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nodemap: also use persistent nodemap for manifest
authorPierre-Yves David <pierre-yves.david@octobus.net>
Sun, 05 Apr 2020 13:12:05 +0200
changeset 44786 640d5b3bd060
parent 44785 2c073d82fbfa
child 44787 97ebdb192b00
nodemap: also use persistent nodemap for manifest The manifest as a different usage pattern than the changelog. First, while the lookup in changelog are not garanteed to match, the lookup in the manifest nodemap come from changelog and will exist in the manifest. In addition, looking up a manifest almost always result in unpacking a manifest an operation that rarely come cheap. Nevertheless, using a persistent nodemap provide a significant gain for some operations. For our measurementw, we use `hg cat --rev REV FILE` on the our reference mozilla-try. On this repository the persistent nodemap cache is about 29 MB in side for a total store side of 11,988 MB File with large history (file: b2g/config/gaia.json, revision: 195a1146daa0) no optimisation: 0.358s using mmap for index: 0.297s (-0.061s) persistent nodemap for changelog only: 0.275s (-0.024s) persistent nodemap for manifest too: 0.258s (-0.017s) File with small history (file: .hgignore, revision: 195a1146daa0) no optimisation: 0.377s using mmap for index: 0.296s (-0.061s) persistent nodemap for changelog only: 0.274s (-0.022s) persistent nodemap for manifest too: 0.257s (-0.017s) Same file but using a revision (8ba995b74e18) with a smaller manifest (3944829 bytes vs 10 bytes) no optimisation: 0.192s (-0.185s) using mmap for index: 0.131s (-0.061s) persistent nodemap for changelog only: 0.106s (-0.025s) persistent nodemap for manifest too: 0.087s (-0.019s) Differential Revision: https://phab.mercurial-scm.org/D8410
mercurial/manifest.py file | annotate | diff | comparison | revisions
tests/test-persistent-nodemap.t file | annotate | diff | comparison | revisions 
--- a/mercurial/manifest.py	Sun Apr 05 13:49:27 2020 +0200
+++ b/mercurial/manifest.py	Sun Apr 05 13:12:05 2020 +0200
@@ -1588,6 +1588,9 @@
             checkambig=not bool(tree),
             mmaplargeindex=True,
             upperboundcomp=MAXCOMPRESSION,
+            persistentnodemap=opener.options.get(
+                b'exp-persistent-nodemap', False
+            ),
         )
 
         self.index = self._revlog.index
--- a/tests/test-persistent-nodemap.t	Sun Apr 05 13:49:27 2020 +0200
+++ b/tests/test-persistent-nodemap.t	Sun Apr 05 13:12:05 2020 +0200
@@ -32,6 +32,9 @@
 
   $ f --sha256 .hg/store/00changelog-*.nd
   .hg/store/00changelog-????????????????.nd: sha256=2e029d3200bd1a986b32784fc2ef1a3bd60dc331f025718bcf5ff44d93f026fd (glob)
+
+  $ f --sha256 .hg/store/00manifest-*.nd
+  .hg/store/00manifest-????????????????.nd: sha256=97117b1c064ea2f86664a124589e47db0e254e8d34739b5c5cc5bf31c9da2b51 (glob)
   $ hg debugnodemap --dump-new | f --sha256 --size
   size=121088, sha256=2e029d3200bd1a986b32784fc2ef1a3bd60dc331f025718bcf5ff44d93f026fd
   $ hg debugnodemap --dump-disk | f --sha256 --bytes=256 --hexdump --size
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