303 lines
13 KiB
Plaintext
303 lines
13 KiB
Plaintext
drop table if exists t;
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create table t (v int);
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explain format = 'brief' select * from t t1, t t2;
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id estRows task access object operator info
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HashJoin 100000000.00 root CARTESIAN inner join
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├─TableReader(Build) 10000.00 root data:TableFullScan
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│ └─TableFullScan 10000.00 cop[tikv] table:t2 keep order:false, stats:pseudo
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└─TableReader(Probe) 10000.00 root data:TableFullScan
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└─TableFullScan 10000.00 cop[tikv] table:t1 keep order:false, stats:pseudo
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explain format = 'brief' select * from t t1 where exists (select 1 from t t2 where t2.v > t1.v);
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id estRows task access object operator info
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HashJoin 7992.00 root CARTESIAN semi join, other cond:gt(executor__explain.t.v, executor__explain.t.v)
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├─TableReader(Build) 9990.00 root data:Selection
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│ └─Selection 9990.00 cop[tikv] not(isnull(executor__explain.t.v))
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│ └─TableFullScan 10000.00 cop[tikv] table:t2 keep order:false, stats:pseudo
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└─TableReader(Probe) 9990.00 root data:Selection
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└─Selection 9990.00 cop[tikv] not(isnull(executor__explain.t.v))
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└─TableFullScan 10000.00 cop[tikv] table:t1 keep order:false, stats:pseudo
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explain format = 'brief' select * from t t1 where exists (select 1 from t t2 where t2.v in (t1.v+1, t1.v+2));
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id estRows task access object operator info
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HashJoin 8000.00 root CARTESIAN semi join, other cond:in(executor__explain.t.v, plus(executor__explain.t.v, 1), plus(executor__explain.t.v, 2))
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├─TableReader(Build) 10000.00 root data:TableFullScan
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│ └─TableFullScan 10000.00 cop[tikv] table:t2 keep order:false, stats:pseudo
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└─TableReader(Probe) 10000.00 root data:TableFullScan
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└─TableFullScan 10000.00 cop[tikv] table:t1 keep order:false, stats:pseudo
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explain format = 'brief' select * from t t1, t t2 where t1.v = t2.v;
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id estRows task access object operator info
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HashJoin 12487.50 root inner join, equal:[eq(executor__explain.t.v, executor__explain.t.v)]
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├─TableReader(Build) 9990.00 root data:Selection
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│ └─Selection 9990.00 cop[tikv] not(isnull(executor__explain.t.v))
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│ └─TableFullScan 10000.00 cop[tikv] table:t2 keep order:false, stats:pseudo
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└─TableReader(Probe) 9990.00 root data:Selection
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└─Selection 9990.00 cop[tikv] not(isnull(executor__explain.t.v))
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└─TableFullScan 10000.00 cop[tikv] table:t1 keep order:false, stats:pseudo
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drop table if exists t;
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create table t (a int);
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explain analyze insert into t select 1;
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select * from t;
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a
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1
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explain analyze update t set a=2 where a=1;
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select * from t;
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a
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2
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explain format = 'brief' insert into t select 1;
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select * from t;
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a
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2
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explain analyze insert into t select 1;
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explain analyze replace into t values (3);
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select * from t order by a;
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a
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1
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2
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3
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desc format='brief' select * from information_schema.statements_summary;
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id estRows task access object operator info
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MemTableScan 10000.00 root table:STATEMENTS_SUMMARY
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desc format='brief' select * from information_schema.statements_summary where digest is null;
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id estRows task access object operator info
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Selection 8000.00 root isnull(Column#5)
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└─MemTableScan 10000.00 root table:STATEMENTS_SUMMARY
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desc format='brief' select * from information_schema.statements_summary where digest = 'abcdefg';
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id estRows task access object operator info
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MemTableScan 10000.00 root table:STATEMENTS_SUMMARY digests: ["abcdefg"]
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desc format='brief' select * from information_schema.statements_summary where digest in ('a','b','c');
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id estRows task access object operator info
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MemTableScan 10000.00 root table:STATEMENTS_SUMMARY digests: ["a","b","c"]
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drop table if exists tt123;
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CREATE TABLE tt123 (
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id int(11) NOT NULL,
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a bigint(20) DEFAULT NULL,
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b char(20) DEFAULT NULL,
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c datetime DEFAULT NULL,
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d double DEFAULT NULL,
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e json DEFAULT NULL,
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f decimal(40,6) DEFAULT NULL,
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PRIMARY KEY (id) /*T![clustered_index] CLUSTERED */,
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KEY a (a),
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KEY b (b),
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KEY c (c),
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KEY d (d),
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KEY f (f)
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) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;
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explain format='brief' select /*+ inl_hash_join(t1) */ * from tt123 t1 join tt123 t2 on t1.b=t2.e;
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id estRows task access object operator info
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Projection 12500.00 root executor__explain.tt123.id, executor__explain.tt123.a, executor__explain.tt123.b, executor__explain.tt123.c, executor__explain.tt123.d, executor__explain.tt123.e, executor__explain.tt123.f, executor__explain.tt123.id, executor__explain.tt123.a, executor__explain.tt123.b, executor__explain.tt123.c, executor__explain.tt123.d, executor__explain.tt123.e, executor__explain.tt123.f
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└─HashJoin 12500.00 root inner join, equal:[eq(executor__explain.tt123.e, Column#15)]
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├─TableReader(Build) 10000.00 root data:TableFullScan
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│ └─TableFullScan 10000.00 cop[tikv] table:t2 keep order:false, stats:pseudo
