<div dir="ltr">OK. It tells me the same error message in popup, but all the projections are running after that. <div><br></div><div style>I'll make sure that it does not say any strange errors on empty DB in new version. </div>
<div style><br></div><div style>Does it start projections for you as well (even if it says error)?</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Tue, Jan 8, 2013 at 1:00 PM, <span dir="ltr"><<a href="mailto:haskell-cafe-request@haskell.org" target="_blank">haskell-cafe-request@haskell.org</a>></span> wrote:<br>
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<br>Today's Topics:<br>
<br>
1. Example programs with ample use of deepseq? (Joachim Breitner)<br>
2. Re: Example programs with ample use of deepseq? (Edward Z. Yang)<br>
3. Re: Example programs with ample use of deepseq? (Joachim Breitner)<br>
4. Re: Example programs with ample use of deepseq? (Johan Tibell)<br>
5. Re: Announce: Leksah 0.13.1 (a bit experimental) (Peter Simons)<br>
6. Re: Announce: Leksah 0.13.1 (a bit experimental)<br>
(Hamish Mackenzie)<br>
<br><br>---------- Forwarded message ----------<br>From: Joachim Breitner <<a href="mailto:mail@joachim-breitner.de">mail@joachim-breitner.de</a>><br>To: Haskell Cafe <<a href="mailto:haskell-cafe@haskell.org">haskell-cafe@haskell.org</a>><br>
Cc: <br>Date: Mon, 07 Jan 2013 13:06:35 +0100<br>Subject: [Haskell-cafe] Example programs with ample use of deepseq?<br>Dear Haskellers,<br>
<br>
I’m wondering if the use of deepseq to avoid unwanted lazyness might be<br>
a too large hammer in some use cases. Therefore, I’m looking for real<br>
world programs with ample use of deepseq, and ideally easy ways to test<br>
performance (so preferably no GUI applications).<br>
<br>
I’ll try to find out, by runtime observerations, which of the calls ot<br>
deepseq could be replaced by id, seq, or „shallow seqs“ that, for<br>
example, calls seq on the elements of a tuple.<br>
<br>
Thanks,<br>
Joachim<br>
<br>
--<br>
Joachim "nomeata" Breitner<br>
<a href="mailto:mail@joachim-breitner.de">mail@joachim-breitner.de</a> | <a href="mailto:nomeata@debian.org">nomeata@debian.org</a> | GPG: 0x4743206C<br>
xmpp: <a href="mailto:nomeata@joachim-breitner.de">nomeata@joachim-breitner.de</a> | <a href="http://www.joachim-breitner.de/" target="_blank">http://www.joachim-breitner.de/</a><br>
<br>
<br><br>---------- Forwarded message ----------<br>From: "Edward Z. Yang" <<a href="mailto:ezyang@MIT.EDU">ezyang@MIT.EDU</a>><br>To: Joachim Breitner <<a href="mailto:mail@joachim-breitner.de">mail@joachim-breitner.de</a>><br>
Cc: Haskell Cafe <<a href="mailto:haskell-cafe@haskell.org">haskell-cafe@haskell.org</a>><br>Date: Mon, 07 Jan 2013 04:20:43 -0800<br>Subject: Re: [Haskell-cafe] Example programs with ample use of deepseq?<br>There are two senses in which deepseq can be overkill:<br>
<br>
1. The structure was already strict, and deepseq just forces another<br>
no-op traversal of the entire structure. This hypothetically affects<br>
seq too, although seq is quite cheap so it's not a problem.<br>
<br>
2. deepseq evaluates too much, when it was actually sufficient only to<br>
force parts of the structure, e.g. the spine of a list. This is less<br>
common for the common use-cases of deepseq; e.g. if I want to force pending<br>
exceptions I am usually interested in all exceptions in a (finite) data<br>
structure; a space leak may be due to an errant closure---if I don't<br>
know which it is, deepseq will force all of them, ditto with work in<br>
