3 ms·

Microsoft`s Open Source Subsidiary Releases First Deliverable (Redis)

32 points by ks 14y ago

pragmatic 14y ago
This is good news, I've been waiting for the MS supported version of Redis so I can play with it on a Windows box. I wonder why they hosted on Github vs Codeplex. Codeplex supports Mercurial, Team Foundation Server or Subversion and Git. Microsoft recently posted the source for _parts_ of ASP.NET (minus web forms) on codeplex. (just curious, not trying to troll.)
- Meai 14y ago
  They are trying to garner good will from the community, it's only logical that they choose whatever is most popular right now.
- barranger 14y ago
  I'm pretty sure it's a case of Codeplex is going through a massive overhaul[1]. The addition of git support seems to be the first step. [1] here's a preview of the new look they are moving to: http://blogs.msdn.com/b/codeplex/archive/2012/03/30/new-codeplex-ui-coming-soon.aspx http://blogs.msdn.com/b/codeplex/archive/2012/03/30/new-code...
- kijin 14y ago
  Redis is hosted on Github. Most users of Redis are on Github, too. So if MS wants to exchange code back and forth between their fork and the original, it makes sense to host their code on Github, too. A pull request is much more friendly than "Hey, check out my Codeplex", even if antirez decides not to merge the changes.
- deleted 14y ago
  [deleted]
wickedchicken 14y ago
> "Redis on Linux uses an OS feature called Fork/Copy On Write. This feature is not available on Windows, The memory-mapped file APIs on Windows are seriously lacking. Last time I dealt with them, there was no documented way to write to a constantly-growing mmaped file (unless you knew its size already). All the workarounds I tried ended in segfaults :/. Curious if anyone here has had success with that.
- beagle3 14y ago
  How do you do that on Unix / Linux? Don't you have to set the size when you map the file?
  - wickedchicken 14y ago
    You can change the size of the allocation on the fly, and just keep writing bytes as you go. Pages aren't alloc'd on disk until they're touched. When you hit the end of the file, you call a final resize to trim off the virtual bytes at the end. You can see an example of the technique here: http://www.gnu.org/software/libc/manual/html_node/File-Size.html http://www.gnu.org/software/libc/manual/html_node/File-Size.... (scroll to the bottom).
    - beagle3 14y ago
      > You can change the size of the allocation on the fly, and just keep writing bytes as you go. How do you do this technically? mremap(), I assume? You can do something very similar on windows, by VirtualAlloc()ing at the end of the previous allocation, and if that fails, be committing, VirtualFreeing and remapping at a different address. Yes, I agree mremap() is much cleaner. I am mostly a Linux guy myself. What I'm missing in Linux is "mremap2()", which would map an existing block of memory onto a file (whereas mmap maps an existing file onto a block of memory ). redis achieves similar functionality (and more) by fork()ing and write()ing instead, but it would be nicer if it could be done with one call and no fork()ing. a "copy this file from here to here" could then be done by mmap()ing the source into memory, mremap2()ing the memory into the destination file, and forgetting about it. added: This would also allow btrfs/zfs to have O(1) file copy, even between independent media if possible (i.e. source file already exists on target media, even if in a different directory) - without any consideration from the cp implementation.

32 points by ks 14y ago

This is good news, I've been waiting for the MS supported version of Redis so I can play with it on a Windows box. I wonder why they hosted on Github vs Codeplex. Codeplex supports Mercurial, Team Foundation Server or Subversion and Git. Microsoft recently posted the source for _parts_ of ASP.NET (minus web forms) on codeplex. (just curious, not trying to troll.)

Meai 14y ago
They are trying to garner good will from the community, it's only logical that they choose whatever is most popular right now.
barranger 14y ago
I'm pretty sure it's a case of Codeplex is going through a massive overhaul[1]. The addition of git support seems to be the first step. [1] here's a preview of the new look they are moving to: http://blogs.msdn.com/b/codeplex/archive/2012/03/30/new-codeplex-ui-coming-soon.aspx http://blogs.msdn.com/b/codeplex/archive/2012/03/30/new-code...
kijin 14y ago
Redis is hosted on Github. Most users of Redis are on Github, too. So if MS wants to exchange code back and forth between their fork and the original, it makes sense to host their code on Github, too. A pull request is much more friendly than "Hey, check out my Codeplex", even if antirez decides not to merge the changes.
deleted 14y ago
[deleted]

wickedchicken 14y ago

> "Redis on Linux uses an OS feature called Fork/Copy On Write. This feature is not available on Windows, The memory-mapped file APIs on Windows are seriously lacking. Last time I dealt with them, there was no documented way to write to a constantly-growing mmaped file (unless you knew its size already). All the workarounds I tried ended in segfaults :/. Curious if anyone here has had success with that.

beagle3 14y ago
How do you do that on Unix / Linux? Don't you have to set the size when you map the file?
- wickedchicken 14y ago
  You can change the size of the allocation on the fly, and just keep writing bytes as you go. Pages aren't alloc'd on disk until they're touched. When you hit the end of the file, you call a final resize to trim off the virtual bytes at the end. You can see an example of the technique here: http://www.gnu.org/software/libc/manual/html_node/File-Size.html http://www.gnu.org/software/libc/manual/html_node/File-Size.... (scroll to the bottom).
  - beagle3 14y ago
    > You can change the size of the allocation on the fly, and just keep writing bytes as you go. How do you do this technically? mremap(), I assume? You can do something very similar on windows, by VirtualAlloc()ing at the end of the previous allocation, and if that fails, be committing, VirtualFreeing and remapping at a different address. Yes, I agree mremap() is much cleaner. I am mostly a Linux guy myself. What I'm missing in Linux is "mremap2()", which would map an existing block of memory onto a file (whereas mmap maps an existing file onto a block of memory ). redis achieves similar functionality (and more) by fork()ing and write()ing instead, but it would be nicer if it could be done with one call and no fork()ing. a "copy this file from here to here" could then be done by mmap()ing the source into memory, mremap2()ing the memory into the destination file, and forgetting about it. added: This would also allow btrfs/zfs to have O(1) file copy, even between independent media if possible (i.e. source file already exists on target media, even if in a different directory) - without any consideration from the cp implementation.