my mongodb is a MMAPv1 engine, how to view and set lock granularity?
my mongodb is a MMAPv1 engine, how to view and set lock granularity?
as far as I know, no database can "set" lock granularity. What is the purpose of setting the granularity of the lock? The
MMAPv1 engine is at the collection level after > = 3.0, and before it is at the database level.
you can take a look at the document FAQ Concurrency
Previous: React configuration
Room schema var Room = new Schema({ title: String, author: String, body: String, owners: [ { type: ObjectId, ref: User , index: true } ] }) Room.find({ owners: user }) first question: why can the query here be written this way? How...
after mongodb has designed the schema, it has been running normally for some time (data is already available). When you adjust the schema later, for example, to add a field and decrease a field, what to do with the original data? do you have to wash the ...
const Article = new Schema({ Title: { type: String, required: true }, Content: { type: String, required: true }, CreatedAt: { type: Date, default: new Date, get: v => moment(v).format( YYYY-MM-DD HH:mm )}, UpdatedAt: { type: Date, d...
when you associate with mysql, you can use id to associate, and you can store two tables during the same database operation. Because the primary key id can be self-increasing and is not affected by other factors, the two tables can be associated with id,...
is to create a data table of contacts, and then the front end searches the corresponding friends through its own username and traverses to the page this is my mongoose schema var contactSchema = new Schema({ user1:{ type:Object, required:true...
Two tables in mongodb, one is users and the other is called userDetails. What needs to be done now is that according to the user details corresponding to the userId query, the query is operated in userDetails. has been tested that the data in the table...