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/**
* Tests that the lookup metrics are recorded correctly in serverStatus.
*/
(function() {
"use strict";
load("jstests/libs/sbe_util.js"); // For 'checkSBEEnabled()'.
load("jstests/libs/analyze_plan.js"); // For 'getAggPlanStages' and other explain helpers.
const conn =
MongoRunner.runMongod({setParameter: {featureFlagSbeFull: true, allowDiskUseByDefault: true}});
assert.neq(null, conn, "mongod was unable to start up");
const db = conn.getDB(jsTestName());
if (!checkSBEEnabled(db)) {
jsTestLog("Skipping test because either the sbe lookup pushdown feature flag is disabled or" +
" sbe itself is disabled");
MongoRunner.stopMongod(conn);
return;
}
assert.commandWorked(db.dropDatabase());
// Set up the database.
assert.commandWorked(db.students.insertMany([
{sID: 22001, name: "Alex", year: 1, score: 4.0},
{sID: 21001, name: "Bernie", year: 2, score: 3.7},
{sID: 20010, name: "Chris", year: 3, score: 2.5},
{sID: 22021, name: "Drew", year: 1, score: 3.2},
{sID: 17301, name: "Harley", year: 6, score: 3.1},
{sID: 21022, name: "Farmer", year: 1, score: 2.2},
{sID: 20020, name: "George", year: 3, score: 2.8},
{sID: 18020, name: "Harley", year: 5, score: 2.8},
]));
assert.commandWorked(db.createView("firstYears", "students", [{$match: {year: 1}}]));
assert.commandWorked(db.people.insertMany([
{pID: 1000, name: "Alex"},
{pID: 1001, name: "Drew"},
{pID: 1002, name: "Justin"},
{pID: 1003, name: "Parker"},
]));
const lookupStrategy = {
nestedLoopJoin: "nestedLoopJoin",
indexedLoopJoin: "indexedLoopJoin",
hashLookup: "hashLookup",
nonSbe: "nonSbe"
};
// Create an object with the correct lookup counter values after the specified type of query.
function generateExpectedCounters(joinStrategy = lookupStrategy.nonSbe, spillToDisk = 0) {
let counters = db.serverStatus().metrics.query.lookup;
assert(counters, "counters did not exist");
let expected = Object.assign(counters);
expected.pipelineTotalCount = NumberLong(expected.pipelineTotalCount + 1);
let sbeCounters = expected.slotBasedExecutionCounters;
switch (joinStrategy) {
case lookupStrategy.nestedLoopJoin:
sbeCounters.nestedLoopJoin = NumberLong(sbeCounters.nestedLoopJoin + 1);
break;
case lookupStrategy.indexedLoopJoin:
sbeCounters.indexedLoopJoin = NumberLong(sbeCounters.indexedLoopJoin + 1);
break;
case lookupStrategy.hashLookup:
sbeCounters.hashLookup = NumberLong(sbeCounters.hashLookup + 1);
sbeCounters.hashLookupSpillToDisk =
NumberLong(sbeCounters.hashLookupSpillToDisk + spillToDisk);
break;
}
return expected;
}
// Compare the values of the lookup counters to an object that represents the expected values.
function compareLookupCounters(expectedCounters) {
let counters = db.serverStatus().metrics.query.lookup;
assert.docEq(counters, expectedCounters);
}
// Run a lookup pipeline that does not get pushed down to SBE because it's querying against a view.
let expectedCounters = generateExpectedCounters();
assert.eq(
db.people
.aggregate([
{$lookup: {from: "firstYears", localField: "name", foreignField: "name", as: "matches"}}
])
.itcount(),
4 /* Matching results */);
compareLookupCounters(expectedCounters);
// Run a lookup pipeline with a hash lookup that gets pushed down to SBE.
expectedCounters = generateExpectedCounters(lookupStrategy.hashLookup);
assert.eq(
db.people
.aggregate([
{$lookup: {from: "students", localField: "name", foreignField: "name", as: "matches"}}
])
.itcount(),
4 /* Matching results */);
compareLookupCounters(expectedCounters);
// Run a lookup pipeline without disk use so that it will use NLJ.
expectedCounters = generateExpectedCounters(lookupStrategy.nestedLoopJoin);
assert.eq(
db.people
.aggregate(
[{
$lookup: {from: "students", localField: "name", foreignField: "name", as: "matches"}
}],
{allowDiskUse: false})
.itcount(),
4 /* Matching results */);
compareLookupCounters(expectedCounters);
// Create an index for the foreign collection so the query uses INLJ.
assert.commandWorked(db["students"].createIndex({name: 1}));
expectedCounters = generateExpectedCounters(lookupStrategy.indexedLoopJoin);
assert.eq(
db.people
.aggregate([
{$lookup: {from: "students", localField: "name", foreignField: "name", as: "matches"}}
])
.itcount(),
4 /* Matching results */);
compareLookupCounters(expectedCounters);
assert.commandWorked(db["students"].dropIndexes());
// Reduce the threshold for spilling with hash lookup and then run a query that will spill.
assert.commandWorked(db.adminCommand({
setParameter: 1,
internalQuerySlotBasedExecutionHashLookupApproxMemoryUseInBytesBeforeSpill: 1,
}));
expectedCounters = generateExpectedCounters(lookupStrategy.hashLookup,
16 /* 2 spills per foreign collection row */);
assert.eq(
db.people
.aggregate([
{$lookup: {from: "students", localField: "name", foreignField: "name", as: "matches"}}
])
.itcount(),
4 /* Matching results */);
compareLookupCounters(expectedCounters);
MongoRunner.stopMongod(conn);
})();
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