MongoDB concurrency and locking mechanism

MongoDB Concurrency and Locking Mechanism


1. In order to ensure data consistency and prevent atomicity at high concurrency, findAndModify can be used to achieve

Update update = new Update().inc("age", 1);
mongoTemplate.findAndModify(query, update, Person.class); // return's old person object
template.findAndModify(query, update, new FindAndModifyOptions().returnNew(true), Person.class);// Now return the newly updated document when updating
mongoTemplate.findAndModify(query2, update, new FindAndModifyOptions().returnNew(true).upsert(true), Person.class);//Insert if not

Reference: http://runfriends.iteye.com/blog/1830749
Reference: http://www.tuicool.com/articles/QZVNbe


MongoDB uses the lock
1. MongoDB uses the "readers-writer" lock, which is read and write Lock.
2. Lock granularity. Before version 2.2, mongod only had global locks; starting from version 2.2, most read and write operations only locked one library. Compared with previous versions, this granularity has been reduced.

Reference: http://www.bubuko.com/infodetail-998672.html