Subject: Re: [PATCH v4 0/4] Changed path filter hash fix and version bump

From: Derrick Stolee <[email-masked]>
Date: Fri, 23 Jun 2023 09:18:37 -0400

On 6/22/2023 6:27 PM, Jonathan Tan wrote:

> It looks like we can't avoid writing both versions (we need to write
> version 1 so that we can reuse existing Bloom filters when writing, if
> the repo has version 1 Bloom filters) so a config that tells us which to
> write sounds doable. I'll take a look.

I don't fully understand what you're saying here.

We need to be able to write both versions (not simultaneously, but
toggled via config) so we can roll out this change carefully instead
of suddenly due to the Git executable changing.

But we don't need to be able to write version 1 just so we can reuse
version 1 filters. In fact, we should be able to upgrade to version 2
if the config points at that, but we should _not_ re-use the filters
in that case.

This does present an interesting challenge for the upgrade: we have
the commitGraph.maxNewFilters option to limit the amount of new filters
we write at a given time. When shifting to version 2, we will start
from scratch, so that could have some effect. I will consider how to
handle this, perhaps by raising the number temporarily.

Thanks,
-Stolee