mongo/jstests/sharding/unshard_collection_basic.js

/**
 * Tests for basic functionality of the unshard collection feature.
 *
 * @tags: [
 *  requires_fcv_80,
 *  featureFlagUnshardCollection,
 *  assumes_balancer_off,
 * ]
 */

import {FeatureFlagUtil} from "jstests/libs/feature_flag_util.js";
import {ShardingTest} from "jstests/libs/shardingtest.js";

(function () {
    "use strict";

    let st = new ShardingTest({mongos: 1, shards: 2});

    const dbName = "db";
    const collName = "foo";
    const ns = dbName + "." + collName;
    let mongos = st.s0;
    let shard0 = st.shard0.shardName;
    let shard1 = st.shard1.shardName;
    let cmdObj = {unshardCollection: ns, toShard: shard1};

    // Fail if unsharded collection.
    assert.commandFailedWithCode(mongos.adminCommand(cmdObj), ErrorCodes.NamespaceNotFound);

    assert.commandWorked(mongos.adminCommand({enableSharding: dbName, primaryShard: shard0}));

    let coll = mongos.getDB(dbName)[collName];
    assert.commandWorked(coll.insert({oldKey: 50}));

    const unshardedCollName = "foo_unsharded";
    const unshardedCollNS = dbName + "." + unshardedCollName;
    assert.commandWorked(st.s.getDB(dbName).runCommand({create: unshardedCollName}));
    let res = mongos.adminCommand({unshardCollection: unshardedCollNS});
    assert.commandFailedWithCode(res, [ErrorCodes.NamespaceNotFound, ErrorCodes.NamespaceNotSharded]);

    assert.commandWorked(coll.createIndex({oldKey: 1}));
    assert.commandWorked(mongos.adminCommand({shardCollection: ns, key: {oldKey: 1}}));

    assert.commandWorked(mongos.adminCommand({split: ns, middle: {oldKey: 0}}));
    assert.commandWorked(mongos.adminCommand({moveChunk: ns, find: {oldKey: -1}, to: shard0}));
    assert.commandWorked(mongos.adminCommand({moveChunk: ns, find: {oldKey: 10}, to: shard1}));

    coll = mongos.getDB(dbName)[collName];
    for (let i = -25; i < 25; ++i) {
        assert.commandWorked(coll.insert({oldKey: i}));
    }

    assert.eq(26, st.rs1.getPrimary().getCollection(ns).countDocuments({}));

    // Unshard collection should succeed with toShard option.
    assert.commandWorked(mongos.adminCommand({unshardCollection: ns, toShard: shard1}));

    // Should have unsplittable set to true
    let configDb = mongos.getDB("config");
    let unshardedColl = configDb.collections.findOne({_id: ns});
    assert.eq(unshardedColl.unsplittable, true);

    assert.eq(51, st.rs1.getPrimary().getCollection(ns).countDocuments({}));
    assert.eq(0, st.rs0.getPrimary().getCollection(ns).countDocuments({}));

    let unshardedChunk = configDb.chunks.find({uuid: unshardedColl.uuid}).toArray();
    assert.eq(1, unshardedChunk.length);

    const collInfo = mongos.getDB(dbName).getCollectionInfos({name: coll.getName()})[0];
    const prevCollUUID = collInfo.info.uuid;

    // Unshard collection should no-op with the same toShard option.
    assert.commandWorked(mongos.adminCommand({unshardCollection: ns, toShard: shard1}));
    assert.eq(mongos.getDB(dbName).getCollectionInfos({name: coll.getName()})[0].info.uuid, prevCollUUID);

    // Unshard collection should fail with the different toShard option.
    assert.commandFailedWithCode(
        mongos.adminCommand({unshardCollection: ns, toShard: shard0}),
        ErrorCodes.NamespaceNotSharded,
    );

    const newCollName = "foo1";
    const newCollNs = dbName + "." + newCollName;
    assert.commandWorked(mongos.adminCommand({shardCollection: newCollNs, key: {oldKey: 1}}));

    assert.commandWorked(mongos.adminCommand({split: newCollNs, middle: {oldKey: 0}}));
    assert.commandWorked(mongos.adminCommand({moveChunk: newCollNs, find: {oldKey: -1}, to: shard0}));
    assert.commandWorked(mongos.adminCommand({moveChunk: newCollNs, find: {oldKey: 10}, to: shard1}));

    coll = mongos.getDB(dbName)[newCollName];
    for (let i = -30; i < 30; ++i) {
        assert.commandWorked(coll.insert({oldKey: i}));
    }

    // Unshard collection should succeed without toShard option.
    assert.commandWorked(mongos.adminCommand({unshardCollection: newCollNs}));

    assert(
        st.rs1.getPrimary().getCollection(newCollNs).countDocuments({}) == 60 ||
            st.rs0.getPrimary().getCollection(newCollNs).countDocuments({}) == 60,
    );

    // Fail if command called on shard.
    assert.commandFailedWithCode(st.shard0.adminCommand(cmdObj), ErrorCodes.CommandNotFound);

    assert.commandWorked(mongos.adminCommand({shardCollection: newCollNs, key: {_id: 1}}));
    assert.commandWorked(mongos.adminCommand({split: newCollNs, middle: {_id: 0}}));
    assert.commandWorked(mongos.adminCommand({moveChunk: newCollNs, find: {_id: -1}, to: shard0}));
    assert.commandWorked(mongos.adminCommand({moveChunk: newCollNs, find: {_id: 10}, to: shard1}));

    coll = mongos.getDB(dbName)[newCollName];
    for (let i = -30; i < 30; ++i) {
        assert.commandWorked(coll.insert({_id: i}));
    }

    assert(st.rs0.getPrimary().getCollection(newCollNs).countDocuments({}) == 30);

    // Unshard collection should succeed when collection's original shard key is _id.
    assert.commandWorked(mongos.adminCommand({unshardCollection: newCollNs}));

    assert(
        st.rs1.getPrimary().getCollection(newCollNs).countDocuments({}) == 120 ||
            st.rs0.getPrimary().getCollection(newCollNs).countDocuments({}) == 120,
    );

    const metrics = st.config0.getDB("admin").serverStatus({}).shardingStatistics.unshardCollection;

    assert.eq(metrics.countStarted, 3);
    assert.eq(metrics.countSucceeded, 3);
    assert.eq(metrics.countFailed, 0);
    assert.eq(metrics.countCanceled, 0);

    st.stop();
})();