CREATE TABLE `access_path_selection` ( `a` int, `b` int, KEY `IDX_a` (`a`), KEY `IDX_b` (`b`), KEY `IDX_ab` (`a`, `b`) ); explain select a from access_path_selection where a < 3; id estRows task access object operator info IndexReader_6 3323.33 root index:IndexRangeScan_5 └─IndexRangeScan_5 3323.33 cop[tikv] table:access_path_selection, index:IDX_a(a) range:[-inf,3), keep order:false, stats:pseudo explain select a, b from access_path_selection where a < 3; id estRows task access object operator info IndexReader_6 3323.33 root index:IndexRangeScan_5 └─IndexRangeScan_5 3323.33 cop[tikv] table:access_path_selection, index:IDX_ab(a, b) range:[-inf,3), keep order:false, stats:pseudo explain select a, b from access_path_selection where b < 3; id estRows task access object operator info TableReader_7 3323.33 root data:Selection_6 └─Selection_6 3323.33 cop[tikv] lt(test.access_path_selection.b, 3) └─TableFullScan_5 10000.00 cop[tikv] table:access_path_selection keep order:false, stats:pseudo explain select a, b from access_path_selection where a < 3 and b < 3; id estRows task access object operator info IndexReader_11 1104.45 root index:Selection_10 └─Selection_10 1104.45 cop[tikv] lt(test.access_path_selection.b, 3) └─IndexRangeScan_9 3323.33 cop[tikv] table:access_path_selection, index:IDX_ab(a, b) range:[-inf,3), keep order:false, stats:pseudo explain select a, b from access_path_selection where a > 10 order by _tidb_rowid; id estRows task access object operator info Projection_6 3333.33 root test.access_path_selection.a, test.access_path_selection.b └─TableReader_13 3333.33 root data:Selection_12 └─Selection_12 3333.33 cop[tikv] gt(test.access_path_selection.a, 10) └─TableFullScan_11 10000.00 cop[tikv] table:access_path_selection keep order:true, stats:pseudo explain select max(_tidb_rowid) from access_path_selection; id estRows task access object operator info StreamAgg_13 1.00 root funcs:max(test.access_path_selection._tidb_rowid)->Column#4 └─Limit_17 1.00 root offset:0, count:1 └─TableReader_27 1.00 root data:Limit_26 └─Limit_26 1.00 cop[tikv] offset:0, count:1 └─TableFullScan_25 1.25 cop[tikv] table:access_path_selection keep order:true, desc, stats:pseudo explain select count(1) from access_path_selection; id estRows task access object operator info StreamAgg_28 1.00 root funcs:count(Column#18)->Column#4 └─TableReader_29 1.00 root data:StreamAgg_8 └─StreamAgg_8 1.00 cop[tikv] funcs:count(1)->Column#18 └─TableFullScan_24 10000.00 cop[tikv] table:access_path_selection keep order:false, stats:pseudo