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I am thrilled to announce the arrival of a new stable version of Node.js.

Compared with the v0.6 releases of Node, this release brings significant improvements in many key performance metrics, as well as cleanup in several core APIs, and the addition of new debugging features.


With version 0.8.0:

  1. Node got a lot faster.
  2. Node got more stable.
  3. You can do stuff with file descriptors again.
  4. The cluster module is much more awesome.
  5. The domain module was added.
  6. The repl is better.
  7. Some other stuff changed, too.
  8. Scroll to the bottom for the links to install it.


This version brings a few key enhancements in V8 and libuv that result in significantly improved throughput.

All of these benchmarks were run on my OS X laptop, but the results are typical of what we're seeing on SmartOS, Linux, and Windows.

# io.js

# 0.6.19, writes
Wrote 1024 byte buffers: 19.428793471925395 mB/s
Wrote 4096 byte buffers: 59.737156511350065 mB/s
Wrote 16384 byte buffers: 83.97010664203543 mB/s
Wrote 65536 byte buffers: 97.4184120798831 mB/s

# 0.8.0, writes
Wrote 1024 byte buffers: 61.236987140232706 mB/s
Wrote 4096 byte buffers: 109.05125408942203 mB/s
Wrote 16384 byte buffers: 182.18254691200585 mB/s
Wrote 65536 byte buffers: 181.91740949608877 mB/s

# v0.6.19, reads
Read 1024 byte buffers: 29.96883241428914 mB/s
Read 4096 byte buffers: 62.34413965087282 mB/s
Read 16384 byte buffers: 165.7550140891762 mB/s
Read 65536 byte buffers: 266.73779674579885 mB/s

# v0.8.0, reads
Read 1024 byte buffers: 57.63688760806916 mB/s
Read 4096 byte buffers: 136.7801942278758 mB/s
Read 16384 byte buffers: 244.8579823702253 mB/s
Read 65536 byte buffers: 302.2974607013301 mB/s

The difference is not small. If you are writing network programs with node, and pushing a lot of traffic, you will notice this improvement.

The speed of reading files got quite a bit faster as well:

# v0.6.19
read the file 110948 times (higher is better)
90141.32 ns per read (lower is better)
11093.69 reads per sec (higher is better)

# v0.8.0
read the file 158193 times (higher is better)
63217.16 ns per read (lower is better)
15818.48 reads per sec (higher is better)

And of course, the ubiquitous 'hello, world' http server benchmark got significantly faster, especially for large message sizes:

$ TYPE=bytes LENGTH=123 bash benchmark/  2>&1 | grep Req
# 0.6.19
Requests per second:    3317.24 [#/sec] (mean)
# 0.8.0
Requests per second:    3795.34 [#/sec] (mean)

$ TYPE=bytes LENGTH=1024 bash benchmark/  2>&1 | grep Req
# v0.6.19
Requests per second:    3258.42 [#/sec] (mean)
# 0.8.0
Requests per second:    3585.62 [#/sec] (mean)

$ TYPE=bytes LENGTH=123456 bash benchmark/  2>&1 | grep Req
# v0.6.19
Requests per second:    218.51 [#/sec] (mean)
# 0.8.0
Requests per second:    749.17 [#/sec] (mean)

The difference with Unicode responses is even more pronounced:

$ TYPE=unicode LENGTH=1024 bash benchmark/  2>&1 | grep Req
# v0.6.19
Requests per second:    3228.23 [#/sec] (mean)
# v0.8.0
Requests per second:    3317.60 [#/sec] (mean)

$ TYPE=unicode LENGTH=12345 bash benchmark/  2>&1 | grep Req
# v0.6.19
Requests per second:    1703.96 [#/sec] (mean)
# v0.8.0
Requests per second:    2431.61 [#/sec] (mean)

$ TYPE=unicode LENGTH=55555 bash benchmark/  2>&1 | grep Req
Requests per second:    161.65 [#/sec] (mean)
Requests per second:    980.38 [#/sec] (mean)

$ TYPE=unicode LENGTH=99999 bash benchmark/  2>&1 | grep Req
# v0.6.19
^C  # lost patience after a few hours
# v0.8.0
Requests per second:    252.69 [#/sec] (mean)

The more bytes you're pushing, and the more work you're doing, the more win you'll see with node 0.8 over 0.6.

The vast majority of the performance boost is due to improvements in V8. They've been very responsive to the needs of the Node.js project. A lot of Node's success is due to being built on such a stellar VM.


The transition from libev and libeio to libuv in 0.6 was somewhat destabilizing for many node internals. The gambit paid off: libuv is the obvious choice in cross-platform asynchronous IO libraries, and Node.js is impressively performant on both Windows and Unix. But it made the transition from 0.4 to 0.6 was very rocky for a lot of users. Libuv wasn't as mature as node, and it showed in those early releases.

At this point, with very few exceptions, if your v0.6 program doesn't run on v0.8, it should be easy and obvious to make whatever changes are necessary. Libuv has come a very long way, and Node 0.8 is a simpler and more efficient machine as a result.

See the migration wiki for details on the specific APIs that changed.

The Return of File Descriptors

In Node 0.4, there was a listenFD method that servers could use to listen on a specific file descriptor that was already bound to a socket or port. In 0.6, that functionality went away, largely because it was very Unix-specific, and couldn't be easily made to work with the new cross-platform libuv base.

Since the most common use case for listenFD was as a method for having servers in multiple node processes share the same underlying handle, the cluster module was added in its place. However, this still left a lot of use cases unaddressed, and was a reason why some people could not use node 0.6 for their programs.

In 0.8, we've replaced this functionality, as server.listen({ fd: number }).

