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50 lines
2.0 KiB
SQL
50 lines
2.0 KiB
SQL
drop table if exists xy;
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create table xy(x int, y int) engine MergeTree partition by intHash64(x) % 2 order by y settings index_granularity = 1;
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-- intHash64(0) % 2 = 0
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-- intHash64(2) % 2 = 1
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-- intHash64(8) % 2 = 0
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-- intHash64(9) % 2 = 1
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insert into xy values (0, 2), (2, 3), (8, 4), (9, 5);
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-- Now we have two partitions: 0 and 1, each of which contains 2 values.
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-- minmax index for the first partition is 0 <= x <= 8
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-- minmax index for the second partition is 2 <= x <= 9
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SET max_rows_to_read = 2;
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select * from xy where intHash64(x) % 2 = intHash64(2) % 2;
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-- Equality is another special operator that can be treated as an always monotonic indicator for deterministic functions.
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-- minmax index is not enough.
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select * from xy where x = 8;
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drop table if exists xy;
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-- Test if we provide enough columns to generate a partition value
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drop table if exists xyz;
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create table xyz(x int, y int, z int) engine MergeTree partition by if(toUInt8(x), y, z) order by x settings index_granularity = 1;
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insert into xyz values (1, 2, 3);
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select * from xyz where y = 2;
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drop table if exists xyz;
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-- Test if we obey strict rules when facing NOT contitions
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drop table if exists test;
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create table test(d Date, k Int64, s String) Engine=MergeTree partition by (toYYYYMM(d),k) order by (d, k);
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insert into test values ('2020-01-01', 1, '');
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insert into test values ('2020-01-02', 1, '');
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select * from test where d != '2020-01-01';
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drop table test;
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-- Test if single value partition pruning works correctly for Date = String
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drop table if exists myTable;
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CREATE TABLE myTable (myDay Date, myOrder Int32, someData String) ENGINE = ReplacingMergeTree PARTITION BY floor(toYYYYMMDD(myDay), -1) ORDER BY (myOrder);
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INSERT INTO myTable (myDay, myOrder) VALUES ('2021-01-01', 1);
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INSERT INTO myTable (myDay, myOrder) VALUES ('2021-01-02', 2); // This row should be returned
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INSERT INTO myTable (myDay, myOrder) VALUES ('2021-01-03', 3);
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SELECT * FROM myTable mt WHERE myDay = '2021-01-02';
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drop table myTable;
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