jstests/core/index/index_check7.js


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// @tags: [
//   assumes_balancer_off,
//   assumes_read_concern_local,
// ]

(function() {
'use strict';

const t = db.index_check7;
t.drop();

assert.commandWorked(t.createIndex({x: 1}));

let docs = [];
for (let i = 0; i < 100; i++) {
    docs.push({_id: i, x: i});
}
assert.commandWorked(t.insert(docs));

let explainResult = t.find({x: 27}).explain(true);
assert.eq(1,
          explainResult.executionStats.totalKeysExamined,
          'explain x=27 with index {x : 1}: ' + tojson(explainResult));

assert.commandWorked(t.createIndex({x: -1}));

explainResult = t.find({x: 27}).explain(true);
assert.eq(1,
          explainResult.executionStats.totalKeysExamined,
          'explain x=27 with indexes {x : 1} and {x: -1}: ' + tojson(explainResult));

explainResult = t.find({x: {$gt: 59}}).explain(true);
assert.eq(40,
          explainResult.executionStats.totalKeysExamined,
          'explain x>59 with indexes {x : 1} and {x: -1}: ' + tojson(explainResult));
})();