# HG changeset patch
# User Pierre-Yves David <pierre-yves.david@octobus.net>
# Date 1493899350 -7200
# Node ID d72c8c1f09e24ebb12692b45d9a048ce9e909e53
# Parent  3bb8382fc4cbaf9a913e88a8047b2435a8cdab51
obscache: document a possible way forward to skipping obsstore parsing

We document a possibly viable idea for updating the cache on new revs without
having to fully parse the obsstore.

diff --git a/hgext3rd/evolve/obscache.py b/hgext3rd/evolve/obscache.py
--- a/hgext3rd/evolve/obscache.py
+++ b/hgext3rd/evolve/obscache.py
@@ -305,6 +305,13 @@
         imagine using various optimisation (eg: another cache, network
         exchange, etc).
 
+        A possible approach to this is to build a set of all node used as
+        precursors in `obsstore._obscandidate`. If markers are not loaded yet,
+        we could initialize it by doing a quick scan through the obsstore data
+        and filling a (pre-sized) set. Doing so would be much faster than
+        parsing all the obsmarkers since we would access less data, not create
+        any object beside the nodes and not have to decode any complex data.
+
         For now we stick to the simpler approach of paying the
         performance cost on new changesets.
         """