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authorVincent Ambo <Vincent Ambo>2020-01-11T23·36+0000
committerVincent Ambo <Vincent Ambo>2020-01-11T23·36+0000
commit1b593e1ea4d2af0f6444d9a7788d5d99abd6fde5 (patch)
treee3accb9beed5c4c1b5a05c99db71ab2841f0ed04 /t/perf/p5551-fetch-rescan.sh
Squashed 'third_party/git/' content from commit cb71568594
git-subtree-dir: third_party/git
git-subtree-split: cb715685942260375e1eb8153b0768a376e4ece7
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diff --git a/t/perf/p5551-fetch-rescan.sh b/t/perf/p5551-fetch-rescan.sh
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+#!/bin/sh
+
+test_description='fetch performance with many packs
+
+It is common for fetch to consider objects that we might not have, and it is an
+easy mistake for the code to use a function like `parse_object` that might
+give the correct _answer_ on such an object, but do so slowly (due to
+re-scanning the pack directory for lookup failures).
+
+The resulting performance drop can be hard to notice in a real repository, but
+becomes quite large in a repository with a large number of packs. So this
+test creates a more pathological case, since any mistakes would produce a more
+noticeable slowdown.
+'
+. ./perf-lib.sh
+. "$TEST_DIRECTORY"/perf/lib-pack.sh
+
+test_expect_success 'create parent and child' '
+	git init parent &&
+	git clone parent child
+'
+
+
+test_expect_success 'create refs in the parent' '
+	(
+		cd parent &&
+		git commit --allow-empty -m foo &&
+		head=$(git rev-parse HEAD) &&
+		test_seq 1000 |
+		sed "s,.*,update refs/heads/& $head," |
+		$MODERN_GIT update-ref --stdin
+	)
+'
+
+test_expect_success 'create many packs in the child' '
+	(
+		cd child &&
+		setup_many_packs
+	)
+'
+
+test_perf 'fetch' '
+	# start at the same state for each iteration
+	obj=$($MODERN_GIT -C parent rev-parse HEAD) &&
+	(
+		cd child &&
+		$MODERN_GIT for-each-ref --format="delete %(refname)" refs/remotes |
+		$MODERN_GIT update-ref --stdin &&
+		rm -vf .git/objects/$(echo $obj | sed "s|^..|&/|") &&
+
+		git fetch
+	)
+'
+
+test_done