valkey-io/valkey

[BUG] Stream lag value could be incorrect

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#641 opened on Jun 12, 2024

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help wanted

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Description

Describe the bug

This blog post describes a bug in Streams that also affects Valkey

To reproduce

See linked blog post above.

Expected behavior

See linked blog post above.

Additional information

I've recreated the issue from the blog post in Valkey 7.2.5 and the (wrong) behaviour with lag is still being exhibited.

Contributor guide

Research direction
Examine the stream lag calculation in source code, specifically the function `streamReplyWithRangeFromStream` and related replication logic. Trace the execution path for the bug case described in the blog post.
Tech stack
credis
Domain
backenddatabase
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
GitC
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50