// Test oplog queries that can be optimized with oplogReplay.
// @tags: [requires_replication, requires_capped]

(function() {
"use strict";

load("jstests/libs/analyze_plan.js");
load("jstests/libs/storage_engine_utils.js");

const t = db.getSiblingDB("local").oplog.jstests_query_oplogreplay;

function dropOplogAndCreateNew(oplog, newCollectionSpec) {
    if (storageEngineIsWiredTigerOrInMemory()) {
        // We forbid dropping the oplog when using the WiredTiger or in-memory storage engines
        // and so we can't drop the oplog here. Because Evergreen reuses nodes for testing,
        // the oplog may already exist on the test node; in this case, trying to create the
        // oplog once again would fail.
        // To ensure we are working with a clean oplog (an oplog without entries), we resort
        // to truncating the oplog instead.
        if (!oplog.getDB().getCollectionNames().includes(oplog.getName())) {
            oplog.getDB().createCollection(oplog.getName(), newCollectionSpec);
        }
        oplog.runCommand('emptycapped');
        oplog.getDB().adminCommand({replSetResizeOplog: 1, size: 16 * 1024});
    } else {
        oplog.drop();
        assert.commandWorked(oplog.getDB().createCollection(oplog.getName(), newCollectionSpec));
    }
}

dropOplogAndCreateNew(t, {capped: true, size: 16 * 1024});

/**
 * Helper function for making timestamps with the property that if i < j, then makeTS(i) <
 * makeTS(j).
 */
function makeTS(i) {
    return Timestamp(1000, i);
}

for (let i = 1; i <= 100; i++) {
    assert.commandWorked(t.insert({_id: i, ts: makeTS(i)}));
}

// A $gt query on just the 'ts' field should return the next document after the timestamp.
var cursor = t.find({ts: {$gt: makeTS(20)}});
assert.eq(21, cursor.next()["_id"]);
assert.eq(22, cursor.next()["_id"]);

// A $gte query on the 'ts' field should include the timestamp.
cursor = t.find({ts: {$gte: makeTS(20)}});
assert.eq(20, cursor.next()["_id"]);
assert.eq(21, cursor.next()["_id"]);

// An $eq query on the 'ts' field should return the single record with the timestamp.
cursor = t.find({ts: {$eq: makeTS(20)}});
assert.eq(20, cursor.next()["_id"]);
assert(!cursor.hasNext());

// An AND with both a $gt and $lt query on the 'ts' field will correctly return results in
// the proper bounds.
cursor = t.find({$and: [{ts: {$lt: makeTS(5)}}, {ts: {$gt: makeTS(1)}}]});
assert.eq(2, cursor.next()["_id"]);
assert.eq(3, cursor.next()["_id"]);
assert.eq(4, cursor.next()["_id"]);
assert(!cursor.hasNext());

// An AND with multiple predicates on the 'ts' field correctly returns results on the
// tightest range.
cursor = t.find({
    $and: [
        {ts: {$gte: makeTS(2)}},
        {ts: {$gt: makeTS(3)}},
        {ts: {$lte: makeTS(7)}},
        {ts: {$lt: makeTS(7)}}
    ]
});
assert.eq(4, cursor.next()["_id"]);
assert.eq(5, cursor.next()["_id"]);
assert.eq(6, cursor.next()["_id"]);
assert(!cursor.hasNext());

// An AND with an $eq predicate in conjunction with other bounds correctly returns one
// result.
cursor = t.find({
    $and: [
        {ts: {$gte: makeTS(1)}},
        {ts: {$gt: makeTS(2)}},
        {ts: {$eq: makeTS(5)}},
        {ts: {$lte: makeTS(8)}},
        {ts: {$lt: makeTS(8)}}
    ]
});
assert.eq(5, cursor.next()["_id"]);
assert(!cursor.hasNext());

// An $eq query stops scanning after passing the max timestamp.
let res = t.find({ts: {$eq: makeTS(10)}}).explain("executionStats");
assert.commandWorked(res);
// We expect to be able to seek directly to the entry with a 'ts' of 10.
assert.lte(res.executionStats.totalDocsExamined, 2, tojson(res));
let collScanStage = getPlanStage(res.executionStats.executionStages, "COLLSCAN");
assert.neq(null, collScanStage, "no collection scan found in explain output: " + tojson(res));
assert.eq(makeTS(10), collScanStage.maxTs, tojson(res));

