jstests/noPassthrough/plan_cache_list_failed_plans.js


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// Confirms the planCacheListPlans output format includes information about failed plans.
(function() {
    "use strict";

    const conn = MongoRunner.runMongod();
    assert.neq(null, conn, "mongod was unable to start up");
    const testDB = conn.getDB("jstests_plan_cache_list_failed_plans");
    const coll = testDB.test;

    coll.drop();

    // Setup the database such that it will generate a failing plan and a succeeding plan.
    const numDocs = 32;
    const smallNumber = 10;
    assert.commandWorked(
        testDB.adminCommand({setParameter: 1, internalQueryExecMaxBlockingSortBytes: smallNumber}));
    for (let i = 0; i < numDocs * 2; ++i)
        assert.commandWorked(coll.insert({a: ((i >= (numDocs * 2) - smallNumber) ? 1 : 0), d: i}));

    // Create the indexes to create competing plans.
    assert.commandWorked(coll.createIndex({a: 1}));
    assert.commandWorked(coll.createIndex({d: 1}));

    // Assert that the find command found documents.
    const key = {query: {a: 1}, sort: {d: 1}, projection: {}};
    assert.eq(smallNumber, coll.find(key.query).sort(key.sort).itcount());
    let res = assert.commandWorked(coll.runCommand("planCacheListPlans", key));

    // There should have been two plans generated.
    assert.eq(res["plans"].length, 2);
    // The second plan should fail.
    assert.eq(res["plans"][1]["reason"]["failed"], true);

    // The failing plan should have a score of 0.
    assert.eq(res["plans"][1]["reason"]["score"], 0);
    MongoRunner.stopMongod(conn);
})();