From: Junio C Hamano Date: Tue, 17 May 2022 10:27:04 GMT Subject: Re: [PATCH v2] fetch: limit shared symref check only for local branches Message-ID: In-Reply-To: Orgad Shaneh writes: >> Another thing that is surprising is that you say this loop is >> expensive when there are many tags or branches. Do you mean it is >> expensive when there are many tags and branches that are updated, or >> it is expensive to merely have thousands of dormant tags and >> branches? If the latter, I wonder if it is sensible to limit the >> check only to the refs that are going to be updated. > > It's expensive even when *nothing* is updated. I have a repo with 44K > tags, 13K of the tags are annotated, 134 remote branches and 4 > worktrees (except the main repo) with 33 local branches. > > I counted the calls to find_shared_symref - it was called 35755 times, > and refs_read_raw_ref was called 357585 times. That is exactly why I asked, as the above number hints that it could be a viable optimization to omit calls for refs whose old_ and new_oid are the same, just like you omit calls for refs that are not inside refs/heads/ in your patch, perhaps?