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Re: Disabling ffd->svn_cache__t Re: svn commit: r1462413 - in /subversion/trunk/subversion: include/svn_fs.h libsvn_fs_fs/fs_fs.c

From: Stefan Fuhrmann <stefan.fuhrmann_at_wandisco.com>
Date: Fri, 29 Mar 2013 11:45:23 +0100

On Fri, Mar 29, 2013 at 7:19 AM, Daniel Shahaf <danielsh_at_elego.de> wrote:

> I have a function that looks like this:
>
> static svn_error_t *f(svn_fs_t *fs)
> {
> svn_fs_t *ft = svn_fs_open(fs);
> svn_fs_verify_root(ft, r42);
> }
>
> I'd like the 'verify' call to bypass any information that is already
> cached: I don't mind if it the 'verify' process caches information for
> itself and then reads it back, but I don't want it to read information
> that is _right now_ in the cache (due to FS, or some other handle to the
> same filesystem in another thread) in lieu of parsing it, for itself,
> from the revision file.
>
> What would be the best way to achieve this? Do I set every cache in
> ft->ffd->* to NULL or to a pointer to a newly-created, empty cache object?
> Something else?
>

Originally, I had planned to introduce cache namespaces in 1.9
because all processes would share the same cache memory
(so, svnadmin would then need use a separate key space).

But since you obviously needed right now, I added the feature
now in 1462436 on /trunk. Since I changed your code from
r1462413, please have a look at my commit to ensure that it
still does what you intended.

-- Stefan^2.

danielsh_at_apache.org wrote on Fri, Mar 29, 2013 at 06:08:55 -0000:
> > Author: danielsh
> > Date: Fri Mar 29 06:08:55 2013
> > New Revision: 1462413
> >
> > URL: http://svn.apache.org/r1462413
> > Log:
> > In the FSFS "paranoid verify" code, disable caching. See within for a
> question.
> >
> > * subversion/include/svn_fs.h
> > (SVN_FS_CONFIG_FSFS_CACHE_*): Add a note to maintainers who add such
> symbols.
> >
> > * subversion/libsvn_fs_fs/fs_fs.c
> > (verify_as_revision_before_current_plus_plus):
> > Disable caches the API allows to disable, and add a question.
> >
> > Modified:
> > subversion/trunk/subversion/include/svn_fs.h
> > subversion/trunk/subversion/libsvn_fs_fs/fs_fs.c
> >
> > Modified: subversion/trunk/subversion/libsvn_fs_fs/fs_fs.c
> > URL:
> http://svn.apache.org/viewvc/subversion/trunk/subversion/libsvn_fs_fs/fs_fs.c?rev=1462413&r1=1462412&r2=1462413&view=diff
> >
> ==============================================================================
> > --- subversion/trunk/subversion/libsvn_fs_fs/fs_fs.c (original)
> > +++ subversion/trunk/subversion/libsvn_fs_fs/fs_fs.c Fri Mar 29 06:08:55
> 2013
> > @@ -8278,11 +8278,20 @@ verify_as_revision_before_current_plus_p
> > svn_fs_t *ft; /* fs++ == ft */
> > svn_fs_root_t *root;
> > fs_fs_data_t *ft_ffd;
> > + apr_hash_t *fs_config;
> >
> > SVN_ERR_ASSERT(ffd->svn_fs_open_);
> >
> > + fs_config = apr_hash_make(pool);
> > + svn_hash_sets(fs_config, SVN_FS_CONFIG_FSFS_CACHE_DELTAS, "0");
> > + svn_hash_sets(fs_config, SVN_FS_CONFIG_FSFS_CACHE_FULLTEXTS, "0");
> > + svn_hash_sets(fs_config, SVN_FS_CONFIG_FSFS_CACHE_REVPROPS, "0");
> > + /* ### TODO: are there any other intra-process caches that FS
> populated
> > + and FT will read from? Can we disable those (for FT at
> least)?
> > + */
> > +
> > SVN_ERR(ffd->svn_fs_open_(&ft, fs->path,
> > - NULL /* ### TODO fs_config */,
> > + fs_config,
> > pool));
> > ft_ffd = ft->fsap_data;
> >
> >
> >
>

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Received on 2013-03-29 11:46:00 CET

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