// An AND with an $lt predicate stops scanning after passing the max timestamp.
res = t.find({$and: [{ts: {$gte: makeTS(1)}}, {ts: {$lt: makeTS(10)}}]}).explain("executionStats");
assert.commandWorked(res);
assert.lte(res.executionStats.totalDocsExamined, 11, tojson(res));
collScanStage = getPlanStage(res.executionStats.executionStages, "COLLSCAN");
assert.neq(null, collScanStage, "no collection scan found in explain output: " + tojson(res));
assert.eq(makeTS(10), collScanStage.maxTs, tojson(res));

// An AND with an $lte predicate stops scanning after passing the max timestamp.
res = t.find({$and: [{ts: {$gte: makeTS(1)}}, {ts: {$lte: makeTS(10)}}]}).explain("executionStats");
assert.commandWorked(res);
assert.lte(res.executionStats.totalDocsExamined, 12, tojson(res));
collScanStage = getPlanStage(res.executionStats.executionStages, "COLLSCAN");
assert.neq(null, collScanStage, "no collection scan found in explain output: " + tojson(res));
assert.eq(makeTS(10), collScanStage.maxTs, tojson(res));

// The max timestamp is respected even when the min timestamp is smaller than the lowest
// timestamp in the collection.
res = t.find({$and: [{ts: {$gte: makeTS(0)}}, {ts: {$lte: makeTS(10)}}]}).explain("executionStats");
assert.commandWorked(res);
assert.lte(res.executionStats.totalDocsExamined, 12, tojson(res));
collScanStage = getPlanStage(res.executionStats.executionStages, "COLLSCAN");
assert.neq(null, collScanStage, "no collection scan found in explain output: " + tojson(res));
assert.eq(makeTS(10), collScanStage.maxTs, tojson(res));

// An AND with redundant $eq/$lt/$lte predicates stops scanning after passing the max
// timestamp.
res = t.find({
           $and: [
               {ts: {$gte: makeTS(0)}},
               {ts: {$lte: makeTS(10)}},
               {ts: {$eq: makeTS(5)}},
               {ts: {$lt: makeTS(20)}}
           ]
       }).explain("executionStats");
assert.commandWorked(res);
// We expect to be able to seek directly to the entry with a 'ts' of 5.
assert.lte(res.executionStats.totalDocsExamined, 2, tojson(res));
collScanStage = getPlanStage(res.executionStats.executionStages, "COLLSCAN");
assert.neq(null, collScanStage, "no collection scan found in explain output: " + tojson(res));
assert.eq(makeTS(5), collScanStage.maxTs, tojson(res));
assert.eq(makeTS(5), collScanStage.minTs, tojson(res));

// An $eq query for a non-existent timestamp scans a single oplog document.
res = t.find({ts: {$eq: makeTS(200)}}).explain("executionStats");
assert.commandWorked(res);
// We expect to be able to seek directly to the end of the oplog.
assert.lte(res.executionStats.totalDocsExamined, 1, tojson(res));
collScanStage = getPlanStage(res.executionStats.executionStages, "COLLSCAN");
assert.neq(null, collScanStage, "no collection scan found in explain output: " + tojson(res));
assert.eq(makeTS(200), collScanStage.maxTs, tojson(res));

// When the filter matches the last document within the timestamp range, the collection scan
// examines at most one more document.
res = t.find({
           $and: [{ts: {$gte: makeTS(4)}}, {ts: {$lte: makeTS(8)}}, {_id: 8}]
       }).explain("executionStats");
assert.commandWorked(res);
// We expect to be able to seek directly to the start of the 'ts' range.
assert.lte(res.executionStats.totalDocsExamined, 6, tojson(res));
collScanStage = getPlanStage(res.executionStats.executionStages, "COLLSCAN");
assert.neq(null, collScanStage, "no collection scan found in explain output: " + tojson(res));
assert.eq(makeTS(8), collScanStage.maxTs, tojson(res));

// A filter with only an upper bound predicate on 'ts' stops scanning after
// passing the max timestamp.
res = t.find({ts: {$lt: makeTS(4)}}).explain("executionStats");
assert.commandWorked(res);
assert.lte(res.executionStats.totalDocsExamined, 4, tojson(res));
collScanStage = getPlanStage(res.executionStats.executionStages, "COLLSCAN");
assert.neq(null, collScanStage, "no collection scan found in explain output: " + tojson(res));
assert.eq(makeTS(4), collScanStage.maxTs, tojson(res));

// Oplog replay optimization should work with projection.
res = t.find({ts: {$lte: makeTS(4)}}).projection({'_id': 0});
while (res.hasNext()) {
    const next = res.next();
    assert(!next.hasOwnProperty('_id'));
    assert(next.hasOwnProperty('ts'));
}
res = res.explain("executionStats");
assert.commandWorked(res);
assert.lte(res.executionStats.totalDocsExamined, 5);

res = t.find({ts: {$gte: makeTS(90)}}).projection({'_id': 0});
while (res.hasNext()) {
    const next = res.next();
    assert(!next.hasOwnProperty('_id'));
    assert(next.hasOwnProperty('ts'));
}
res = res.explain("executionStats");
assert.commandWorked(res);
assert.lte(res.executionStats.totalDocsExamined, 11);

// Oplog replay optimization should work with limit.
res = t.find({$and: [{ts: {$gte: makeTS(4)}}, {ts: {$lte: makeTS(8)}}]})
          .limit(2)
          .explain("executionStats");
assert.commandWorked(res);
assert.eq(2, res.executionStats.totalDocsExamined);
collScanStage = getPlanStage(res.executionStats.executionStages, "COLLSCAN");
assert.eq(2, collScanStage.nReturned);

// A query over both 'ts' and '_id' should only pay attention to the 'ts' field for finding
// the oplog start (SERVER-13566).
cursor = t.find({ts: {$gte: makeTS(20)}, _id: 25});
assert.eq(25, cursor.next()["_id"]);
assert(!cursor.hasNext());

// 'oplogreplay' flag is allowed but ignored on the oplog collection.
assert.commandWorked(t.runCommand({find: t.getName(), oplogReplay: true}));

// 'oplogreplay' flag is allowed but ignored on capped collections.
const cappedColl = db.cappedColl_jstests_query_oplogreplay;
cappedColl.drop();
assert.commandWorked(db.createCollection(cappedColl.getName(), {capped: true, size: 16 * 1024}));
for (let i = 1; i <= 100; i++) {
    assert.commandWorked(cappedColl.insert({_id: i, ts: makeTS(i)}));
}
res = cappedColl.runCommand(
    {explain: {find: cappedColl.getName(), filter: {ts: {$eq: makeTS(200)}}, oplogReplay: true}});
assert.commandWorked(res);
assert.eq(res.executionStats.totalDocsExamined, 100);

// Ensure oplog replay hack does not work for backward scans.
res = t.find({ts: {$lt: makeTS(4)}}).sort({$natural: -1}).explain("executionStats");
assert.commandWorked(res);
assert.eq(res.executionStats.totalDocsExamined, 100, tojson(res));
collScanStage = getPlanStage(res.executionStats.executionStages, "COLLSCAN");
assert.neq(null, collScanStage, "no collection scan found in explain output: " + tojson(res));

// We expect correct results when no collation specified and collection has a default collation.
const testCollation = db.getSiblingDB("local").oplog.jstests_query_oplogreplay_collation;
dropOplogAndCreateNew(testCollation,
                      {collation: {locale: "en_US", strength: 2}, capped: true, size: 16 * 1024});

assert.commandWorked(testCollation.insert({str: "FOO", ts: Timestamp(1000, 0)}));
assert.commandWorked(testCollation.insert({str: "FOO", ts: Timestamp(1000, 1)}));
assert.commandWorked(testCollation.insert({str: "FOO", ts: Timestamp(1000, 2)}));
assert.eq(2, testCollation.find({str: "foo", ts: {$gte: Timestamp(1000, 1)}}).itcount());

// We expect correct results when "simple" collation specified and collection has a default
// collation.
dropOplogAndCreateNew(testCollation,
                      {collation: {locale: "en_US", strength: 2}, capped: true, size: 16 * 1024});
assert.commandWorked(testCollation.insert({str: "FOO", ts: Timestamp(1000, 0)}));
assert.commandWorked(testCollation.insert({str: "FOO", ts: Timestamp(1000, 1)}));
assert.commandWorked(testCollation.insert({str: "FOO", ts: Timestamp(1000, 2)}));
assert.eq(0,
          testCollation.find({str: "foo", ts: {$gte: Timestamp(1000, 1)}})
              .collation({locale: "simple"})
              .itcount());
}());