We're holding a Gerrit server cluster. And uses pull-replication plugin to sync changes between master and slave. When a change is pushed to master, it notify the slave, and slave fetch it from master. But we found in a big repository with 600k refs. Fetch takes 5-10 seconds even if fetching a 1 byte change. Here is the GIT_TRACE2_PERF I did an experiment to fetch a ref that my slave already have. And we can find git rev-list takes 2 seconds to perform. (I guess it try to find remote object from reachable objects of local refs one by one) Is there anyway to optimize such situation? 19:12:55.931180 common-main.c:48 | d0 | main | version | | | | | 2.33.1.558.g2bd2f258f4.dirty 19:12:55.931215 common-main.c:49 | d0 | main | start | | 0.000335 | | | git fetch --no-tags git://10.13.8.10/miui/gerrit/base-test.git refs/changes/27/2741927/1:refs/changes/27/2741927/1 19:12:55.931302 compat/linux/procinfo.c:170 | d0 | main | cmd_ancestry | | | | | ancestry:[bash sudo bash miauthd miauthd systemd] 19:12:55.931381 git.c:456 | d0 | main | cmd_name | | | | | fetch (fetch) 19:12:55.931566 builtin/fetch.c:1579 | d0 | main | region_enter | r0 | 0.000692 | | fetch | label:remote_refs 19:12:55.936781 connect.c:167 | d0 | main | data | | 0.005907 | 0.005215 | transfer | ..negotiated-version:2 19:12:55.940447 builtin/fetch.c:1582 | d0 | main | region_leave | r0 | 0.009573 | 0.008881 | fetch | label:remote_refs 19:12:56.221133 run-command.c:739 | d0 | main | child_start | | 0.290252 | | | [ch0] class:? argv:[git rev-list --objects --stdin --not --all --quiet --alternate-refs --unsorted-input] 19:12:58.014792 run-command.c:995 | d0 | main | child_exit | | 2.083899 | 1.793647 | | [ch0] pid:81860 code:0 19:12:58.014855 builtin/fetch.c:1321 | d0 | main | region_enter | r0 | 2.083980 | | fetch | label:consume_refs 19:12:58.015412 builtin/fetch.c:1326 | d0 | main | region_leave | r0 | 2.084538 | 0.000558 | fetch | label:consume_refs 19:12:58.015466 run-command.c:739 | d0 | main | child_start | | 2.084590 | | | [ch1] class:? argv:[git maintenance run --auto --no-quiet] 19:12:58.018879 common-main.c:48 | d1 | main | version | | | | | 2.33.1.558.g2bd2f258f4.dirty 19:12:58.018911 common-main.c:49 | d1 | main | start | | 0.000324 | | | /usr/libexec/git-core/git maintenance run --auto --no-quiet 19:12:58.019011 compat/linux/procinfo.c:170 | d1 | main | cmd_ancestry | | | | | ancestry:[git bash sudo bash miauthd miauthd systemd] 19:12:58.019087 git.c:456 | d1 | main | cmd_name | | | | | maintenance (fetch/maintenance) 19:12:58.019276 git.c:714 | d1 | main | exit | | 0.000690 | | | code:0 19:12:58.019284 trace2/tr2_tgt_perf.c:213 | d1 | main | atexit | | 0.000698 | | | code:0 19:12:58.019386 run-command.c:995 | d0 | main | child_exit | | 2.088507 | 0.003917 | | [ch1] pid:81878 code:0 19:12:58.019411 git.c:714 | d0 | main | exit | | 2.088538 | | | code:0 19:12:58.019419 trace2/tr2_tgt_perf.c:213 | d0 | main | atexit | | 2.088545 | | | code:0 #/******本邮件及其附件含有小米公司的保密信息，仅限于发送给上面地址中列出的个人或群组。禁止任何其他人以任何形式使用（包括但不限于全部或部分地泄露、复制、或散发）本邮件中的信息。如果您错收了本邮件，请您立即电话或邮件通知发件人并删除本邮件！ This e-mail and its attachments contain confidential information from XIAOMI, which is intended only for the person or entity whose address is listed above. Any use of the information contained herein in any way (including, but not limited to, total or partial disclosure, reproduction, or dissemination) by persons other than the intended recipient(s) is prohibited. If you receive this e-mail in error, please notify the sender by phone or email immediately and delete it!******/#
