mongodb/jstests/sharding/migration_sets_fromMigrate_flag.js

//
// Tests whether the fromMigrate flag is correctly set during migrations.
//
// Tests:
//      #1 (delete op) fromMigrate is set when recipient shard deletes all documents locally
//         in the chunk range it is about to receive from the donor shard.
//      #2 (delete op) fromMigrate is set when the donor shard deletes documents that have
//         been migrated to another shard.
//      #3 (insert op) fromMigrate is set when the recipient shard receives chunk migration
//         data and inserts it.
//      #4 (update op) fromMigrate is set when an update occurs in the donor shard during
//         migration and is sent to the recipient via the transfer logs.
//      #5 fromMigrate is NOT set on donor shard and IS set on the recipient shard when real
//         delete op is done during chunk migration within the chunk range.
//

import {
    migrateStepNames,
    moveChunkParallel,
    pauseMigrateAtStep,
    unpauseMigrateAtStep,
    waitForMigrateStep,
} from "jstests/libs/chunk_manipulation_util.js";
import {FeatureFlagUtil} from "jstests/libs/feature_flag_util.js";
import {ShardingTest} from "jstests/libs/shardingtest.js";

var staticMongod = MongoRunner.runMongod({});

var st = new ShardingTest({shards: 2, mongos: 1, rs: {nodes: 1}});

const dbName = "testDB";
const ns = dbName + ".foo";

let mongos = st.s0;
let admin = mongos.getDB('admin');
let coll = mongos.getCollection(ns);

let donor = st.shard0;
let recipient = st.shard1;
let donorColl = donor.getCollection(ns);
let recipientColl = recipient.getCollection(ns);
let donorLocal = donor.getDB('local');
let recipientLocal = recipient.getDB('local');

// Two chunks
// Donor:     [0, 2) [2, 5)
// Recipient:
jsTest.log('Enable sharding of the collection and split into two chunks....');

assert.commandWorked(admin.runCommand({enableSharding: dbName, primaryShard: st.shard0.shardName}));
assert.commandWorked(admin.runCommand({shardCollection: ns, key: {_id: 1}}));
assert.commandWorked(admin.runCommand({split: ns, middle: {_id: 2}}));

// 6 documents,
//        donor: 2 in the first chunk, 3 in the second.
//    recipient: 1 document (shardkey overlaps with a doc in second chunk of donor shard)
jsTest.log('Inserting 5 docs into donor shard, ensuring one orphan on the recipient shard....');

// Insert just one document into the collection and fail a migration after the cloning step in
// order to get an orphan onto the recipient shard with the correct UUID for the collection.
assert.commandWorked(coll.insert({_id: 2}));
assert.eq(1, donorColl.count());
assert.commandWorked(
    recipient.adminCommand({configureFailPoint: "failMigrationOnRecipient", mode: "alwaysOn"}));
assert.commandFailed(
    admin.runCommand({moveChunk: coll.getFullName(), find: {_id: 2}, to: st.shard1.shardName}));
assert.commandWorked(
    recipient.adminCommand({configureFailPoint: "failMigrationOnRecipient", mode: "off"}));

// Insert the remaining documents into the collection.
assert.commandWorked(coll.insert({_id: 0}));
assert.commandWorked(coll.insert({_id: 1}));
assert.commandWorked(coll.insert({_id: 3}));
assert.commandWorked(coll.insert({_id: 4}));
assert.eq(5, donorColl.count());

/**
 * Set failpoint: recipient will pause migration after cloning chunk data from donor,
 * before checking transfer mods log on donor.
 */

jsTest.log('setting recipient failpoint cloned');
pauseMigrateAtStep(recipient, migrateStepNames.cloned);

/**
 * Start moving chunk [2, 5) from donor shard to recipient shard, run in the background.
 */

// Donor:     [0, 2)
// Recipient:    [2, 5)
jsTest.log('Starting chunk migration, pause after cloning...');

var joinMoveChunk = moveChunkParallel(
    staticMongod, st.s0.host, {_id: 2}, null, coll.getFullName(), st.shard1.shardName);

/**
 * Wait for recipient to finish cloning.
 * THEN update 1 document {_id: 3} on donor within the currently migrating chunk.
 * AND delete 1 document {_id: 4} on donor within the currently migrating chunk.
 */

waitForMigrateStep(recipient, migrateStepNames.cloned);

jsTest.log('Update 1 doc and delete 1 doc on donor within the currently migrating chunk...');

assert.commandWorked(coll.update({_id: 3}, {_id: 3, a: "updated doc"}));
assert.commandWorked(coll.remove({_id: 4}));

/**
 * Finish migration. Unpause recipient migration, wait for it to collect
 * the transfer mods log from donor and finish migration.
 */

jsTest.log('Continuing and finishing migration...');
unpauseMigrateAtStep(recipient, migrateStepNames.cloned);
joinMoveChunk();

/**
 * Check documents are where they should be: 2 docs in donor chunk, 2 docs in recipient chunk
 * (because third doc in recipient shard's chunk got deleted on the donor shard during
 * migration).
 */

jsTest.log('Checking that documents are on the shards they should be...');

assert.eq(2, recipientColl.count(), "Recipient shard doesn't have exactly 2 documents!");
assert.eq(2, donorColl.count(), "Donor shard doesn't have exactly 2 documents!");
assert.eq(4, coll.count(), "Collection total is not 4!");

/**
 * Check that the fromMigrate flag has been set correctly in donor and recipient oplogs,
 */

jsTest.log('Checking donor and recipient oplogs for correct fromMigrate flags...');

function assertEqAndDumpOpLog(expected, actual, msg) {
    if (expected === actual)
        return;

    const oplogFilter = {$or: [{ns: ns}, {"o.applyOps.0.ns": ns}]};
    print('Dumping oplog contents for', ns);
    print('On donor:');
    print(tojson(donorLocal.oplog.rs.find(oplogFilter).toArray()));

    print('On recipient:');
    print(tojson(recipientLocal.oplog.rs.find(oplogFilter).toArray()));

    assert.eq(expected, actual, msg);
}

var donorOplogRes = donorLocal.oplog.rs.find({op: 'd', fromMigrate: true, 'o._id': 2}).count();
assertEqAndDumpOpLog(1,
                     donorOplogRes,
                     "fromMigrate flag wasn't set on the donor shard's oplog for " +
                         "migrating delete op on {_id: 2}! Test #2 failed.");

donorOplogRes =
    donorLocal.oplog.rs.find({op: 'd', fromMigrate: {$exists: false}, 'o._id': 4}).count();
if (!donorOplogRes) {
    // Validate this is a batched delete, which generates one applyOps entry instead of a 'd' entry.
    donorOplogRes =
        donorLocal.oplog.rs
            .find({
                ns: 'admin.$cmd',
                op: 'c',
                'o.applyOps': {$elemMatch: {op: 'd', 'o._id': 4, fromMigrate: {$exists: false}}}
            })
            .count();
}
assertEqAndDumpOpLog(1,
                     donorOplogRes,
                     "Real delete of {_id: 4} on donor shard incorrectly set the " +
                         "fromMigrate flag in the oplog! Test #5 failed.");

let recipientOplogRes =
    recipientLocal.oplog.rs.find({op: 'i', fromMigrate: true, 'o._id': 2}).count();
if (FeatureFlagUtil.isPresentAndEnabled(recipientLocal,
                                        "ReplicateVectoredInsertsTransactionally")) {
    // Expect to see one insert oplog entry for _id:2 because that doc was cloned on its own as part
    // of the failed migrate.  Also expect to see one applyOps entry containing _id:2 as part of a
    // batched insert from the second migrate
    assertEqAndDumpOpLog(1,
                         recipientOplogRes,
                         "fromMigrate flag wasn't set on the recipient shard's " +
                             "oplog for migrating insert op on {_id: 2}! Test #3 failed.");

    // Note we expect the applyOps to have fromMigrate set, and also the operation within the
    // applyOps to have fromMigrate set.
    recipientOplogRes = recipientLocal.oplog.rs
                            .find({
                                op: 'c',
                                fromMigrate: true,
                                'o.applyOps': {$elemMatch: {fromMigrate: true, 'o._id': 2}}
                            })
                            .count();
    assertEqAndDumpOpLog(1,
                         recipientOplogRes,
                         "fromMigrate flag wasn't set on the recipient shard's " +
                             "applyOps entry for migrating insert op on {_id: 2}! Test #3 failed.");

} else {
    // Expect to see two oplog entries for {_id: 2} with 'fromMigrate: true' because this doc was
    // cloned as part of the first failed migration as well as the second successful migration.
    assertEqAndDumpOpLog(2,
                         recipientOplogRes,
                         "fromMigrate flag wasn't set on the recipient shard's " +
                             "oplog for migrating insert op on {_id: 2}! Test #3 failed.");
}

recipientOplogRes = recipientLocal.oplog.rs.find({op: 'd', fromMigrate: true, 'o._id': 2}).count();
assertEqAndDumpOpLog(1,
                     recipientOplogRes,
                     "fromMigrate flag wasn't set on the recipient shard's " +
                         "oplog for delete op on the old {_id: 2} that overlapped " +
                         "with the chunk about to be copied! Test #1 failed.");

recipientOplogRes = recipientLocal.oplog.rs.find({op: 'u', fromMigrate: true, 'o._id': 3}).count();
assertEqAndDumpOpLog(1,
                     recipientOplogRes,
                     "fromMigrate flag wasn't set on the recipient shard's " +
                         "oplog for update op on {_id: 3}! Test #4 failed.");

recipientOplogRes = recipientLocal.oplog.rs.find({op: 'd', fromMigrate: true, 'o._id': 4}).count();
assertEqAndDumpOpLog(1,
                     recipientOplogRes,
                     "fromMigrate flag wasn't set on the recipient shard's " +
                         "oplog for delete op on {_id: 4} that occurred during " +
                         "migration! Test #5 failed.");

st.stop();
MongoRunner.stopMongod(staticMongod);