branchmap: update rev-branch-cache incrementally

Historically, the revision to branch mapping cache was updated on demand
and shared via bundle2 to avoid the cost of rebuilding on first use.

Use the new `register_changeset` callback and update rbc directly on
every change. Make the transfer of the bundle part redundant, but keep
it for the moment to avoid the test churn.

Over all, "hg unbundle" for large bundles is less than 1.8% slower for
different larger repositories and that seems to a reasonable trade off.

Differential Revision: https://phab.mercurial-scm.org/D9781

mercurial/branchmap.py

@@ -706,8 +706,10 b' class revbranchcache(object):'
         self._setcachedata(rev, reponode, branchidx)
         return b, close
 
-    def setdata(self, branch, rev, node, close):
+    def setdata(self, rev, changelogrevision):
         """add new data information to the cache"""
+        branch, close = changelogrevision.branchinfo
+
         if branch in self._namesreverse:
             branchidx = self._namesreverse[branch]
         else:
@@ -716,7 +718,7 b' class revbranchcache(object):'
             self._namesreverse[branch] = branchidx
         if close:
             branchidx |= _rbccloseflag
-        self._setcachedata(rev, node, branchidx)
+        self._setcachedata(rev, self._repo.changelog.node(rev), branchidx)
         # If no cache data were readable (non exists, bad permission, etc)
         # the cache was bypassing itself by setting:
         #

mercurial/bundle2.py

@@ -2478,35 +2478,10 b" rbcstruct = struct.Struct(b'>III')"
 
 @parthandler(b'cache:rev-branch-cache')
 def handlerbc(op, inpart):
-    """receive a rev-branch-cache payload and update the local cache
-
-    The payload is a series of data related to each branch
-
-    1) branch name length
-    2) number of open heads
-    3) number of closed heads
-    4) open heads nodes
-    5) closed heads nodes
-    """
-    total = 0
-    rawheader = inpart.read(rbcstruct.size)
-    cache = op.repo.revbranchcache()
-    cl = op.repo.unfiltered().changelog
-    while rawheader:
-        header = rbcstruct.unpack(rawheader)
-        total += header[1] + header[2]
-        utf8branch = inpart.read(header[0])
-        branch = encoding.tolocal(utf8branch)
-        for x in pycompat.xrange(header[1]):
-            node = inpart.read(20)
-            rev = cl.rev(node)
-            cache.setdata(branch, rev, node, False)
-        for x in pycompat.xrange(header[2]):
-            node = inpart.read(20)
-            rev = cl.rev(node)
-            cache.setdata(branch, rev, node, True)
-        rawheader = inpart.read(rbcstruct.size)
-    cache.write()
+    """Legacy part, ignored for compatibility with bundles from or
+    for Mercurial before 5.7. Newer Mercurial computes the cache
+    efficiently enough during unbundling that the additional transfer
+    is unnecessary."""
 
 
 @parthandler(b'pushvars')

mercurial/localrepo.py

@@ -2063,7 +2063,7 b' class localrepository(object):'
         return self._revbranchcache
 
     def register_changeset(self, rev, changelogrevision):
-        pass
+        self.revbranchcache().setdata(rev, changelogrevision)
 
     def branchtip(self, branch, ignoremissing=False):
         """return the tip node for a given branch

relnotes/next

@@ -44,6 +44,9 b''
  * The `branchmap` cache is updated more intelligently and can be
    significantly faster for repositories with many branches and changesets.
 
+ * The `rev-branch-cache` is now updated incrementally whenever changesets
+   are added.
+
 
 == New Experimental Features ==
 

tests/test-acl.t

@@ -204,6 +204,7 b' Extension disabled for lack of acl.sourc'
   bundle2-input-part: "phase-heads" supported
   bundle2-input-part: total payload size 24
   bundle2-input-bundle: 5 parts total
+  truncating cache/rbc-revs-v1 to 8
   updating the branch cache
   added 3 changesets with 3 changes to 3 files
   bundle2-output-bundle: "HG20", 1 parts total
@@ -283,6 +284,7 b' No [acl.allow]/[acl.deny]'
   bundle2-input-part: "phase-heads" supported
   bundle2-input-part: total payload size 24
   bundle2-input-bundle: 5 parts total
+  truncating cache/rbc-revs-v1 to 8
   updating the branch cache
   added 3 changesets with 3 changes to 3 files
   bundle2-output-bundle: "HG20", 1 parts total
@@ -806,6 +808,7 b' fred is not blocked from moving bookmark'
   acl: acl.deny.bookmarks not enabled
   acl: bookmark access granted: "ef1ea85a6374b77d6da9dcda9541f498f2d17df7" on bookmark "moving-bookmark"
   bundle2-input-bundle: 7 parts total
+  truncating cache/rbc-revs-v1 to 8
   updating the branch cache
   invalid branch cache (served.hidden): tip differs
   added 1 changesets with 1 changes to 1 files
@@ -982,6 +985,7 b' barney is allowed everywhere'
   bundle2-input-part: "phase-heads" supported
   bundle2-input-part: total payload size 24
   bundle2-input-bundle: 5 parts total
+  truncating cache/rbc-revs-v1 to 8
   updating the branch cache
   added 3 changesets with 3 changes to 3 files
   bundle2-output-bundle: "HG20", 1 parts total
@@ -1318,6 +1322,7 b' acl.config can set only [acl.allow]/[acl'
   bundle2-input-part: "phase-heads" supported
   bundle2-input-part: total payload size 24
   bundle2-input-bundle: 5 parts total
+  truncating cache/rbc-revs-v1 to 8
   updating the branch cache
   added 3 changesets with 3 changes to 3 files
   bundle2-output-bundle: "HG20", 1 parts total
@@ -1408,6 +1413,7 b' fred is always allowed'
   bundle2-input-part: "phase-heads" supported
   bundle2-input-part: total payload size 24
   bundle2-input-bundle: 5 parts total
+  truncating cache/rbc-revs-v1 to 8
   updating the branch cache
   added 3 changesets with 3 changes to 3 files
   bundle2-output-bundle: "HG20", 1 parts total
@@ -1577,6 +1583,7 b' OS-level groups'
   bundle2-input-part: "phase-heads" supported
   bundle2-input-part: total payload size 24
   bundle2-input-bundle: 5 parts total
+  truncating cache/rbc-revs-v1 to 8
   updating the branch cache
   added 3 changesets with 3 changes to 3 files
   bundle2-output-bundle: "HG20", 1 parts total

tests/test-inherit-mode.t

@@ -134,6 +134,8 b' group can still write everything'
   00660 ../push/.hg/00changelog.i
   00770 ../push/.hg/cache/
   00660 ../push/.hg/cache/branch2-base
+  00660 ../push/.hg/cache/rbc-names-v1
+  00660 ../push/.hg/cache/rbc-revs-v1
   00660 ../push/.hg/dirstate
   00660 ../push/.hg/requires
   00770 ../push/.hg/store/

tests/test-rebase-conflicts.t

@@ -318,10 +318,10 b' Check that the right ancestors is used w'
   bundle2-input-part: total payload size 1686
   bundle2-input-part: "cache:rev-branch-cache" (advisory) supported
   bundle2-input-part: total payload size 74
-  truncating cache/rbc-revs-v1 to 56
   bundle2-input-part: "phase-heads" supported
   bundle2-input-part: total payload size 24
   bundle2-input-bundle: 3 parts total
+  truncating cache/rbc-revs-v1 to 72
   added 2 changesets with 2 changes to 1 files
   updating the branch cache
   invalid branch cache (served): tip differs