Hi,
On Apr 3, 2012, at 12:50 PM, Jukka Zitting wrote:
> Hi,
>
> On Tue, Apr 3, 2012 at 11:56 AM, Dominique Pfister <dpfis...@adobe.com> wrote:
>> On Apr 3, 2012, at 11:51 AM, Jukka Zitting wrote:
>>> You'd drop revision identifiers from the MicroKernel interface? That's
>>> a pretty big design change...
>>
>> No, I probably did not make myself clear: I would not keep a revision
>> (and all its nodes) reachable in terms of garbage collection, simply
>> because it was accessed by a client some time ago.
>
> If that's the case, I'm worried about what could happen to code like this:
>
> String revision = mk.getHeadRevision();
> String root = getNodes("/", revision);
>
> Suppose someone else makes a commit in between the two calls and the
> garbage collector gets triggered. The result then would be that the
> getNodes() call will fail because the given revision identifier is no
> longer available.
If we have a delay of 10 minutes for revisions getting garbage collected, this
would imply that 10 minutes passed between the first call and the second call,
right? This seems rather unlikely.
>
> And if you consider that an unlikely enough scenario, consider a case
> where I want to then page through a potentially large list of the
> child nodes:
>
> int page_size = 10;
> long count = getChildNodeCount(root);
> for (long offset = 0; offset < count; offset += page_size) {
> String children = mk.getNodes("/", revision, 1, offset,
> page_size, null);
> }
>
> That could take a potentially long time, during which the revision
> might well get garbage-collected. How should a client prepare for such
> a situation?
If simply iterating over this large list takes longer than the 10 minutes
mentioned above, you'd have REALLY have a lot of child nodes. And if the client
does some work in between (or waits for some other user interaction to continue
paging), I guess it must be able to handle this situation gracefully.
I'm just worried about the other extreme: if you have a lot of such clients
requesting large child node lists on different head revisions, the garbage
collector will never be able to actually collect a revision and space will run
out soon.
Dominique
>
> BR,
>
> Jukka Zitting
