Nosql Redis: transaction processing and operation commands

Multi indicates the start of a transaction, and multiple commands in the transaction block are sequentially put into a queue, and finally executed by exec. time Complexity: O (1) Return Value: total returns OKdiscard to cancel the transaction and discard all commands of the transaction block. if you are using watch monitoring, all monitoring will be canceled. time Complexity: O (1) Return Value: Total Return OKwatch format: wathck

Multi indicates the start of a transaction, and multiple commands in the transaction block are sequentially put into a queue, and finally executed by exec. time Complexity: O (1) Return Value: always return OK discard to cancel the transaction and discard all commands of the transaction block. if you are using watch monitoring, all monitoring will be canceled. time Complexity: O (1) Return Value: Total Return OK watch format: wathc k

Multi
Mark the start of a transaction. Multiple commands in the transaction block are sequentially put into a queue and finally executed by exec.
Time Complexity: O (1)
Return Value: Always Returns OK
Discard
Cancel the transaction and discard all commands of the transaction block. If you are using watch monitoring, all monitoring will be canceled.
Time Complexity: O (1)
Return Value: Always Returns OK

Watch
Format: wathc key [key...]
Specifies the KEY (multiple keys) to be monitored. If this (or these) key is changed by other commands before the transaction is executed, the transaction will be interrupted.
Time Complexity: O (1)
Return Value: Always Returns OK

Exec
Execute all the commands in the transaction block. (note the watch mentioned above ).
Time Complexity:
The sum of time complexity of all commands in the transaction block.
Return Value:
The return values of all commands in the transaction block are arranged in order of command execution.
When the operation is interrupted, the return value is nil.

========================================================== = Normal transactions: # Start a new transaction redis 127.0.0.1: 6379> multiOK # execute a command. It can be seen from the returned results that the command is not executed immediately, but added to the transaction queue. redis 127.0.0.1: 6379> set key_id 2 QUEUED # two identical redis 127.0.0.1: 6379> incr key_idQUEUEDredis 127.0.0.1: 6379> incr key_idQUEUED # submit transaction redis 127.0.0.1: 6379> exec1) OK2) (integer) 33) (integer) 4 ============================================== # monitoring key, successful transaction execution: redis 127.0.0.1: 6379> watch key_idOKredis 127.0.0.1: 6379> multiOKredis 127.0.0.1: 6379> incr 2017127.0.0.1: 6379> incr key_idQUEUEDredis 127.0.0.1: 6379> exec1) (integer) 52) (integer) 6 ================================================ = # monitoring key, and the transaction is interrupted redis 127.0.0.1: 6379> watch key_idOKredis 127.0.0.1: 6379> multiOK # set key_id 10 redis 127.0.0.1 has been executed by another user before this: 6379> set key_id 12 QUEUED # The transaction fails to be executed because the key_id is modified. redis 127.0.0.1: 6379> exec (nil) redis 127.0.0.1: 6379> get key_id "10" ==================================== ========## redis 127.0.0.1 error in the transaction: 6379> multiOKredis 127.0.0.1: 6379> set key_id 14 QUEUEDredis 127.0.0.1: 6379> set nma (error) ERR wrong number of arguments for 'set' command # When an error occurs in redis, no rollback. other commands are still executed as usual. this is also the redis 127.0.0.1: 6379> exec1) OK