Stream entry IDs in Redis - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a new entry to the stream with an auto-generated ID.

Redis

XADD mystream [1] name "Alice" age 30

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

A0-0

B1-0

CMAXLEN

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using a fixed ID like 0-0 or 1-0 instead of letting Redis generate it.

Using MAXLEN which is for trimming, not IDs.

Using * tells Redis to auto-generate the stream entry ID.

2fill in blank

medium

Complete the code to read entries from the stream starting from the given ID.

Redis

XRANGE mystream [1] +

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

A+

B0-0

C-

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using * which is for auto-generated IDs, not for reading.

Using + which means the end of the stream.

The ID 0-0 means start reading from the very first entry in the stream.

3fill in blank

hard

Fix the error in the code to add an entry with a specific ID.

Redis

XADD mystream [1] name "Bob" age 25

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

A1-0

B*

C0-0

DMAXLEN

Attempts:

3 left

💡 Hint

Common Mistakes

Using * which auto-generates the ID instead of specifying one.

Using MAXLEN which is unrelated to IDs.

To add an entry with a specific ID, use the exact ID like 1-0. Using * auto-generates the ID.

4fill in blank

hard

Fill both blanks to trim the stream to a maximum length and add a new entry with auto ID.

Redis

XADD mystream [1] [2] 10 * name "Carol" age 28

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

AMAXLEN

B*

C~

DMINID

Attempts:

3 left

💡 Hint

Common Mistakes

Using MINID instead of MAXLEN for trimming.

Omitting the approximate trimming symbol (~).

MAXLEN trims the stream to a max length, and ~ makes the trimming approximate for better performance.

5fill in blank

hard

Fill both blanks to read entries from the stream starting after a given ID and limiting the count.

Redis

XREAD COUNT [1] STREAMS mystream [2]

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

A5

B0-0

C>

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0-0 which reads from the start, not new entries.

Using COUNT 5 instead of 10 as per instruction.

COUNT 10 limits the number of entries returned, and > reads only new entries added after the last ID.