Transactions in Redis

Redis as a NOSQL data store provides a loose sense of transaction. As in a traditional RDBMS, the transaction starts with a BEGIN and ends with either COMMIT or ROLLBACK. All these RDBMS servers are multithreaded, so when a thread locks a resource, it cannot be manipulated by another thread unless and until the lock is released. Redis by default has MULTI to start and EXEC to execute the commands. In case of a transaction, the first command is always MULTI, and after that all the commands are stored, and when EXEC command is received, all the stored commands are executed in sequence. So inside the hood, once Redis receives the EXEC command, all the commands are executed as a single isolated operation. Following are the commands that can be used in Redis for transaction:

• MULTI: This marks the start of a transaction block
• EXEC: This executes all the commands in the pipeline after MULTI
• WATCH: This watches the keys for conditional execution of a transaction
• UNWATCH: This...