[[!img notmuch-logo.png alt="Notmuch logo" class="left"]]
-# Troubleshooting and Bug reporting
+# Troubleshooting and Bug Reporting
+
+[[!toc levels=2]]
## Deciding what level the problem lives at
involved with this tagging process, but feel free to just send mail to
the list; someone will tag messages appropriately. The status of bugs
and current patches can also be followed
-[online](http://nmbug.notmuchmail.org/status).
+[online](https://nmbug.notmuchmail.org/status).
+
+## Debugging Queries
+
+If a search doesn't seem to do what you want, you can enable query debugging to
+print the Xapian queries the Notmuch library constructs by setting the
+`NOTMUCH_DEBUG_QUERY` environment variable to a non-empty value.
+
+For example:
+
+ $ NOTMUCH_DEBUG_QUERY=1 notmuch search big brown fox
+ Query string is:
+ big brown fox
+ Exclude query is:
+ Xapian::Query()
+ Final query is:
+ Xapian::Query((Tmail AND Zbig:(pos=1) AND Zbrown:(pos=2) AND Zfox:(pos=3)))
+## Rescuing your tags.
+If you're database is corrupt and you don't have a backup, a modified version of [xapian-check](https://git.xapian.org/?p=xapian;a=blob;f=README.notmuch;hb=refs/heads/notmuch-tag-rescue-hack) might still save your tags.