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// @tags: [
// # This test attempts to perform write operations and get index usage statistics using the
// # $indexStats stage. The former operation must be routed to the primary in a replica set,
// # whereas the latter may be routed to a secondary.
// assumes_read_preference_unchanged,
// # Cannot implicitly shard accessed collections because of following errmsg: A single
// # update/delete on a sharded collection must contain an exact match on _id or contain the shard
// # key.
// assumes_unsharded_collection,
// does_not_support_stepdowns,
// requires_non_retryable_writes,
// ]
(function() {
"use strict";
load("jstests/libs/analyze_plan.js");
var colName = "jstests_index_stats";
var col = db[colName];
col.drop();
var getUsageCount = function(indexName, collection) {
collection = collection || col;
var cursor = collection.aggregate([{$indexStats: {}}]);
while (cursor.hasNext()) {
var doc = cursor.next();
if (doc.name === indexName) {
return doc.accesses.ops;
}
}
return undefined;
};
var getIndexKey = function(indexName) {
var cursor = col.aggregate([{$indexStats: {}}]);
while (cursor.hasNext()) {
var doc = cursor.next();
if (doc.name === indexName) {
return doc.key;
}
}
return undefined;
};
var getIndexNamesForWinningPlan = function(explain) {
var indexNameList = [];
var winningStages = getPlanStages(explain.queryPlanner.winningPlan, "IXSCAN");
for (var i = 0; i < winningStages.length; ++i) {
indexNameList.push(winningStages[i].indexName);
}
return indexNameList;
};
assert.commandWorked(col.insert({a: 1, b: 1, c: 1}));
assert.commandWorked(col.insert({a: 2, b: 2, c: 2}));
assert.commandWorked(col.insert({a: 3, b: 3, c: 3}));
//
// Confirm no index stats object exists prior to index creation.
//
col.findOne({a: 1});
assert.eq(undefined, getUsageCount("a_1"));
//
// Create indexes.
//
assert.commandWorked(col.createIndex({a: 1}, {name: "a_1"}));
assert.commandWorked(col.createIndex({b: 1, c: 1}, {name: "b_1_c_1"}));
var countA = 0; // Tracks expected index access for "a_1".
var countB = 0; // Tracks expected index access for "b_1_c_1".
//
// Confirm a stats object exists post index creation (with 0 count).
//
assert.eq(countA, getUsageCount("a_1"));
assert.eq({a: 1}, getIndexKey("a_1"));
//
// Confirm index stats tick on find().
//
col.findOne({a: 1});
countA++;
assert.eq(countA, getUsageCount("a_1"));
//
// Confirm index stats tick on findAndModify() update.
//
var res =
db.runCommand({findAndModify: colName, query: {a: 1}, update: {$set: {d: 1}}, 'new': true});
assert.commandWorked(res);
countA++;
assert.eq(countA, getUsageCount("a_1"));
//
// Confirm index stats tick on findAndModify() delete.
//
res = db.runCommand({findAndModify: colName, query: {a: 2}, remove: true});
assert.commandWorked(res);
countA++;
assert.eq(countA, getUsageCount("a_1"));
assert.commandWorked(col.insert(res.value));
//
// Confirm $and operation ticks indexes for winning plan, but not rejected plans.
//
// We cannot use explain() to determine which indexes would be used for this query, since
// 1) explain() will not bump the access counters
// 2) explain() always runs the multi planner, and the multi planner may choose a different
// index each run. We therefore run the query, and check that only one of the indexes has its
// counter bumped (assuming we never choose an index intersection plan).
const results = col.find({a: 2, b: 2}).itcount();
if (countA + 1 == getUsageCount("a_1")) {
// Plan using index A was chosen. Index B should not have been used (assuming no index
// intersection plans are used).
countA++;
} else {
// Plan using index B was chosen. Index A should not have been used (assuming no index
// intersection plans are used).
assert.eq(++countB, getUsageCount("b_1_c_1"));
}
assert.eq(countA, getUsageCount("a_1"));
assert.eq(countB, getUsageCount("b_1_c_1"));
assert.eq(0, getUsageCount("_id_"));
//
// Confirm index stats tick on distinct().
//
res = db.runCommand({distinct: colName, key: "b", query: {b: 1}});
assert.commandWorked(res);
countB++;
assert.eq(countB, getUsageCount("b_1_c_1"));
//
// Confirm index stats tick on aggregate w/ match.
//
res = db.runCommand({aggregate: colName, pipeline: [{$match: {b: 1}}], cursor: {}});
assert.commandWorked(res);
countB++;
assert.eq(countB, getUsageCount("b_1_c_1"));
//
// Confirm index stats tick on mapReduce with query.
