[PATCH 2/2] docs/rev-list: add some examples of --disk-usage

From: Jeff King <peff@peff.net>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: Taylor Blau <me@ttaylorr.com>, Junio C Hamano <gitster@pobox.com>,
	git@vger.kernel.org, Kyle Meyer <kyle@kyleam.com>,
	Eric Sunshine <sunshine@sunshineco.com>
Subject: [PATCH 2/2] docs/rev-list: add some examples of --disk-usage
Date: Wed, 17 Feb 2021 18:35:33 -0500	[thread overview]
Message-ID: <YC2oRaMtBo/zMBmi@coredump.intra.peff.net> (raw)
In-Reply-To: <YC2nOxPP3SAY2g1I@coredump.intra.peff.net>

It's not immediately obvious why --disk-usage might be a useful thing.
These examples show off a few of the real-world cases I've used it for.

Signed-off-by: Jeff King <peff@peff.net>
---
 Documentation/git-rev-list.txt | 41 ++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/Documentation/git-rev-list.txt b/Documentation/git-rev-list.txt
index d7ff519b90..20bb8e8217 100644
--- a/Documentation/git-rev-list.txt
+++ b/Documentation/git-rev-list.txt
@@ -83,6 +83,47 @@ git rev-list --author=you@example.com --since=1.year.ago --all
 git rev-list --objects HEAD
 ----------
 
+* Compare the disk size of all reachable objects, versus those
+  reachable from reflogs, versus the total packed size. This can tell
+  you whether running `git repack -ad` might reduce the repository size
+  (by dropping unreachable objects), and whether expiring reflogs might
+  help.
++
+----------
+# reachable objects
+git rev-list --disk-usage --objects --all
+# plus reflogs
+git rev-list --disk-usage --objects --all --reflog
+# total disk size used
+du -c .git/objects/pack/*.pack .git/objects/??/*
+# alternative to du: add up "size" and "size-pack" fields
+git count-objects -v
+----------
+
+* Report the disk size of each branch, not including objects used by the
+  current branch. This can find outliers that are contributing to a
+  bloated repository size (e.g., because somebody accidentally committed
+  large build artifacts).
++
+----------
+git for-each-ref --format='%(refname)' |
+while read branch
+do
+	size=$(git rev-list --disk-usage --objects HEAD..$branch)
+	echo "$size $branch"
+done |
+sort -n
+----------
+
+* Compare the on-disk size of branches in one group of refs, excluding
+  another. If you co-mingle objects from multiple remotes in a single
+  repository, this can show which remotes are contributing to the
+  repository size (taking the size of `origin` as a baseline).
++
+----------
+git rev-list --disk-usage --objects --remotes=$suspect --not --remotes=origin
+----------
+
 GIT
 ---
 Part of the linkgit:git[1] suite
-- 
2.30.1.989.g5e01c2f281
