[GHC] #15938: Hadrian's recompilation check is extremely slow

[GHC]

#15938: Hadrian's recompilation check is extremely slow
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        Reporter:  bgamari           |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.8.1
       Component:  Build System      |              Version:  8.6.2
  (Hadrian)                          |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by snowleopard):

 Aha, I see. One theory I have is that the cache oracles we added for
 various Cabal parsing actions [1] have not been recorded in the database
 on `Ctrl-C`, hence we need to rerun them. Perhaps, Shake saves these
 cached oracles only on successful completion of a build?

 [1] https://github.com/snowleopard/hadrian/pull/692

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15938#comment:6>
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