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699291a8e6
- Make the range-et-al optimizer produce E(#table records after table
condition is applied),
- Make the join optimizer use this value,
- Add "filtered" column to EXPLAIN EXTENDED to show
fraction of records left after table condition is applied
- Adjust test results, add comments
11 lines
438 B
Text
11 lines
438 B
Text
drop table if exists t1;
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create table t1(n int not null, key(n)) delay_key_write = 1;
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select count(distinct n) from t1;
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count(distinct n)
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100
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explain extended select count(distinct n) from t1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 index NULL n 4 NULL 200 100.00 Using index
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Warnings:
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Note 1003 select count(distinct `test`.`t1`.`n`) AS `count(distinct n)` from `test`.`t1`
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drop table t1;
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