The other feature in node 0.4 that got dropped in 0.6 was the ability to pass arbitrary file descriptors as a child process's stdio, using the customFds array. In Node 0.6, customFds could be used to inherit the parent's stdio handles, but not to pass arbitrary handles or file descriptors to the child's stdio. Also, there was never a way to pass more than the standard in, out, err trio, so programs that expected FD 4 to be opened in some specific way were out of luck.

In 0.8, we've added the stdio array on the child_process.spawn options. Pass as many file descriptors, handles, etc. as you like, and the child process will see them as already-opened FDs.

More Powerful Cluster

The cluster module in 0.8 is so much improved over 0.6, it's basically a complete rewrite. The API is mostly backwards compatible, but not entirely. (See the migration wiki for details.)

Barring these very minor API changes, if you were using cluster in 0.6, then your program will still work, but it'll be faster and more well-behaved now. And if you aren't taking advantage of the new features in 0.8's cluster, you're really missing out.

There's too much even to do it justice here. Go read the API docs.


The original idea for Domains was a way to join multiple different IO actions, so that you can have some context when an error occurs.

Since Ryan discussed the feature with node users at NodeConf Summer Camp last year, the domains feature has gone through many revisions. The problem is fairly well understood, but most attempts to solve it resulted in serious performance regressions, or uncovered difficult edge cases.

What we ended up with in 0.8 is a very stripped-down version of this idea. It's entirely opt-in, with minimal performance impact when it's used (and none when it isn't). There are a lot of examples in the API documentation, so check them out, and start handling your crashes smarter.

The domain module is still experimental. We are looking forward to your feedback, so please use it and let us know what you think.

Repl, Readline, TTY

The Repl, Readline, and TTY modules have all had a major facelift. The interfaces between these three modules are cleaned up and refactored, removing a lot of common pain points and making it easier to use for debugging your programs.

It may seem minor at times, but a good repl dramatically increases the quality of the overall experience. My personal favorites are:

  1. Typing fs or net or path will automatically load the module.
  2. Typing npm install ... will give you a helpful message.
  3. It doesn't do that stupid thing where long lines wrap and then the backspace makes it get all confused and crazy. Instead of that, it does the right thing.

Looking Forward

Like other even-numbered version families before it, v0.8 will maintain API and ABI stability throughout its lifetime.

The v0.6 release family will continue to see releases for critical bugfixes and security issues through the end of 2012. However, it will not be the main focus of the core team's attention.

The v0.9 releases will start in the next couple weeks. The main focus of v0.9 will be:

  • The HTTP implementation - It has seen a lot of real-world use now, but the http module is in dire need of a cleanup and refactor. Special attention will be paid to making the interfaces more consistent, improve performance, and increase correctness in more edge cases.
  • The Streams API - The concept of the Stream API is very core to node. However, it is also (like HTTP) a feature that grew up organically, and is now in need of a cleanup. It is currently too hard to get right, especially regarding error handling.
  • Libuv Streams - The handle interfaces in libuv are going to be refactored for added consistency throughout the codebase and across platforms.

Looking past that, there are a few areas where Node.js still has room for improvement in terms of internal consistency, idiomatic JavaScript usage, and performance. None of these are fully-fleshed out ideas yet, but these are some of the items on our radar:

  • We ought to move to TypedArrays in favor of Buffers. Buffers will continue to work, but since TypedArray is a JavaScript native, it makes sense to move towards that as the preferred API.
  • SSL performance leaves much to be desired at the moment. Node's interface with OpenSSL is somewhat naive and leaves a lot of potential optimization on the table.
  • The VM module needs massive improvement. It lacks features required to emulate a web browser JavaScript context, which means that it is inadequate.
  • The Crypto module still uses some very dated APIs. In 0.8, it can accept Buffers for many things (finally!) but it still does not present a Node-like streaming interface.

At this point, the scope of Node's feature set is pretty much locked down. We may move things around internally for these cleanup tasks, but as you can see, there are no major new features planned. We've drawn our boundaries, and now it's time to continue focusing on improving stability and performance of the core, so that more innovation can happen in your programs.

And now, for those of you who may be wondering what was added since v0.7.12, your regularly scheduled release announcement:

2012.06.25, Version 0.8.0 (stable)

  • V8: upgrade to v3.11.10.10

  • npm: Upgrade to 1.1.32

  • Deprecate iowatcher (Ben Noordhuis)

  • windows: update icon (Bert Belder)

  • http: Hush 'MUST NOT have a body' warnings to debug() (isaacs)

  • Move content into repository (isaacs)

  • Fix #3503: stdin: resume() on pipe(dest) (isaacs)

  • crypto: fix error reporting in SetKey() (Fedor Indutny)

  • Add --no-deprecation and --trace-deprecation command-line flags (isaacs)

  • fs: fix fs.watchFile() (Ben Noordhuis)

  • fs: Fix fs.readfile() on pipes (isaacs)

  • Rename GYP variable node_use_system_openssl to be consistent (Ryan Dahl)

Source Code:

Macintosh Installer (Universal):

Windows Installer:

Windows x64 Installer:

Windows x64 Files:

Other release files:




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AndreasMadsen commented Jun 22, 2012

If you were using cluster in 0.6, then your program will still work, but it'll be faster and more well-behaved now.

@isaacs the cluster module is not backward compatible.

however replaceing cluster.fork() with cluster.fork().process and cluster.on('death', fn) with cluster.on('exit', fn) should do it. But you will loss many advantages.


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koichik commented Jun 23, 2012


# v0.8.0, writes
Read 1024 byte buffers: 57.63688760806916 mB/s



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isaacs commented Jun 23, 2012

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