Merge branch 'mk/fix-batcher-if-more-source-records-than-destination-records' into 'master'

Geo: Fix registry backfilling

See merge request !87720

ee/lib/gitlab/geo/base_batcher.rb

@@ -47,12 +47,11 @@ def get_batch_last_id(batch_first_id)
         source_class_last_id, more_records = get_source_batch_last_id(batch_first_id)
         destination_class_last_id, more_destination_records = get_destination_batch_last_id(batch_first_id)
 
-        batch_last_id =
-          if !more_records && more_destination_records
-            destination_class_last_id
-          else
-            source_class_last_id
-          end
+        batch_last_id = if source_class_last_id && destination_class_last_id
+                          [source_class_last_id, destination_class_last_id].max
+                        else
+                          source_class_last_id || destination_class_last_id
+                        end
 
         if more_records || more_destination_records
           increment_batch(batch_last_id)
@@ -116,7 +115,7 @@ def get_destination_batch_last_id(batch_first_id)
           EXISTS (
             SELECT #{source_foreign_key}
             FROM #{destination_class.table_name}
-            WHERE #{source_foreign_key} >= MAX(batch.#{source_foreign_key})
+            WHERE #{source_foreign_key} > MAX(batch.#{source_foreign_key})
           ) AS more_rows
           FROM (
             SELECT #{source_foreign_key}

ee/spec/support/shared_examples/models/geo_batcher_shared_examples.rb

@@ -44,7 +44,9 @@
             described_class.new(destination_class, key: key, batch_size: destination_class.count).next_range!
           end
 
-          it { is_expected.to be_nil }
+          it 'starts from the beginning' do
+            expect(subject).to eq(1..destination_records.second.public_send(source_foreign_key))
+          end
         end
 
         context 'when the previous batch did not include the end of the table' do
@@ -155,7 +157,9 @@
           described_class.new(destination_class, key: key, batch_size: batch_size).next_range!
         end
 
-        it { is_expected.to be_nil }
+        it 'starts from the beginning' do
+          expect(subject).to eq(1..orphaned_destination_foreign_key_id)
+        end
 
         context 'if cache is cleared' do
           it 'starts from the beginning' do