parallel programs. Certainly there will be cases where you will want snip<br>
evaluation at some point, but that is somewhat difficult to encode<br>
as a typeclass, since the criterion varies from structure to structure.<br>
(Though, perhaps, this structure would be useful:<br>
<br>
data Indirection a = Indirection a<br>
class DeepSeq Indirection<br>
rnf _ = ()<br>
)<br>
<br>
Cheers,<br>
Edward<br>
<br>
Excerpts from Joachim Breitner's message of Mon Jan 07 04:06:35 -0800 2013:<br>
> Dear Haskellers,<br>
><br>
> I’m wondering if the use of deepseq to avoid unwanted lazyness might be<br>
> a too large hammer in some use cases. Therefore, I’m looking for real<br>
> world programs with ample use of deepseq, and ideally easy ways to test<br>
> performance (so preferably no GUI applications).<br>
><br>
> I’ll try to find out, by runtime observerations, which of the calls ot<br>
> deepseq could be replaced by id, seq, or „shallow seqs“ that, for<br>
> example, calls seq on the elements of a tuple.<br>
><br>
> Thanks,<br>
> Joachim<br>
><br>
<br>
<br>
<br><br>---------- Forwarded message ----------<br>From: Joachim Breitner <<a href="mailto:mail@joachim-breitner.de">mail@joachim-breitner.de</a>><br>To: <a href="mailto:haskell-cafe@haskell.org">haskell-cafe@haskell.org</a><br>
Cc: <br>Date: Mon, 07 Jan 2013 16:59:45 +0100<br>Subject: Re: [Haskell-cafe] Example programs with ample use of deepseq?<br>Hi,<br>
Am Montag, den 07.01.2013, 13:06 +0100 schrieb Joachim Breitner:<br>
> I’m wondering if the use of deepseq to avoid unwanted lazyness might be<br>
> a too large hammer in some use cases. Therefore, I’m looking for real<br>
> world programs with ample use of deepseq, and ideally easy ways to test<br>
> performance (so preferably no GUI applications).<br>
<br>
surprisingly, deepseq is not used as much as I thought.<br>
<a href="http://packdeps.haskellers.com/reverse/deepseq" target="_blank">http://packdeps.haskellers.com/reverse/deepseq</a> lists a lot of packages,<br>
but (after grepping through some of the code) most just define NFData<br>
instances and/or use it in tests, but rarely in the „real“ code. For<br>
some reason I expected it to be in more widespread use.<br>
<br>
But therefore I am even more interested in non-hackaged applications<br>
that I can be allowed to stud – in return I might be able to tell you<br>
way to speed up your application.<br>
<br>
Greetings,<br>
Joachim<br>
<br>
--<br>
Joachim "nomeata" Breitner<br>
<a href="mailto:mail@joachim-breitner.de">mail@joachim-breitner.de</a> | <a href="mailto:nomeata@debian.org">nomeata@debian.org</a> | GPG: 0x4743206C<br>
xmpp: <a href="mailto:nomeata@joachim-breitner.de">nomeata@joachim-breitner.de</a> | <a href="http://www.joachim-breitner.de/" target="_blank">http://www.joachim-breitner.de/</a><br>
<br>
<br><br>---------- Forwarded message ----------<br>From: Johan Tibell <<a href="mailto:johan.tibell@gmail.com">johan.tibell@gmail.com</a>><br>To: Joachim Breitner <<a href="mailto:mail@joachim-breitner.de">mail@joachim-breitner.de</a>><br>
Cc: Haskell Cafe <<a href="mailto:haskell-cafe@haskell.org">haskell-cafe@haskell.org</a>><br>Date: Mon, 7 Jan 2013 08:12:31 -0800<br>Subject: Re: [Haskell-cafe] Example programs with ample use of deepseq?<br>On Mon, Jan 7, 2013 at 4:06 AM, Joachim Breitner<br>
<<a href="mailto:mail@joachim-breitner.de">mail@joachim-breitner.de</a>> wrote:<br>
> I’m wondering if the use of deepseq to avoid unwanted lazyness might be<br>
