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44 lines
1.9 KiB
SQL
44 lines
1.9 KiB
SQL
-- There is different code path when:
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-- - _state is not requested
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-- - _state is requested
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-- - only _state is requested
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SELECT * FROM system.parts FORMAT Null;
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SELECT *, _state FROM system.parts FORMAT Null;
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SELECT _state FROM system.parts FORMAT Null;
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-- Create one table and see some columns in system.parts
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DROP TABLE IF EXISTS data_01660;
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CREATE TABLE data_01660 (key Int) Engine=MergeTree() ORDER BY key;
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SYSTEM STOP MERGES data_01660;
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-- Empty
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SELECT _state FROM system.parts WHERE database = currentDatabase() AND table = 'data_01660';
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SELECT name, _state FROM system.parts WHERE database = currentDatabase() AND table = 'data_01660';
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SELECT name, active FROM system.parts WHERE database = currentDatabase() AND table = 'data_01660';
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-- Add part and check again
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SELECT '# two parts';
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INSERT INTO data_01660 VALUES (0);
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INSERT INTO data_01660 VALUES (1);
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SELECT _state FROM system.parts WHERE database = currentDatabase() AND table = 'data_01660';
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SELECT name, _state FROM system.parts WHERE database = currentDatabase() AND table = 'data_01660';
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SELECT name, active FROM system.parts WHERE database = currentDatabase() AND table = 'data_01660';
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-- OPTIMIZE to create Outdated parts
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SELECT '# optimize';
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SYSTEM START MERGES data_01660;
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OPTIMIZE TABLE data_01660 FINAL;
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SELECT count(), _state FROM system.parts WHERE database = currentDatabase() AND table = 'data_01660' GROUP BY _state ORDER BY _state;
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-- TRUNCATE does not remove parts instantly
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-- Empty active parts are clearing by async process
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-- Inactive parts are clearing by async process also
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SELECT '# truncate';
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TRUNCATE data_01660;
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SELECT if (count() > 0, 'HAVE PARTS', 'NO PARTS'), _state FROM system.parts WHERE database = currentDatabase() AND table = 'data_01660' GROUP BY _state;
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-- But DROP does
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SELECT '# drop';
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DROP TABLE data_01660;
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SELECT * FROM system.parts WHERE database = currentDatabase() AND table = 'data_01660';
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