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└─Projection(Probe) 10000.00 root executor__explain.tt123.id, executor__explain.tt123.a, executor__explain.tt123.b, executor__explain.tt123.c, executor__explain.tt123.d, executor__explain.tt123.e, executor__explain.tt123.f, cast(executor__explain.tt123.b, json BINARY)->Column#15
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└─TableReader 10000.00 root data:TableFullScan
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└─TableFullScan 10000.00 cop[tikv] table:t1 keep order:false, stats:pseudo
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drop table if exists t;
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create table t (a int primary key);
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insert into t values (2);
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set @@tidb_constraint_check_in_place=1;
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explain analyze insert into t values (1), (2), (3);
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Error 1062 (23000): Duplicate entry '2' for key 't.PRIMARY'
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select * from t;
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a
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2
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set @@tidb_constraint_check_in_place=DEFAULT;
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drop table if exists t;
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create table t(a int);
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set @@session.tidb_enable_non_prepared_plan_cache = 1;
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select * from t limit 1;
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a
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select * from t limit 1;
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a
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explain format = 'plan_cache' select * from (select * from t) t1 limit 1;
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id estRows task access object operator info
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Limit_8 1.00 root offset:0, count:1
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└─TableReader_12 1.00 root data:Limit_11
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└─Limit_11 1.00 cop[tikv] offset:0, count:1
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└─TableFullScan_10 1.00 cop[tikv] table:t keep order:false, stats:pseudo
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show warnings;
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Level Code Message
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Warning 1105 skip non-prepared plan-cache: queries that have sub-queries are not supported
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explain format = 'plan_cache' select * from (select * from t) t1 limit 1;
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id estRows task access object operator info
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Limit_8 1.00 root offset:0, count:1
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└─TableReader_12 1.00 root data:Limit_11
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└─Limit_11 1.00 cop[tikv] offset:0, count:1
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└─TableFullScan_10 1.00 cop[tikv] table:t keep order:false, stats:pseudo
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select @@last_plan_from_cache;
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@@last_plan_from_cache
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0
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explain analyze format = 'plan_cache' select * from (select * from t) t1 limit 1;
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show warnings;
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Level Code Message
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Warning 1105 skip non-prepared plan-cache: queries that have sub-queries are not supported
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explain analyze format = 'plan_cache' select * from (select * from t) t1 limit 1;
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select @@last_plan_from_cache;
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@@last_plan_from_cache
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0
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explain format = 'plan_cache' select * from t;
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id estRows task access object operator info
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TableReader_5 10000.00 root data:TableFullScan_4
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└─TableFullScan_4 10000.00 cop[tikv] table:t keep order:false, stats:pseudo
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show warnings;
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Level Code Message
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explain format = 'plan_cache' select * from t;
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id estRows task access object operator info
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TableReader_5 10000.00 root data:TableFullScan_4
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└─TableFullScan_4 10000.00 cop[tikv] table:t keep order:false, stats:pseudo
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select @@last_plan_from_cache;
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@@last_plan_from_cache
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1
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explain analyze format = 'plan_cache' select * from t;
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show warnings;
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Level Code Message
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explain analyze format = 'plan_cache' select * from t;
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select @@last_plan_from_cache;
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@@last_plan_from_cache
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1
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explain select * from t;
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id estRows task access object operator info
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TableReader_5 10000.00 root data:TableFullScan_4
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└─TableFullScan_4 10000.00 cop[tikv] table:t keep order:false, stats:pseudo
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select @@last_plan_from_cache;
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@@last_plan_from_cache
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0
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explain format = 'brief' select * from t;
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id estRows task access object operator info
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TableReader 10000.00 root data:TableFullScan
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└─TableFullScan 10000.00 cop[tikv] table:t keep order:false, stats:pseudo
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select @@last_plan_from_cache;
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@@last_plan_from_cache
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0
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explain format = 'dot' select * from t;
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dot contents
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digraph TableReader_5 {
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subgraph cluster5{
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node [style=filled, color=lightgrey]
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color=black
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label = "root"
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"TableReader_5"
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}
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subgraph cluster4{
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node [style=filled, color=lightgrey]
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color=black
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label = "cop"
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"TableFullScan_4"
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}
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"TableReader_5" -> "TableFullScan_4"
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}
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select @@last_plan_from_cache;
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@@last_plan_from_cache
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0
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explain format = 'hint' select * from t;
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hint
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use_index(@`sel_1` `executor__explain`.`t` )
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select @@last_plan_from_cache;
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@@last_plan_from_cache
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0
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explain format = 'row' select * from t;
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id estRows task access object operator info
