bdr: document types of conflicts and their resolution (internals)

diff --git a/contrib/bdr/conflicts.txt b/contrib/bdr/conflicts.txt
new file mode 100644 (file)
index 0000000..c57df4d
--- /dev/null
+++ b/contrib/bdr/conflicts.txt
@@ -0,0 +1,15 @@
+type of conflict: UPDATE vs UPDATE
+detection: compare timestamp
+resolution: only apply later UPDATE
+
+type of conflict: INSERT vs INSERT
+detection: uniqueness violation
+resolution: convert INSERT into UPDATE, use UPDATE resolution
+
+type of conflict: UPDATE vs DELETE
+detection: primary key doesn't exist
+resolution: skip update, it's going to (or has been) deleted anyway
+
+type of conflict: DELETE vs DELETE
+detection: primary key doesn't exist
+resolution: skip