Fix error when inserting into time series collections

[pavlos163]

Versions

• NodeJS: 20.11.1
• mongodb-memory-server-*: 10.1.2
• mongodb(the binary version): 8.0.3
• mongoose: 8.8.2
• system: Linux Debian (from node:20.11.1-slim Docker image)

package: mongo-memory-server

What is the Problem?

When using mongodb-memory-server with a timeseries collection in test environment, attempting to insert documents results in MongoServerError: Namespace X is a view, not a collection. The same code works correctly with a local MongoDB instance.

This appears to be a discrepancy in how mongodb-memory-server handles timeseries collections compared to a standard MongoDB installation.

Code Example

// Model definition
const postSchema: Schema = new mongoose.Schema(
  {
    date: {
      type: Date,
      required: true
    },
    content: {
      type: String,
      required: true
    }
  },
  {
    toJSON: { virtuals: true },
    toObject: { virtuals: true },
    timeseries: {
      timeField: "date",
      granularity: "hours"
    },
    autoCreate: true,
    timestamps: true
  }
);

export const Post = mongoose.model<PostDocument>("Post", postSchema);

// Test setup
const { MongoMemoryReplSet } = require("mongodb-memory-server");

const MONGO_VERSION = "8.0.3";

module.exports = async () => {
  const replicaSet = await MongoMemoryReplSet.create({
    instanceOpts: [
      {
        port: parseInt(process.env.DATABASE_IN_MEMORY_PORT)
      }
    ],
    binary: {
      version: MONGO_VERSION
    },
    replSet: { count: 1, storageEngine: "wiredTiger" }
  });
};

// Test that fails
describe("createAllPosts", () => {
  beforeAll(async () => {
    await buildPost({
      content: "test content",
    });
  });

  it("should work with timeseries collection", async () => {
    const posts = await Post.find();
    expect(posts.length).toBe(1);
  });
});

// helpers
async function buildPost(
  overrides: Partial<PostDTOInterface> = {}
): Promise<PostDocument> {
  const data: PostDTOInterface = {
    date: new Date(Date.now()),
    content: faker.lorem.sentence(),
    ...overrides
  };

  return new Post(data).save();
}

Error output

MongoServerError: Namespace PostCronService.posts is a view, not a collection
    at InsertOneOperation.execute (node_modules/mongodb/src/operations/insert.ts:82:13)
    at tryOperation (node_modules/mongodb/src/operations/execute_operation.ts:271:14)
    at executeOperation (node_modules/mongodb/src/operations/execute_operation.ts:109:12)
    at Collection.insertOne (node_modules/mongodb/src/collection.ts:277:12)

Do you know why it happens?

The issue seems specific to mongodb-memory-server as:

• The exact same code works correctly with a local MongoDB instance
• MongoDB 8.0.3 fully supports timeseries collections

[hasezoey]

When using mongodb-memory-server with a timeseries collection in test environment, attempting to insert documents results in MongoServerError: Namespace X is a view, not a collection

That sounds like a weird error.

This appears to be a discrepancy in how mongodb-memory-server handles timeseries collections compared to a standard MongoDB installation.

mongodb-memory-server is basically a local installation, as MMS literally only handles download & running mongod binaries, so there shouldnt be a discrepancy with the same options.

---

In what part of the provided code does the error occur?
What version were you using when testing a "local installation"? (was that also a repl-set?)