On Sun, Apr 6, 2014 at 5:36 PM, Ivan Zhakov <ivan_at_visualsvn.com> wrote:
> On 6 April 2014 18:31, Stefan Fuhrmann <stefan.fuhrmann_at_wandisco.com>
> wrote:
> > On Wed, Apr 2, 2014 at 12:13 PM, Ivan Zhakov <ivan_at_visualsvn.com> wrote:
> >>
> >> On 31 January 2014 14:57, Ivan Zhakov <ivan_at_visualsvn.com> wrote:
> >> > On 31 January 2014 05:50, Evgeny Kotkov <evgeny.kotkov_at_visualsvn.com>
> >> > wrote:
> >> >>> This only affects non-sharded repositories with rev-local IDs,
> >> >>> i.e. those in SVN 1.4 format. For those, it is writing 3 files
> >> >>> instead of 2 per rev now.
> >> >>
> >> >> I assume you are talking about r1560723 [1]. If I read the code
> >> >> correctly...
> >> >> [[[
> >> >> if ( (!max_files_per_dir || rev % max_files_per_dir == 0)
> >> >> && dst_ffd->format >= SVN_FS_FS__MIN_NO_GLOBAL_IDS_FORMAT)
> >> >> SVN_ERR(hotcopy_update_current(&dst_youngest, dst_fs, rev,
> >> >> iterpool));
> >> >> ]]]
> >> >>
> >> >> ...hotcopy now checkpoints after every revision for all non-sharded
> >> >> repositories
> >> >> with FSFS format >= 3. So, checkpointing happens for all FSFS format
> >> >> 1/2
> >> >> repositories upgraded via 'svnadmin upgrade' (with linear layout),
> that
> >> >> were
> >> >> not fsfs-reshard'ed or dump/loaded into a repository with newer
> format.
> >> >>
> >> >> I am not aware of how many people reshard or dump/load their old
> >> >> repositories
> >> >> after upgrade, but I did a quick benchmark for a real-world
> repository
> >> >> and on my
> >> >> machine it shows 7x performance degradation with checkpointing
> enabled.
> >> >> Is it
> >> >> worth the ability to re-run the backup from a checkpoint upon
> >> >> cancellation?
> >> >>
> >> >> [[[
> >> >> # svnrdump http://googletest.googlecode.com/svn/trunk/
> >> >> # load the dump into a --compatible-version=1.3 repository
> >> >> # upgrade the repository with the most recent svnadmin
> >> >>
> >> >> # disable checkpointing, benchmark making 100 hotcopy backups:
> >> >> real 0m18.741s
> >> >> user 0m2.552s
> >> >> sys 0m13.432s
> >> >>
> >> >> # now enable checkpointing and repeat the benchmark:
> >> >> real 2m5.793s
> >> >> user 0m0.836s
> >> >> sys 0m34.840s
> >> >> ]]]
> >> >>
> >> >> [1] http://svn.apache.org/viewvc?view=revision&revision=r1560723
> >> >>
> >> > That's what I suspected. In this case I think r1560723 should not be
> >> > backported to 1.8.x for the following reasons:
> >> > 1. Significant performance degradation for 'svnadmin hotcopy' with
> >> > '--incremental' flag.
> >> > 2. The change doesn't fix original circular dependency problem in FSFS
> >> > 3. 'svnadmin recover' writes fake value to CURRENT file which very bad
> >> > practice IMHO and could lead undefined consequences.
> >> >
> >> Hi Stefan,
> >>
> >> Is this problem fixed or it's better to revert r1560723 for reasons I
> >> stated above?
> >
> >
> > Hi Ivan,
> >
> > Evgeny applied his patch a month ago as r1573744.
> >
> Hi Stefan,
>
> Yes, I know. But svnadmin hotcopy performance regression was not fixed
> as far I know.
>
Oh - sorry!
When I read your post, I didn't expand the quote.
I don't have string feelings either way. As it makes
laggards happy, I'm fine with the revert.
Reverted in r1585516.
-- Stefan^2.
Received on 2014-04-07 18:38:37 CEST