Merge lp://staging/~mbp/bzr/remove-pylzma into lp://staging/bzr

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Re-adding my comment, because lp rejected my non-signed email:
 merge: approve

There were some interesting benefits from it, but since it isn't officially part of the 2a format, we certainly don't want to accidentally use it.

Specifically:

1) lzma was very slow (~10x slower than zlib) when the data was not well delta-packed to start with (eg, initial commit, lots of fulltexts, etc). It did generate smaller content.
2) lzma was only a little bit slower and a little bit smaller when the data had good delta-compression ('bzr pack' time). IIRC, 30% smaller for ~30% more overhead.
3) lzma was a little bit slower to extract.
4) lzma bindings weren't trivial to get, though with xz being more standard now, that might be easier.
5) I didn't do memory profiling for lzma vs zlib. My guess it would be a fair amount worse for compression, a little bit worse for extraction.

In the end, lzma made a lot of sense for old data that isn't accessed much, and would already have a pretty good delta-compression chain. Which would be really nice for archived content.

We can certainly put it in the 'interesting, but not yet worth it' pile.

John
=:->

26 elif self._compressor_name == 'lzma':
27 # We don't do partial lzma decomp yet
28 + import pylzma
29 self._content = pylzma.decompress(z_content)

Did you plan to remove this chunk and forgot ?

Bah, sorry for the noise, got confused by the cover letter but the commit message is clear.

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I keep wondering why I'm not getting the PQM failure emails for this. Are they sent to Martin only ?

I am not getting any failure mails. I will send it now.

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pylzma refuses to die. Mwuahahahahahahahahaaaaa!

John
=:->
On Nov 16, 2011 1:40 AM, "Martin Pool" <email address hidden> wrote:

> I am not getting any failure mails. I will send it now.
>
> --
> https://code.launchpad.net/~mbp/bzr/remove-pylzma/+merge/82097
> You are reviewing the proposed merge of lp:~mbp/bzr/remove-pylzma into
> lp:bzr.
>

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something is wrong, apparently specific to this branch. I will look into it
tomorrow.
On Nov 17, 2011 8:53 PM, "Jelmer Vernooij" <email address hidden> wrote:

> sent to pqm by email
>
> --
> https://code.launchpad.net/~mbp/bzr/remove-pylzma/+merge/82097
> You are the owner of lp:~mbp/bzr/remove-pylzma.
>
>

So John was right, this branch *is* haunted. I will stop submitting it
to PQM then :-)

Cheers,

Jelmer

Am Thu 17 Nov 2011 12:02:51 CET schrieb Martin Pool:
> something is wrong, apparently specific to this branch. I will look into it
> tomorrow.
> On Nov 17, 2011 8:53 PM, "Jelmer Vernooij" <email address hidden> wrote:
>
>> sent to pqm by email
>>
>> --
>> https://code.launchpad.net/~mbp/bzr/remove-pylzma/+merge/82097
>> You are the owner of lp:~mbp/bzr/remove-pylzma.
>>
>>
>

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