Why persistence matters in Redis - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to save the current Redis database state to disk immediately.

Redis

redis-cli [1]

Drag options to blanks, or click blank then click option'

ASAVE

BFLUSHDB

CGET

DDEL

Attempts:

3 left

💡 Hint

Common Mistakes

Using FLUSHDB deletes data instead of saving it.

Using GET or DEL does not save data.

The SAVE command forces Redis to save the dataset to disk immediately, ensuring data persistence.

2fill in blank

medium

Complete the code to enable Redis to save snapshots every 60 seconds if at least 1000 keys changed.

Redis

save [1] 1000

Drag options to blanks, or click blank then click option'

A30

B120

C300

D60

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a time interval too short or too long for the requirement.

The configuration save 60 1000 tells Redis to save a snapshot every 60 seconds if 1000 keys changed, helping persistence.

3fill in blank

hard

Fix the error in the command to rewrite the AOF file for persistence.

Redis

redis-cli [1]

Drag options to blanks, or click blank then click option'

ABGREWRITEAOF

BAPPENDAOF

CAOFAPPEND

DBGSAVE

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent commands like APPENDAOF or AOFAPPEND.

Confusing with BGSAVE which saves RDB snapshots.

The correct command to rewrite the Append Only File (AOF) in the background is BGREWRITEAOF. It helps maintain persistence efficiently.

4fill in blank

hard

Fill both blanks to configure Redis to use AOF persistence and disable RDB preamble in AOF files.

Redis

appendonly [1]
aof-use-rdb-preamble [2]

Drag options to blanks, or click blank then click option'

Ayes

Bno

Ceverysec

Dalways

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing fsync policy with aof-use-rdb-preamble setting.

Using 'everysec' or 'always' for boolean options.

Setting appendonly yes enables AOF persistence. Setting aof-use-rdb-preamble no disables RDB preamble in AOF files.

5fill in blank

hard

Fill all three blanks to create a Redis configuration snippet that enables AOF, sets fsync policy to every second, and disables RDB snapshots.

Redis

appendonly [1]
appendfsync [2]
save [3]

Drag options to blanks, or click blank then click option'

Ayes

Beverysec

C""

Dno

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'no' to enable AOF.

Setting fsync to 'always' instead of 'everysec'.

Not disabling RDB snapshots properly.

Enable AOF with appendonly yes, set fsync to every second with appendfsync everysec, and disable RDB snapshots by setting save "".