DISCARD to abort in Redis - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the DISCARD command do in Redis transactions?

It cancels all commands queued in the current transaction and exits the transaction without executing any of them.

beginner

When should you use DISCARD in Redis?

Use DISCARD when you want to abort a transaction because something went wrong or you no longer want to execute the queued commands.

intermediate

What happens if you run DISCARD without starting a transaction with MULTI?

Redis will return an error because DISCARD only works inside a transaction block started by MULTI.

intermediate

How does DISCARD affect the Redis command queue?

It clears the queue of commands that were added after MULTI and before EXEC, so none of those commands run.

beginner

Compare DISCARD and EXEC in Redis transactions.

EXEC runs all queued commands in the transaction, while DISCARD cancels them all without running anything.

What does the Redis DISCARD command do?

A Starts a new transaction

B Executes all queued commands in a transaction

C Cancels all queued commands in a transaction

D Commits changes to the database

DISCARD cancels all commands queued after MULTI and aborts the transaction.

When can you use DISCARD in Redis?

A Only after <code>EXEC</code>

B Only after <code>MULTI</code> and before <code>EXEC</code>

C At any time

D Only before <code>MULTI</code>

DISCARD works only inside a transaction block, after MULTI and before EXEC.

What happens if you run DISCARD without starting a transaction?

A It clears the database

B It does nothing

C It starts a transaction

D It returns an error

DISCARD requires a transaction started by MULTI. Without it, Redis returns an error.

Which command in Redis actually runs the queued commands in a transaction?

A EXEC

B MULTI

C DISCARD

D WATCH

EXEC executes all commands queued after MULTI.

If you want to cancel a transaction in Redis, which command should you use?

A DISCARD

B EXEC

C MULTI

D SAVE

DISCARD aborts the transaction and clears the queued commands.

Explain how the DISCARD command works in Redis transactions and when you would use it.

Think about stopping a group of commands before they run.

Describe the difference between EXEC and DISCARD in Redis transactions.

One means go, the other means stop.