Re: [PATCH] reachable: only mark local objects as recent

Jeff King [off-list ref] writes:

It is possible that we may drop an object that is depended
upon by another object in the alternate. For example,
imagine two repositories, A and B, with A pointing to B as
an alternate. Now imagine a commit that is in B which
references a tree that is only in A. Traversing from recent
objects in B might prevent A from dropping that tree. But
this case isn't worth covering. Repo B should take
responsibility for its own objects. It would never have had
the commit in the first place if it did not also have the
tree, and assuming it is using the same "keep recent chunks
of history" scheme, then it would itself keep the tree, as
well.

In other words, if you have a loop in dependency chain among
alternate repositories, your set-up is broken by definition.

Which makes sense to me.

Thanks.

On Fri, Mar 27, 2015 at 12:00:05PM -0700, Junio C Hamano wrote:

Jeff King [off-list ref] writes:

quoted

It is possible that we may drop an object that is depended
upon by another object in the alternate. For example,
imagine two repositories, A and B, with A pointing to B as
an alternate. Now imagine a commit that is in B which
references a tree that is only in A. Traversing from recent
objects in B might prevent A from dropping that tree. But
this case isn't worth covering. Repo B should take
responsibility for its own objects. It would never have had
the commit in the first place if it did not also have the
tree, and assuming it is using the same "keep recent chunks
of history" scheme, then it would itself keep the tree, as
well.

In other words, if you have a loop in dependency chain among
alternate repositories, your set-up is broken by definition.

Which makes sense to me.

Thanks.

I don't see this patch in "pu" or "What's Cooking" at all. Did it get
dropped?

It does fix a performance regression, but the problem is in v2.2, so I
don't think it's urgent for v2.4-rc.

-Peff