SERVER-63819 Make range deletion's `numOrphanDocs` field non-optional once 6.0 branches out

8 files changed, 10 insertions, 19 deletions

diff --git a/jstests/sharding/resubmit_rangedeletions_on_stepup.js b/jstests/sharding/resubmit_rangedeletions_on_stepup.js
index 3cded7ef852..0a8c92ff10e 100644
--- a/jstests/sharding/resubmit_rangedeletions_on_stepup.js
+++ b/jstests/sharding/resubmit_rangedeletions_on_stepup.js
@@ -29,12 +29,13 @@ function setup() {
     return st;
 }
 
-function writeRangeDeletionTask(collectionUuid, shardConn, pending) {
+function writeRangeDeletionTask(collectionUuid, shardConn, pending, numOrphans) {
     let deletionTask = {
         _id: UUID(),
         nss: ns,
         collectionUuid: collectionUuid,
         donorShardId: "unused",
+        numOrphanDocs: numOrphans,
         range: {min: {x: 50}, max: {x: MaxKey}},
         whenToClean: "now"
     };
@@ -84,7 +85,7 @@ function writeRangeDeletionTask(collectionUuid, shardConn, pending) {
     assert.eq(shard1Coll.find().itcount(), expectedNumDocsShard1);
 
     const collectionUuid = getUUIDFromConfigCollections(st.s, ns);
-    writeRangeDeletionTask(collectionUuid, st.shard0);
+    writeRangeDeletionTask(collectionUuid, st.shard0, false, orphanCount);
 
     // Step down current primary.
     let originalShard0Primary = st.rs0.getPrimary();
@@ -123,7 +124,7 @@ function writeRangeDeletionTask(collectionUuid, shardConn, pending) {
     }
 
     const collectionUuid = getUUIDFromConfigCollections(st.s, ns);
-    writeRangeDeletionTask(collectionUuid, st.shard0, true);
+    writeRangeDeletionTask(collectionUuid, st.shard0, true, orphanCount);
 
     const expectedNumDocsTotal = 0;
     const expectedNumDocsShard0 = 0;
diff --git a/jstests/sharding/updates_to_rangedeletions_collection_trigger_range_deletions.js b/jstests/sharding/updates_to_rangedeletions_collection_trigger_range_deletions.js
index fe356704ed6..e96c7dfe168 100644
--- a/jstests/sharding/updates_to_rangedeletions_collection_trigger_range_deletions.js
+++ b/jstests/sharding/updates_to_rangedeletions_collection_trigger_range_deletions.js
@@ -127,6 +127,7 @@ let testColl = testDB.foo;
         collectionUuid: UUID(),
         donorShardId: "unused",
         pending: true,
+        numOrphanDocs: 0,
         range: {min: {x: 70}, max: {x: 90}},
         whenToClean: "now"
     };
diff --git a/src/mongo/db/s/migration_coordinator.cpp b/src/mongo/db/s/migration_coordinator.cpp
index 46c8a0d611a..8a6b1f4da2f 100644
--- a/src/mongo/db/s/migration_coordinator.cpp
+++ b/src/mongo/db/s/migration_coordinator.cpp
@@ -128,9 +128,6 @@ void MigrationCoordinator::startMigration(OperationContext* opCtx) {
     donorDeletionTask.setPending(true);
     const auto currentTime = VectorClock::get(opCtx)->getTime();
     donorDeletionTask.setTimestamp(currentTime.clusterTime().asTimestamp());
-    if (feature_flags::gOrphanTracking.isEnabled(serverGlobalParams.featureCompatibility)) {
-        donorDeletionTask.setNumOrphanDocs(0);
-    }
     migrationutil::persistRangeDeletionTaskLocally(
         opCtx, donorDeletionTask, WriteConcerns::kMajorityWriteConcernShardingTimeout);
 }
diff --git a/src/mongo/db/s/migration_destination_manager.cpp b/src/mongo/db/s/migration_destination_manager.cpp
index e8ebe638187..6f4fe0c2272 100644
--- a/src/mongo/db/s/migration_destination_manager.cpp
+++ b/src/mongo/db/s/migration_destination_manager.cpp
@@ -1289,9 +1289,6 @@ void MigrationDestinationManager::_migrateDriver(OperationContext* outerOpCtx,
             recipientDeletionTask.setPending(true);
             const auto currentTime = VectorClock::get(outerOpCtx)->getTime();
             recipientDeletionTask.setTimestamp(currentTime.clusterTime().asTimestamp());
-            if (feature_flags::gOrphanTracking.isEnabled(serverGlobalParams.featureCompatibility)) {
-                recipientDeletionTask.setNumOrphanDocs(0);
-            }
 
