diff mercurial/debugcommands.py @ 33057:03eefca3ed33

debugrevlog: also display the largest delta chain span

Mercurial read all data between the base of the chain and the last delta when
restoring content (including unrelated delta). To monitor this, we add data
about the size of the "delta chain span" to debugrevlog.

--- a/mercurial/debugcommands.py	Sat Jun 24 21:13:48 2017 -0700
+++ b/mercurial/debugcommands.py	Fri Jun 23 01:38:10 2017 +0200
@@ -1749,6 +1749,8 @@
     nump1prev = 0
     nump2prev = 0
     chainlengths = []
+    chainbases = []
+    chainspans = []
 
     datasize = [None, 0, 0]
     fullsize = [None, 0, 0]
@@ -1774,10 +1776,16 @@
         size = r.length(rev)
         if delta == nullrev:
             chainlengths.append(0)
+            chainbases.append(r.start(rev))
+            chainspans.append(size)
             numfull += 1
             addsize(size, fullsize)
         else:
             chainlengths.append(chainlengths[delta] + 1)
+            baseaddr = chainbases[delta]
+            revaddr = r.start(rev)
+            chainbases.append(baseaddr)
+            chainspans.append((revaddr - baseaddr) + size)
             addsize(size, deltasize)
             if delta == rev - 1:
                 numprev += 1
@@ -1823,6 +1831,7 @@
     totalsize = fulltotal + deltatotal
     avgchainlen = sum(chainlengths) / numrevs
     maxchainlen = max(chainlengths)
+    maxchainspan = max(chainspans)
     compratio = 1
     if totalsize:
         compratio = totalrawsize / totalsize
@@ -1879,6 +1888,7 @@
     fmt = dfmtstr(max(avgchainlen, compratio))
     ui.write(('avg chain length  : ') + fmt % avgchainlen)
     ui.write(('max chain length  : ') + fmt % maxchainlen)
+    ui.write(('max chain reach  : ') + fmt % maxchainspan)
     ui.write(('compression ratio : ') + fmt % compratio)
 
     if format > 0: