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Memory leak: 14K ArrayBuffers accumulate from streaming responses (~480 MB/hour) #32920
Description
Description
Claude Code accumulates ArrayBuffer objects over time, leading to significant memory growth. After ~14.5 hours of uptime, the process consumed ~7 GB of RAM with a steady growth rate of ~480 MB/hour.
Environment
- Claude Code version: 2.1.71
- Node.js: v24.3.0
- Platform: Linux (Ubuntu 22.04, WSL2, x86_64)
Heap Dump Analysis
Captured a V8 heap snapshot (/heapdump) and diagnostics JSON. Key findings:
Memory Breakdown
| Metric | Value |
|---|---|
| RSS | 6.9 GB |
| V8 Heap (JS objects) | 70 MB |
| External/Native memory | 7.56 GB |
| ArrayBuffers | 6.83 GB |
| Growth rate | 478.6 MB/hour |
| Uptime at capture | ~14.5 hours |
Heap Snapshot Object Breakdown
| Object Type | Count | Aggregate Size |
|---|---|---|
ArrayBuffer |
14,002 | 6,512 MB |
Response (native HTTP) |
2 | 446 MB |
Uint8Array (views) |
14,228 | ~2 MB (metadata) |
Blob (native) |
~5 | ~7 MB |
| All other JS objects | ~640K | ~57 MB |
The V8 JS heap itself is tiny (70 MB). Nearly all memory is in external/native allocations backing ArrayBuffer objects.
Pattern
- ~14,000 ArrayBuffers, mostly 0.5 MB each, with a few at 16-32 MB
- Two retained native
Responseobjects at 223 MB each (HTTP API responses) - 14,228
Uint8Arrayviews corresponding to the ArrayBuffers - Growth rate of ~16 new 0.5 MB buffers per minute, consistent with streaming API token delivery
Diagnostics JSON Summary
{
"memoryUsage": {
"heapUsed": 7613741617,
"heapTotal": 70292480,
"external": 7562328657,
"arrayBuffers": 6829807179,
"rss": 7256211456
},
"memoryGrowthRate": {
"bytesPerSecond": 139398.6,
"mbPerHour": 478.6
},
"analysis": {
"potentialLeaks": ["High memory growth rate: 478.6 MB/hour"]
}
}Likely Cause
Streaming API response chunks (ArrayBuffers) and/or their backing native Response objects are not being released after consumption. The steady linear growth rate and uniform ~0.5 MB buffer size point to per-chunk allocations from the Anthropic API streaming responses that are retained indefinitely.
Workaround
Restart Claude Code periodically (every few hours) to reclaim memory.
Activity
kevin-tcircuits commentedon Mar 10, 2026
Possible Duplicates
This appears to be a widely reported issue on v2.1.71. Related reports with the same ArrayBuffer accumulation pattern:
Responseobjects seen in this dumpOlder related reports:
This issue's heap snapshot data (14K x 0.5 MB ArrayBuffers + 2x 223 MB retained native Response objects) may help pinpoint the specific retention path.
TweedBeetle commentedon Mar 12, 2026
Adding a finding from independent heap snapshot analysis (v2.1.72, Node v24.3.0, macOS) that may point to a separate, smaller leak:
Unconsumed HTTP Response retained by pending Promise chain (181 MB)
A single
native::Responseobject (181.59 MB) is kept alive by an unconsumed stream whoseonendcallback never fires:This is distinct from the ArrayBuffer accumulation -- it's a single HTTP response body that was never fully consumed/drained, so the stream holds the entire body in memory indefinitely via a pending Promise.
Additionally, 46
Readablestreams holdremainingChunkreferences to Uint8Array views backed by leaked ArrayBuffers, confirming the stream/transport origin of the main leak:Closed #33570 in favor of this issue.
github-actions commentedon Apr 10, 2026
Closing for now — inactive for too long. Please open a new issue if this is still relevant.
github-actions commentedon Apr 18, 2026
This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.