Comment 10 for bug 273859

I found another option which works correctly now:

I did set 'SVNAllowBulkUpdates Off' in my mod_dav_svn config file and now memory consumption stays normal (<450MB with about 10 users) during the whole checkout, even with about 1.6GB data / 6000 files to get (few hours required).
Before (default value is On when option is not explicitly set), I could easily get 500MB used after 15mn, if I let the process it would eventually fill up the whole RAM/swap.

To summarize, this option will force SVN clients to request only parts of the tree to get, and not the entire tree within one request.
Default behavior is to let the client decide which amount of data to get for one request.
This could explain why TortoiseSVN 1.6 has different behavior than SVN 1.6 command line version.
I indeed only got this memory problem using TortoiseSVN and not with SVN command line.

report to subversion team as http://subversion.tigris.org/issues/show_bug.cgi?id=3084