[QA] Genesis Plaza | Scene memory consumption grows continuously over time

[balducciv]

Scene memory consumption in Genesis Plaza grows continuously over time, eventually causing crashes/random bugs

🛠️ Build version:

• v0.157.0-alpha-main — macOS 26.5.2 (Tahoe), MacBook Pro M3 Pro, 18 GB (QA)
• v0.158.0-alpha-main — macOS 14.3.0, MacBook Pro M3 Pro, 18 GB (reporter)

📔 Issue Description:

Pejo reported that standing in Genesis Plaza causes System Used Memory to continuously climb with no plateau, even with only ~5 users present and minimal movement. When the memory budget threshold is reached, the scene crashes or exhibits random bugs. The same scene deployed on a separate environment (dclexperience) reportedly shows stable memory instead, pointing at something specific to the Genesis City deployment/realm rather than the scene content itself.

QA follow-up on the same build/hardware did not observe the same drastic growth within a single ~20 minute session (see Reproduction section below) — flagging this so it's investigated as a longer-duration / session-dependent issue rather than assumed to reproduce immediately.

👣 STR:

1. Launch Decentraland and teleport into Genesis Plaza
2. Open the debug panel (/debug) → expand the Memory section
3. Stand mostly still (minimal movement) and monitor "System Used Memory [MB]" continuously over an extended session (20+ minutes, reporter indicates the effect becomes clear well beyond that)

✔️ Expected Result:

System Used Memory stabilizes/plateaus after initial scene and asset load, fluctuating within a normal range without trending upward indefinitely.

❌ Actual Result with evidence:

• Pejo: memory consumption increases continuously while standing still with ~5 users on the Plaza; crashes/random bugs occur once the budget threshold is reached. Same scene on dclexperience is stable by comparison.
• QA screenshots (Virginia, same M3 Pro machine, same day) show two very different System Used Memory readings: 6941 MB and 12167 MB (Memory Budget Threshold 12902/13824 MB). Note: these two screenshots could not be reliably tied to a single continuous session from the timestamps available, so they're supporting evidence, not a confirmed before/after of one session.
• QA's own ~20-minute monitored session on v0.157.0-alpha-main stayed stable in the 6800–6900 MB range and did not reproduce a drastic increase.
• Known context: Genesis Plaza already has a standing performance issue (low FPS, max ~51 FPS at Medium settings in QA's session), which independently consumes memory/resources and may be a confound.

➗ Reproduction:

❓ Unknown - Reporter states 10/10 reproducibility over an extended session; QA was unable to reproduce a drastic increase in a ~20 minute session on the same build/hardware. Longer-duration testing (30–60+ min) with periodic memory logging is needed to confirm.

🖥️ Operative system and additional Notes:

• Mac M3 Pro (both reporter and QA), 18 GB RAM

Pejo

Player (Pejo).log

Virginia

Player (Vir).log

[github-actions]

Automated Triage

Issue type	bug
Affected area	Genesis Plaza (Primary) + Memory/Stability
Feature category	Primary
Severity	SEV-2 → 1-high

Reasoning: Genesis Plaza is a Primary category feature (line 74–78 of issue-triage-categories.md). The issue reports unbounded memory growth causing crashes when the memory budget is exceeded, affecting a subset of users (reporter + M3 Pro hardware). Per the "Excessive Resource Usage" table (lines 110–111), this is SEV-2: affects a subset of users with a memory leak that causes severe impact (crashes/random bugs). The current 3-low label underestimates the severity.

Labels applied: bug, 1-high, Mac Only, memory-issue, performance, qa-team

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Auto-triaged. If labels are incorrect, update issue triage categories or severity policy and re-run triage.

[decentraland-bot]

Update: Scene Distance implicated as major contributing factor

Follow-up investigation later the same day surfaced a strong lead:

• Omar's Scene Distance debug setting (scene loading radius) was at 100.
• After 15 min standing still it climbed 5600→6700 MB (consistent with the original report). A short tour of the plaza (clocktower → elevator → secret pool → back to spawn) then spiked memory from ~6700 MB to the ~12000 MB limit in under a minute, even though all assets were already loaded/rendered. The identical round trip on dclexperience.dcl.eth (same scene code/systems) stayed stable at ~5500 MB.
• Juan asked Omar to lower Scene Distance to 5 (the minimum) and repeat the test in Genesis Plaza.
• Result: memory was much more stable with Scene Distance = 5.

This points at the number of concurrently-loaded/fetched nearby scenes (driven by Scene Distance) as a major contributing factor — not just something intrinsic to the Genesis Plaza scene itself.

Open question for investigation (raised by Juan)

Is the growth caused by:

1. The increasing count of fetched/loaded nearby scenes as Scene Distance grows (general scaling problem), or
2. A specific scene near Genesis Plaza that is itself leaking/consuming a disproportionate amount of memory?

Suggested isolation approach: test Scene Distance=100 while excluding/identifying specific neighboring scenes around Genesis Plaza, or test the same high Scene Distance in an area with no unusual neighboring scenes, to separate "more scenes loaded" from "one bad scene."

Minor unconfirmed note: in Omar's original video the theatre screen at the Plaza had no video playing — possibly unrelated, flagging for completeness.

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Requested by Juan Ignacio Molteni (<@U03JSUQ5Z7U>)

[balducciv]

I confirm that if I max Scene Distance and Landscape Distance the memory keeps on going higher and higher

This thread has the discussion for reference