> a too large hammer in some use cases. Therefore, I’m looking for real<br>
> world programs with ample use of deepseq, and ideally easy ways to test<br>
> performance (so preferably no GUI applications).<br>
<br>
I never use deepseq, except when setting up benchmark data where it's<br>
a convenient way to make sure that the data is evaluated before the<br>
benchmark is run.<br>
<br>
When removing space leaks you want to avoid creating the thunks in the<br>
first place, not remove them after the fact. Consider a leak caused by<br>
a list of N thunks. Even if you deepseq that list to eventually remove<br>
those thunks, you won't lower your peak memory usage if the list was<br>
materialized at some point.<br>
<br>
In addition, by not creating the thunks in the first place you avoid<br>
some allocation costs.<br>
<br>
-- Johan<br>
<br>
<br>
<br><br>---------- Forwarded message ----------<br>From: Peter Simons <<a href="mailto:simons@cryp.to">simons@cryp.to</a>><br>To: <a href="mailto:haskell-cafe@haskell.org">haskell-cafe@haskell.org</a><br>Cc: <a href="mailto:gtk2hs-devel@lists.sourceforge.net">gtk2hs-devel@lists.sourceforge.net</a><br>
Date: Mon, 07 Jan 2013 19:25:22 +0100<br>Subject: Re: [Haskell-cafe] Announce: Leksah 0.13.1 (a bit experimental)<br>Hi Hamish,<br>
<br>
would it be possible to get an update for process-leksah that works with<br>
recent versions of the 'filepath' package? I cannot build leksah-server<br>
with GCC 7.4.2 because of this issue.<br>
<br>
Take care,<br>
Peter<br>
<br>
<br>
<br>
<br><br>---------- Forwarded message ----------<br>From: Hamish Mackenzie <<a href="mailto:hamish.k.mackenzie@gmail.com">hamish.k.mackenzie@gmail.com</a>><br>To: Peter Simons <<a href="mailto:simons@cryp.to">simons@cryp.to</a>><br>
Cc: <a href="mailto:gtk2hs-devel@lists.sourceforge.net">gtk2hs-devel@lists.sourceforge.net</a>, <a href="mailto:haskell-cafe@haskell.org">haskell-cafe@haskell.org</a><br>Date: Tue, 8 Jan 2013 14:05:08 +1300<br>Subject: Re: [Haskell-cafe] Announce: Leksah 0.13.1 (a bit experimental)<br>
Features in process-leksah have been merged into process. For<br>
newer versions of GHC leksah-server just depends on process.<br>
<br>
If it is trying to install process-leksah then something else<br>
has probably gone wrong.<br>
<br>
Check "ghc-pkg list" for old versions of leksah. Make sure<br>
you have the latest versions of ltk, leksah and leksah-server<br>
from github. (if you use cabal-meta they will be in<br>
the "leksah/vendor" subdirectory).<br>
<br>
Here are the steps for installing from scratch...<br>
<a href="https://github.com/leksah/leksah/blob/master/.travis.yml" target="_blank">https://github.com/leksah/leksah/blob/master/.travis.yml</a><br>
<br>
Here is what it should look like when it installs...<br>
<a href="https://travis-ci.org/leksah/leksah" target="_blank">https://travis-ci.org/leksah/leksah</a><br>
<br>
On 8 Jan 2013, at 07:25, Peter Simons <<a href="mailto:simons@cryp.to">simons@cryp.to</a>> wrote:<br>
<br>
> Hi Hamish,<br>
><br>
> would it be possible to get an update for process-leksah that works with<br>
> recent versions of the 'filepath' package? I cannot build leksah-server<br>
> with GCC 7.4.2 because of this issue.<br>
><br>
> Take care,<br>
> Peter<br>
><br>
><br>
> _______________________________________________<br>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br>Yuriy Solodkyy<br>(<a href="mailto:y.solodkyy@gmail.com">y.solodkyy@gmail.com</a>)
</div>