mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-12-11 00:42:29 +00:00
54 lines
1.8 KiB
MySQL
54 lines
1.8 KiB
MySQL
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DROP TABLE IF EXISTS t_sparse_detach;
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CREATE TABLE t_sparse_detach(id UInt64, s String)
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ENGINE = MergeTree ORDER BY id
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SETTINGS ratio_of_defaults_for_sparse_serialization = 0.9;
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INSERT INTO t_sparse_detach SELECT number, number % 20 = 0 ? toString(number) : '' FROM numbers(10000);
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INSERT INTO t_sparse_detach SELECT number, number % 20 = 0 ? toString(number) : '' FROM numbers(10000);
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OPTIMIZE TABLE t_sparse_detach FINAL;
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SELECT count() FROM t_sparse_detach WHERE s != '';
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SELECT column, serialization_kind FROM system.parts_columns
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WHERE table = 't_sparse_detach' AND database = currentDatabase() AND active
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ORDER BY column;
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DETACH TABLE t_sparse_detach;
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ATTACH TABLE t_sparse_detach;
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SELECT count() FROM t_sparse_detach WHERE s != '';
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SELECT column, serialization_kind FROM system.parts_columns
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WHERE table = 't_sparse_detach' AND database = currentDatabase() AND active
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ORDER BY column;
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TRUNCATE TABLE t_sparse_detach;
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ALTER TABLE t_sparse_detach
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MODIFY SETTING vertical_merge_algorithm_min_rows_to_activate = 1,
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vertical_merge_algorithm_min_columns_to_activate = 1;
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INSERT INTO t_sparse_detach SELECT number, number % 20 = 0 ? toString(number) : '' FROM numbers(10000);
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INSERT INTO t_sparse_detach SELECT number, number % 20 = 0 ? toString(number) : '' FROM numbers(10000);
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OPTIMIZE TABLE t_sparse_detach FINAL;
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SELECT count() FROM t_sparse_detach WHERE s != '';
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SELECT column, serialization_kind FROM system.parts_columns
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WHERE table = 't_sparse_detach' AND database = currentDatabase() AND active
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ORDER BY column;
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DETACH TABLE t_sparse_detach;
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ATTACH TABLE t_sparse_detach;
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SELECT count() FROM t_sparse_detach WHERE s != '';
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SELECT column, serialization_kind FROM system.parts_columns
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WHERE table = 't_sparse_detach' AND database = currentDatabase() AND active
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ORDER BY column;
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DROP TABLE t_sparse_detach;
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