Atomicity not guaranteed when using BulkWrite

[fourjae]

Description:

Atomicity must be guaranteed when performing bulk updates using 'bulkwrite' in mongodb.

Why:

yorkie/server/backend/database/mongo/client.go

Line 888 in 1b557be

if _, err = c.collection(colChanges).BulkWrite(

There is no guarantee of atomicity when using bulkWrite.

Transactions are required when processing many operations. However, this causes performance problems.
Which method should I use?

references:

• To make the BulkWrite operation atomic, use Transactions.

[hackerwins]

@fourjae

Yorkie Server follows a specific approach when editing a Document.

It first stores all the changes that occur during document editing in the changes collection. Then it stores the last change to server_seq in the "documents" collection. This storage process does not execute queries into transactions, to reduce the load on the database.

Even if the storage process encounters failures, the server_seq stored in the documents collection remains unaffected. When other requests attempt to load changes or save further changes, they operate based on server_seq in the documents collection. If necessary, these requests may overwrite the changes.