readStreams leaking in Node

100%

readStreams leaking in Node

✓ Published0🌍 Public

Last edited Jun 25, 2013

Created on Jun 25, 2013

This animation shows memory leaking in a Node.js process as it repeatedly creates read streams for a 2 MB file. Over 180 streams are spawned in a loop, each printing characters to indicate lifecycle events ('o' on open, '*' on data, '$' on end). Every 5 seconds, the script forces garbage collection via `--expose-gc` and logs the process’s resident set size (RSS) in megabytes, producing a stepwise upward trend that reveals how unclosed stream handlers accumulate and prevent memory from being reclaimed. The visualization renders this growth as an animated time series, highlighting the leak’s progression over time.

AI-generated description

Similar vizzes

Loading thumbnail…

Node read stream

This example streams the contents of a server log file directly to the browser as an HTTP response. It uses Node.js’s `fs.createReadStream` to read the file with UTF-8 encoding, then listens to the `'data'` event to strip newline characters and send each chunk via `res.send`. The code does not perform any visual rendering or charting; instead, it demonstrates a raw data-delivery pattern where log entries are pushed to the client in real time as they are read. No visualization library is involved.

Aalessioalex

61% match

Loading thumbnail…

custom-writable-stream.js

This example demonstrates a custom Writable stream in Node.js that stores incoming data in an in-memory object. It shows how to extend the `stream.Writable` class, using `util.inherits` to create the `WMStrm` constructor, which initializes a `Buffer` for a given key. The overridden `_write` method concatenates each chunk, whether already a `Buffer` or converted from a string, to the stored buffer. The code then writes two strings to the stream, triggers the `finish` event, and logs the accumulated result from the `memStore` object.

Aalessioalex

59% match

Loading thumbnail…

Memcached in JavaScript based on Node.JS

This example visualizes the behavior of a Memcached server implemented in Node.js, showing how it manages key-value storage with an LRU (Least Recently Used) eviction strategy under memory pressure. The animation displays the element count in the cache, updating every two seconds via a `setInterval` callback. The code uses Node.js `net` module for TCP networking, a custom LRU class based on chriso/lru, and leverages `process.memoryUsage()` to monitor RSS memory. It also exposes a custom `gc` command to trigger garbage collection via `gc()`.

Aalessioalex

59% match

Loading thumbnail…

d3-timer memory leak

This example demonstrates a memory leak in d3-timer by creating a timer that runs indefinitely with a 150-millisecond delay. The page loads the d3-timer library from a CDN and instantiates a timer via `d3.timer()`, passing an empty callback that executes on each tick. The visualization shows how a timer persists without explicit disposal, highlighting potential performance issues in long-running applications. The code uses plain HTML and JavaScript with no rendering, making the leak’s behavior visible through browser developer tools rather than visual output.

CCurran Kelleher

57% match

Loading thumbnail…

Streamgraph

This example demonstrates a streamgraph with 20 layers and 200 samples per layer, where the layers smoothly transition between two different datasets when the "Update" button is clicked. The visualization uses color-coded stacked areas that wiggle and morph over a 1.5-second duration, with hover interactions fading non-target layers. Built with d3.v2, it relies on the `d3.layout.stack` with the "wiggle" offset, `d3.svg.area` for rendering paths, and `d3.interpolateRgb` for color generation. Data is procedurally generated via the `stream_layers` function, and rendering uses SVG with custom transitions.

GGerHobbelt

56% match

Loading thumbnail…

Gist c53b34b249207da31466

This animated visualization is a Node.js cheat sheet that displays API documentation in a dynamic, moving format. The code covers fundamental Node.js concepts including global objects, console methods, timers, modules, and process handling. It demonstrates the use of the http module to create a web server and various event-driven programming techniques. The animation renders the documentation in a visually engaging way, showcasing both the syntax and usage of core Node.js APIs.

SSwampGuzzler

56% match

Loading thumbnail…

Syndrom: FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - process out of memory

This visualization maps the memory-allocation failure message from an `npm search` command, using a force-directed graph with `d3.forceSimulation` to layout nodes representing the error text, the Node.js executable path, and the suggested `--max_old_space_size` workaround. It renders the raw terminal output and the fix command as linked text elements, with node positions computed by simulated physics. The data comes from a gist by ThomasG77, and the visualization applies `d3.forceLink` and `d3.forceManyBody` to show relationships between the error symptom, the NVM environment, and the memory-tweaking solution.

TThomasG77

55% match

Loading thumbnail…

Gist 597373

This example shows a Node.js script that attempts to process crime incident data from a CSV file using the `ecsv` library, but it fails due to a system resource limit. The code calls `exec('wc -c "foo"', ...)` inside the `ecsv.each` callback for every row, spawning a new child process for each record. The visible stack trace from `child_process.spawn` reveals the error "Too many open files," indicating the script exhausts file descriptors because it launches processes asynchronously without waiting for completion. The gist demonstrates a common anti-pattern where unthrottled asynchronous process spawning overwhelms the operating system, using only Node.js core APIs (`child_process.exec`, `fs`) and the third-party `ecsv` parser.

CCaged

55% match