commandserver: preload repository in master server and reuse its file cache This greatly speeds up repository operation with lots of obsolete markers: $ ls -lh .hg/store/obsstore -rw-r--r-- 1 yuya yuya 21M Dec 2 17:55 .hg/store/obsstore $ time hg log -G -l10 --pager no (hg) 1.79s user 0.13s system 99% cpu 1.919 total (chg uncached) 0.00s user 0.01s system 0% cpu 1.328 total (chg cached) 0.00s user 0.00s system 3% cpu 0.180 total As you can see, the implementation of the preloader function is highly experimental. It works, but I'm yet to be sure how things can be organized. So I don't want to formalize the API at this point.

--- a/mercurial/configitems.py	Wed Oct 31 22:19:03 2018 +0900
+++ b/mercurial/configitems.py	Wed Oct 31 22:43:08 2018 +0900
@@ -179,11 +179,14 @@
 coreconfigitem('cmdserver', 'max-log-size',
     default='1 MB',
 )
+coreconfigitem('cmdserver', 'max-repo-cache',
+    default=0,
+)
 coreconfigitem('cmdserver', 'message-encodings',
     default=list,
 )
 coreconfigitem('cmdserver', 'track-log',
-    default=lambda: ['chgserver', 'cmdserver'],
+    default=lambda: ['chgserver', 'cmdserver', 'repocache'],
 )
 coreconfigitem('color', '.*',
     default=None,