//
res = db.runCommand({
mapReduce: colName,
map: function() {
emit(this.b, this.c);
},
reduce: function(key, val) {
return val;
},
query: {b: 2},
out: {inline: 1}
});
assert.commandWorked(res);
countB++;
assert.eq(countB, getUsageCount("b_1_c_1"));
//
// Confirm index stats tick on update().
//
assert.commandWorked(col.update({a: 2}, {$set: {d: 2}}));
countA++;
assert.eq(countA, getUsageCount("a_1"));
//
// Confirm index stats tick on remove().
//
assert.commandWorked(col.remove({a: 2}));
countA++;
assert.eq(countA, getUsageCount("a_1"));
//
// Confirm multiple index $or operation ticks all involved indexes.
//
col.findOne({$or: [{a: 1}, {b: 1, c: 1}]});
countA++;
countB++;
assert.eq(countA, getUsageCount("a_1"));
assert.eq(countB, getUsageCount("b_1_c_1"));
//
// Confirm index stats object does not exist post index drop.
//
assert.commandWorked(col.dropIndex("b_1_c_1"));
countB = 0;
assert.eq(undefined, getUsageCount("b_1_c_1"));
//
// Confirm index stats object exists with count 0 once index is recreated.
//
assert.commandWorked(col.createIndex({b: 1, c: 1}, {name: "b_1_c_1"}));
assert.eq(countB, getUsageCount("b_1_c_1"));
//
// Confirm that retrieval fails if $indexStats is not in the first pipeline position.
//
assert.throws(function() {
col.aggregate([{$match: {}}, {$indexStats: {}}]);
});
//
// Confirm index use is recorded for $lookup.
//
const foreignCollection = db[colName + "_foreign"];
foreignCollection.drop();
assert.commandWorked(foreignCollection.insert([{_id: 0}, {_id: 1}, {_id: 2}]));
assert(col.drop());
assert.commandWorked(col.insert([{_id: 0, foreignId: 1}, {_id: 1, foreignId: 2}]));
assert.eq(0, getUsageCount("_id_"));
assert.eq(2,
col.aggregate([
{$match: {_id: {$in: [0, 1]}}},
{
$lookup: {
from: foreignCollection.getName(),
localField: 'foreignId',
foreignField: '_id',
as: 'results'
}
}
])
.itcount());
assert.eq(1, getUsageCount("_id_", col), "Expected aggregation to use _id index");
assert.eq(2,
getUsageCount("_id_", foreignCollection),
"Expected each lookup to be tracked as an index use");
//
// Confirm index use is recorded for $graphLookup.
//
foreignCollection.drop();
assert.commandWorked(foreignCollection.insert([
{_id: 0, connectedTo: 1},
{_id: 1, connectedTo: "X"},
{_id: 2, connectedTo: 3},
{_id: 3, connectedTo: "Y"}, // Be sure to use a different value here to make sure
// $graphLookup doesn't cache the query.
]));
assert(col.drop());
assert.commandWorked(col.insert([{_id: 0, foreignId: 0}, {_id: 1, foreignId: 2}]));
assert.eq(0, getUsageCount("_id_"));
assert.eq(2,
col.aggregate([
{$match: {_id: {$in: [0, 1]}}},
{
$graphLookup: {
from: foreignCollection.getName(),
startWith: '$foreignId',
connectToField: '_id',
connectFromField: 'connectedTo',
as: 'results'
}
}
])
.itcount());
assert.eq(1, getUsageCount("_id_", col), "Expected aggregation to use _id index");
assert.eq(2 * 3,
getUsageCount("_id_", foreignCollection),
"Expected each of two graph searches to issue 3 queries, each using the _id index");
//
// Confirm that index 'hidden' status can be found in '$indexStats'.
//
assert(col.drop());
assert.commandWorked(col.createIndex({a: 1}, {hidden: true}));
const hiddenIndexStats =
col.aggregate([{$indexStats: {}}, {$match: {"name": "a_1", "spec.hidden": true}}]).toArray();
assert.eq(hiddenIndexStats.length, 1);
//
// Confirm the index usage stats will be reset on hiding and unhiding the index.
//
assert(col.drop());
assert.commandWorked(col.insert({a: 1}));
assert.commandWorked(col.createIndex({a: 1}));
// When the index is not hidden, the stats keep counting.
res = col.findOne({a: 1});
assert(1, res);
assert.eq(1, getUsageCount("a_1"));
// On modifying an index's definition (i.e. hiding or unhiding an index), the usage stats of the
// index will be reset to zero.
assert.commandWorked(col.hideIndex("a_1"));
assert.eq(0, getUsageCount("a_1"));
// Confirm that the stats don't tick after the index is hidden.
res = col.findOne({a: 1});
assert(1, res);
assert.eq(0, getUsageCount("a_1"));
assert.commandWorked(col.unhideIndex("a_1"));
res = col.findOne({a: 1});
assert(1, res);
assert.eq(1, getUsageCount("a_1"));
})();
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