MemoryError

[Angel Ezquerra]

On Mon, Nov 5, 2012 at 9:48 PM, Matt Mackall <mpm at selenic.com> wrote:
> On Mon, 2012-11-05 at 16:35 +0100, Angel Ezquerra wrote:
>> Hi,
>>
>> a colleague of mine just had a problem when committing a pretty large
>> binary file (260 MB). At first he was not able to commit (hg returned error
>> code 255). In the end he was able to successfully commit (I believe he
>> created a brand new repository and tried again). However, now he is not
>> able to update to that revision.
>>
>> Running "hg verify --verbose" returns:
>>
>>     C:\scb\prueba>hg verify --verbose
>>     repository uses revlog format 1
>>     checking changesets
>>     checking manifests
>>     crosschecking files in changesets and manifests
>>     checking files
>>     MCRInstaller.exe at 0: unpacking 63e2441ad980: MemoryError()
>>     12 files, 1 changesets, 12 total revisions
>>     1 integrity errors encountered!
>>     (first damaged changeset appears to be 0)
>>
>> Apparently mercurial is unable to unpack the file due to memory problems.
>
> Yep.
>
>> His PC is running WindowsXP 32bit, and it only has 2 GB of ram. However the
>> Windows Task Admin shows that he has 1.13 GB free (I attach a picture
>> showing it, but it is in Spanish. "Disponible" means "Available").
>>
>> [image: Inline image 1]
>>
>> Does this error make sense? I believed that mercurial needed twice as much
>> free memory as the size of the biggest file. If that is the case it seems
>> that is computer should have enough memory to handle this file.
>
> Mercurial itself uses _3x_ in its warning on large files. That number is
> pretty solid for small files, but it turns out to be fairly optimistic
> on the large end, due to the implementation details of the platform's
> memory allocators and virtual address space fragmentation. So, no, I
> can't say I'm surprised this didn't work.
>
>
> Consider enabling swap. Then expect to run into further difficulties at
> file sizes around 400MB that can only be fixed by moving to 64-bit (or
> Linux).

Thank you Matt,

I just checked my colleague's "Virtual Memory" configuration and it
has set it up to use a "Custom" page file size. He has it configured
to have an initial size "Paging File" of 2046 MB and a maximum size of
4092 MB.

I believe that means he already has swap enabled?

If that is the case, it seems that our only option is to use largefiles.

Cheers,

Angel