >= 300000 and id < 400000; SELECT 'Force merge to cleanup deleted rows'; OPTIMIZE TABLE lwd_test FINAL SETTINGS mutations_sync = 2; SELECT 'Rows in parts', SUM(rows) FROM system.parts WHERE database = currentDatabase() AND table = 'lwd_test' AND active; SELECT 'Count', count() FROM lwd_test; SELECT 'First row', id, length(value) FROM lwd_test ORDER BY id LIMIT 1; DROP TABLE lwd_test;