TODO: Add a couple of notes about things to do with/to Xapian.

[notmuch] / TODO

diff --git a/TODO b/TODO
index 8783ebb61be9a6f42a7407a5690e6c8edaff683c..b85d33102f17e5d0fe536696acd62e325181121a 100644 (file)
--- a/TODO
+++ b/TODO
@@ -134,3 +134,50 @@ Achieve 100% test coverage with the test suite.
 
 Investigate why the notmuch database is slightly larger than the sup
 database for the same corpus of email.
+
+Xapian
+------
+Fix defect #250
+
+       replace_document should make minimal changes to database file
+       http://trac.xapian.org/ticket/250
+
+       It looks like it's going to be easy to fix. Here's the file to
+       change:
+
+               xapian-core/backends/flint/flint_database.cc
+
+       And look for:
+
+         // FIXME - in the case where there is overlap between the new
+         // termlist and the old termlist, it would be better to compare the
+         // two lists, and make the minimum set of modifications required.
+         // This would lead to smaller changesets for replication, and
+         // probably be faster overall
+
+       So I think this might be as easy as just walking over two
+       sorted lists looking for differences.
+
+       Note that this is in the currently default "flint" backend,
+       but the Xapian folks are probably more interested in fixing
+       the in-development "chert" backend. So the patch to get
+       upstreamed there will probably also fix:
+
+               xapian-core/backends/chert/chert_database.cc
+
+       (I'm hoping the fix will be the same---an identical comment
+       exists there.)
+
+       Also, if you want to experiment with the chert backend,
+       compile current Xapian source and run notmuch with
+       XAPIAN_PREFER_CHERT=1. I haven't tried that yet, but there are
+       claims that a chert database can be 40% smaller than an
+       equivalent flint database.
+
+Report this bug:
+
+       "tag:foo and tag:bar and -tag:deleted" goes insane
+
+       This seems to be triggered by a Boolean operator next to a
+       token starting with a non-word character---suddenly all the
+       Boolean operators get treated as literal tokens)