1 files changed, 3 insertions, 0 deletions
diff --git a/lib/PublicInbox/Search.pm b/lib/PublicInbox/Search.pm
index 1874ee9d..b6e71da0 100644
--- a/lib/PublicInbox/Search.pm
+++ b/lib/PublicInbox/Search.pm
@@ -28,6 +28,9 @@ use constant {
          # 8 - remove redundant/unneeded document data
          # 9 - disable Message-ID compression
          SCHEMA_VERSION => 9,
+
+        # n.b. FLAG_PURE_NOT is expensive not suitable for a public website
+        # as it could become a denial-of-service vector
          QP_FLAGS => FLAG_PHRASE|FLAG_BOOLEAN|FLAG_LOVEHATE|FLAG_WILDCARD,
  };