XLEN

Lesson in the Redis Roadmap · Stage 11: HyperLogLog

Last updated 14 September 2026

What is XLEN?

The XLEN command used to get the length of a stream, returning the number of entries it contains. This simple yet powerful command provides a quick way to assess the size of a stream without retrieving its contents. Unlike other Redis types, zero-length streams are possible so XLEN should be used in tandem with TYPE or EXISTS.

Study this in the interactive course See the whole Redis roadmap

Free resources to learn XLEN

Official docsXLEN

XLEN: common questions

Can I learn XLEN in Hindi?

This lesson is written in English. Once you sign in, open it in the interactive course and ask the AI tutor to explain XLEN in Hindi or Hinglish. The tutor answers from this lesson’s own text, so it stays on the syllabus, and it runs on your own Google, OpenAI or Anthropic key.

Is this XLEN tutorial for beginners?

It is lesson 94 of 162 in the free Redis roadmap, in stage 11, HyperLogLog. If you are new to Redis, start from stage 1 and come back here in order; if you already know the earlier stages, this lesson stands on its own.