             // It is illegal to wait for write concern with a session checked out, so persist the
             // range deletion task with an immediately satsifiable write concern and then wait for
diff --git a/src/mongo/db/s/migration_util.cpp b/src/mongo/db/s/migration_util.cpp
index ee54cadb56b..a2ec056f48d 100644
--- a/src/mongo/db/s/migration_util.cpp
+++ b/src/mongo/db/s/migration_util.cpp
@@ -700,11 +700,7 @@ void persistUpdatedNumOrphans(OperationContext* opCtx,
                               const UUID& migrationId,
                               const UUID& collectionUuid,
                               long long changeInOrphans) {
-    // TODO (SERVER-63819) Remove numOrphanDocsFieldName field from the query
-    // Add $exists to the query to ensure that on upgrade and downgrade, the numOrphanDocs field
-    // is only updated after the upgrade procedure has populated it with an initial value.
-    BSONObj query = BSON("_id" << migrationId << RangeDeletionTask::kNumOrphanDocsFieldName
-                               << BSON("$exists" << true));
+    BSONObj query = BSON("_id" << migrationId);
     try {
         PersistentTaskStore<RangeDeletionTask> store(NamespaceString::kRangeDeletionNamespace);
         ScopedRangeDeleterLock rangeDeleterLock(opCtx, collectionUuid);
@@ -750,7 +746,7 @@ long long retrieveNumOrphansFromRecipient(OperationContext* opCtx,
     }
     const auto numOrphanDocsElem =
         rangeDeletionResponse.docs[0].getField(RangeDeletionTask::kNumOrphanDocsFieldName);
-    return numOrphanDocsElem ? numOrphanDocsElem.safeNumberLong() : 0;
+    return numOrphanDocsElem.safeNumberLong();
 }
 
 void notifyChangeStreamsOnRecipientFirstChunk(OperationContext* opCtx,
diff --git a/src/mongo/db/s/migration_util_test.cpp b/src/mongo/db/s/migration_util_test.cpp
index 24fb4d3567e..8e6f02043da 100644
--- a/src/mongo/db/s/migration_util_test.cpp
+++ b/src/mongo/db/s/migration_util_test.cpp
@@ -344,7 +344,6 @@ TEST_F(MigrationUtilsTest, TestUpdateNumberOfOrphans) {
     const auto collectionUuid = UUID::gen();
     PersistentTaskStore<RangeDeletionTask> store(NamespaceString::kRangeDeletionNamespace);
     auto rangeDeletionDoc = createDeletionTask(opCtx, kTestNss, collectionUuid, 0, 10);
-    rangeDeletionDoc.setNumOrphanDocs(0);
     store.add(opCtx, rangeDeletionDoc);
 
     migrationutil::persistUpdatedNumOrphans(opCtx, rangeDeletionDoc.getId(), collectionUuid, 5);
diff --git a/src/mongo/db/s/range_deletion_task.idl b/src/mongo/db/s/range_deletion_task.idl
index 2e47651abdb..7d2b90610b9 100644
--- a/src/mongo/db/s/range_deletion_task.idl
+++ b/src/mongo/db/s/range_deletion_task.idl
@@ -84,4 +84,4 @@ structs:
             numOrphanDocs:
                 type: safeInt64
                 description: "The estimated number of orphaned documents in the range"
-                optional: true
+                default: 0
diff --git a/src/mongo/db/s/shard_server_op_observer.cpp b/src/mongo/db/s/shard_server_op_observer.cpp
index ea0908949ee..4f853ddf78b 100644
--- a/src/mongo/db/s/shard_server_op_observer.cpp
+++ b/src/mongo/db/s/shard_server_op_observer.cpp
@@ -275,7 +275,7 @@ void ShardServerOpObserver::onInserts(OperationContext* opCtx,
                     std::make_unique<SubmitRangeDeletionHandler>(opCtx, deletionTask));
             }
 
-            const auto numOrphanDocs = deletionTask.getNumOrphanDocs().value_or(0);
+            const auto numOrphanDocs = deletionTask.getNumOrphanDocs();
             BalancerStatsRegistry::get(opCtx)->onRangeDeletionTaskInsertion(
                 deletionTask.getCollectionUuid(), numOrphanDocs);
         }
@@ -549,7 +549,7 @@ void ShardServerOpObserver::onDelete(OperationContext* opCtx,
         const auto numOrphanDocs = [&] {
             auto numOrphanDocsElem = update_oplog_entry::extractNewValueForField(
                 deletedDoc, RangeDeletionTask::kNumOrphanDocsFieldName);
-            return numOrphanDocsElem ? numOrphanDocsElem.exactNumberLong() : 0;
+            return numOrphanDocsElem.exactNumberLong();
         }();
 
         auto collUuid = [&] {