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path: root/t/perf/p5551-fetch-rescan.sh
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2017-11-21p5551: add a script to test fetch pack-dir rescansLibravatar Jeff King1-0/+55
Since fetch often deals with object-ids we don't have (yet), it's an easy mistake for it to use a function like parse_object() that gives the correct result (e.g., NULL) but does so very slowly (because after failing to find the object, we re-scan the pack directory looking for new packs). The regular test suite won't catch this because the end result is correct, but we would want to know about performance regressions, too. Let's add a test to the regression suite. Note that this uses a synthetic repository that has a large number of packs. That's not ideal, as it means we're not testing what "normal" users see (in fact, some of these problems have existed for ages without anybody noticing simply because a rescan on a normal repository just isn't that expensive). So what we're really looking for here is the spike you'd notice in a pathological case (a lot of unknown objects coming into a repo with a lot of packs). If that's fast, then the normal cases should be, too. Note that the test also makes liberal use of $MODERN_GIT for setup; some of these regressions go back a ways, and we should be able to use it to find the problems there. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>