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791146b9d2
Make the Range Optimizer support descending index key parts. We follow the approach taken in MySQL-8. See HowRangeOptimizerHandlesDescKeyparts for the description.
158 lines
3.6 KiB
Text
158 lines
3.6 KiB
Text
create table t1 (
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a int,
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key (a desc)
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);
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insert into t1 select seq from seq_1_to_1000;
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set optimizer_trace=1;
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explain select * from t1 force index(a) where a in (2, 4, 6);
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range a a 5 NULL 3 Using where; Using index
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select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
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from information_schema.optimizer_trace;
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json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
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[
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[
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"(6) <= (a) <= (6)",
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"(4) <= (a) <= (4)",
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"(2) <= (a) <= (2)"
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]
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]
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set optimizer_trace=default;
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# These should go in reverse order:
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select * from t1 force index(a) where a in (2, 4, 6);
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a
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6
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4
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2
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drop table t1;
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#
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# Multi-part key tests
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#
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create table t1 (
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a int not null,
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b int not null,
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key ab(a, b desc)
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);
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insert into t1 select A.seq, B.seq*10 from seq_1_to_10 A, seq_1_to_10 B;
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set optimizer_trace=1;
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explain select * from t1 force index(ab) where a>=8 and b>=50;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range ab ab 4 NULL 51 Using where; Using index
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select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
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from information_schema.optimizer_trace;
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json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
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[
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[
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"(8) <= (a)"
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]
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]
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explain select * from t1 force index(ab) where a>=8 and b<=50;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range ab ab 8 NULL 46 Using where; Using index
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select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
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from information_schema.optimizer_trace;
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json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
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[
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[
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"(8,50) <= (a,b)"
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]
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]
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select * from t1 force index(ab) where a>=8 and b<=50;
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a b
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8 50
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8 40
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8 30
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8 20
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8 10
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9 50
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9 40
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9 30
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9 20
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9 10
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10 50
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10 40
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10 30
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10 20
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10 10
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select * from t1 ignore index(ab) where a>=8 and b<=50 order by a, b desc;
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a b
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8 50
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8 40
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8 30
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8 20
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8 10
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9 50
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9 40
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9 30
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9 20
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9 10
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10 50
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10 40
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10 30
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10 20
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10 10
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explain
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select * from t1 where a between 2 and 4 and b between 50 and 80;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range ab ab 8 NULL 17 Using where; Using index
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select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
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from information_schema.optimizer_trace;
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json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
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[
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[
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"(2,80) <= (a,b) <= (4,50)"
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]
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]
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select * from t1 where a between 2 and 4 and b between 50 and 80;
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a b
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2 80
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2 70
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2 60
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2 50
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3 80
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3 70
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3 60
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3 50
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4 80
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4 70
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4 60
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4 50
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drop table t1;
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create table t2 (
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a int not null,
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b int not null,
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key ab(a desc, b desc)
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);
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insert into t2 select A.seq, B.seq*10 from seq_1_to_10 A, seq_1_to_10 B;
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explain
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select * from t2 where a between 2 and 4;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 range ab ab 4 NULL 40 Using where; Using index
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select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
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from information_schema.optimizer_trace;
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json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
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[
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[
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"(4) <= (a) <= (2)"
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]
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]
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explain
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select * from t2 where a between 2 and 4 and b between 50 and 80;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 range ab ab 8 NULL 31 Using where; Using index
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select json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
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from information_schema.optimizer_trace;
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json_detailed(json_extract(trace, '$**.range_access_plan.ranges'))
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[
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[
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"(4,80) <= (a,b) <= (2,50)"
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]
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]
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set optimizer_trace=default;
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drop table t2;
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