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TableReader_5 10000.00 root data:TableFullScan_4
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└─TableFullScan_4 10000.00 cop[tikv] table:t keep order:false, stats:pseudo
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select @@last_plan_from_cache;
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@@last_plan_from_cache
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0
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explain format = 'verbose' select * from t;
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id estRows estCost task access object operator info
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TableReader_5 10000.00 177906.67 root data:TableFullScan_4
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└─TableFullScan_4 10000.00 2035000.00 cop[tikv] table:t keep order:false, stats:pseudo
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select @@last_plan_from_cache;
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@@last_plan_from_cache
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0
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explain format = 'traditional' select * from t;
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id estRows task access object operator info
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TableReader_5 10000.00 root data:TableFullScan_4
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└─TableFullScan_4 10000.00 cop[tikv] table:t keep order:false, stats:pseudo
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select @@last_plan_from_cache;
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@@last_plan_from_cache
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0
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explain format = 'binary' select * from t;
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binary plan
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zQFYCsoBCg1UYWJsZVJlYWRlcl81EncKD1QBEVBGdWxsU2Nhbl80IQEAAAA4DT9BKQABAfBGiMNAOAJAAkoYChYKEWV4ZWN1dG9yX19leHBsYWluEgF0Uh5rZWVwIG9yZGVyOmZhbHNlLCBzdGF0czpwc2V1ZG9w//////8BAwQBeAEGBQEgASFVVVVVlbcFHWYoAUABUhRkYXRhOlQ2kgAAcAUzAQEsAXj///////////8B
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select @@last_plan_from_cache;
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@@last_plan_from_cache
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0
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explain format = 'tidb_json' select * from t;
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TiDB_JSON
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[
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{
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"id": "TableReader_5",
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"estRows": "10000.00",
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"taskType": "root",
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"operatorInfo": "data:TableFullScan_4",
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"subOperators": [
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{
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"id": "TableFullScan_4",
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"estRows": "10000.00",
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"taskType": "cop[tikv]",
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"accessObject": "table:t",
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"operatorInfo": "keep order:false, stats:pseudo"
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}
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]
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}
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]
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select @@last_plan_from_cache;
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@@last_plan_from_cache
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0
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explain format = 'cost_trace' select * from t;
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id estRows estCost costFormula task access object operator info
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TableReader_5 10000.00 177906.67 ((scan(10000*logrowsize(32)*tikv_scan_factor(40.7))) + (net(10000*rowsize(16)*tidb_kv_net_factor(3.96))))/15.00 root data:TableFullScan_4
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└─TableFullScan_4 10000.00 2035000.00 scan(10000*logrowsize(32)*tikv_scan_factor(40.7)) cop[tikv] table:t keep order:false, stats:pseudo
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select @@last_plan_from_cache;
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@@last_plan_from_cache
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0
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set @@session.tidb_enable_non_prepared_plan_cache = DEFAULT;
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drop table if exists t;
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drop view if exists v;
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drop user if exists 'explain'@'%';
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create table t (id int);
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create view v as select * from t;
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create user 'explain'@'%';
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grant select on executor__explain.v to 'explain'@'%';
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show databases;
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Database
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INFORMATION_SCHEMA
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executor__explain
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use executor__explain;
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select * from v;
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id
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explain format = 'brief' select * from v;
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Error 1345 (HY000): EXPLAIN/SHOW can not be issued; lacking privileges for underlying table
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grant show view on executor__explain.v to 'explain'@'%';
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explain format = 'brief' select * from v;
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id estRows task access object operator info
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TableReader 10000.00 root data:TableFullScan
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└─TableFullScan 10000.00 cop[tikv] table:t keep order:false, stats:pseudo
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revoke select on executor__explain.v from 'explain'@'%';
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explain format = 'brief' select * from v;
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Error 1142 (42000): SELECT command denied to user 'explain'@'%' for table 'v'
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create table t1 (i int);
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create table t2 (j int);
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create table t3 (k int, secret int);
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create view v1 as select * from t1;
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create view v2 as select * from v1, t2;
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create view v3 as select k from t3;
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grant select, show view on executor__explain.v2 to 'explain'@'%';
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grant show view on executor__explain.v1 to 'explain'@'%';
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grant select, show view on executor__explain.t3 to 'explain'@'%';
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grant select, show view on executor__explain.v3 to 'explain'@'%';
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explain select * from v1;
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Error 1142 (42000): SELECT command denied to user 'explain'@'%' for table 'v1'
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explain select * from v2;
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Error 1345 (HY000): EXPLAIN/SHOW can not be issued; lacking privileges for underlying table
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explain select * from t3;
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id estRows task access object operator info
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TableReader_5 10000.00 root data:TableFullScan_4
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└─TableFullScan_4 10000.00 cop[tikv] table:t3 keep order:false, stats:pseudo
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explain select * from v3;
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id estRows task access object operator info
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TableReader_7 10000.00 root data:TableFullScan_6
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└─TableFullScan_6 10000.00 cop[tikv] table:t3 keep order:false, stats:pseudo
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