On 31 January 2014 05:50, Evgeny Kotkov <evgeny.kot...@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.
-- Ivan Zhakov CTO | VisualSVN | http://www.visualsvn.com
