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.
-- Stefan^2.
Received on 2014-04-06 16:31:47 CEST