SERVER-58988 Avoid sync source selection cycle during primary catchup.

3 files changed, 38 insertions, 12 deletions

diff --git a/src/mongo/rpc/metadata/oplog_query_metadata.cpp b/src/mongo/rpc/metadata/oplog_query_metadata.cpp
index 65d600dab00..f810662ded7 100644
--- a/src/mongo/rpc/metadata/oplog_query_metadata.cpp
+++ b/src/mongo/rpc/metadata/oplog_query_metadata.cpp
@@ -50,6 +50,7 @@ const char kLastCommittedWallFieldName[] = "lastCommittedWall";
 const char kLastOpAppliedFieldName[] = "lastOpApplied";
 const char kPrimaryIndexFieldName[] = "primaryIndex";
 const char kSyncSourceIndexFieldName[] = "syncSourceIndex";
+const char kSyncSourceHostFieldName[] = "syncSourceHost";
 const char kRBIDFieldName[] = "rbid";
 
 }  // unnamed namespace
@@ -60,12 +61,14 @@ OplogQueryMetadata::OplogQueryMetadata(OpTimeAndWallTime lastOpCommitted,
                                        OpTime lastOpApplied,
                                        int rbid,
                                        int currentPrimaryIndex,
-                                       int currentSyncSourceIndex)
+                                       int currentSyncSourceIndex,
+                                       std::string currentSyncSourceHost)
     : _lastOpCommitted(std::move(lastOpCommitted)),
       _lastOpApplied(std::move(lastOpApplied)),
       _rbid(rbid),
       _currentPrimaryIndex(currentPrimaryIndex),
-      _currentSyncSourceIndex(currentSyncSourceIndex) {}
+      _currentSyncSourceIndex(currentSyncSourceIndex),
+      _currentSyncSourceHost(currentSyncSourceHost) {}
 
 StatusWith<OplogQueryMetadata> OplogQueryMetadata::readFromMetadata(const BSONObj& metadataObj) {
     BSONElement oqMetadataElement;
@@ -86,6 +89,14 @@ StatusWith<OplogQueryMetadata> OplogQueryMetadata::readFromMetadata(const BSONOb
     if (!status.isOK())
         return status;
 
+    std::string syncSourceHost;
+    status = bsonExtractStringField(oqMetadataObj, kSyncSourceHostFieldName, &syncSourceHost);
+    // SyncSourceHost might not be set in older versions, checking NoSuchKey error
+    // for backward compatibility.
+    // TODO SERVER-59732: Remove the compatibility check once 6.0 is released.
+    if (!status.isOK() && status.code() != ErrorCodes::NoSuchKey)
+        return status;
+
     long long rbid;
     status = bsonExtractIntegerField(oqMetadataObj, kRBIDFieldName, &rbid);
     if (!status.isOK())
@@ -110,7 +121,8 @@ StatusWith<OplogQueryMetadata> OplogQueryMetadata::readFromMetadata(const BSONOb
     if (!status.isOK())
         return status;
 
-    return OplogQueryMetadata(lastOpCommitted, lastOpApplied, rbid, primaryIndex, syncSourceIndex);
+    return OplogQueryMetadata(
+        lastOpCommitted, lastOpApplied, rbid, primaryIndex, syncSourceIndex, syncSourceHost);
 }
 
 Status OplogQueryMetadata::writeToMetadata(BSONObjBuilder* builder) const {
@@ -121,6 +133,7 @@ Status OplogQueryMetadata::writeToMetadata(BSONObjBuilder* builder) const {
     oqMetadataBuilder.append(kRBIDFieldName, _rbid);
     oqMetadataBuilder.append(kPrimaryIndexFieldName, _currentPrimaryIndex);
     oqMetadataBuilder.append(kSyncSourceIndexFieldName, _currentSyncSourceIndex);
+    oqMetadataBuilder.append(kSyncSourceHostFieldName, _currentSyncSourceHost);
     oqMetadataBuilder.doneFast();
 
     return Status::OK();
@@ -131,6 +144,7 @@ std::string OplogQueryMetadata::toString() const {
     output << "OplogQueryMetadata";
     output << " Primary Index: " << _currentPrimaryIndex;
     output << " Sync Source Index: " << _currentSyncSourceIndex;
+    output << " Sync Source Host: " << _currentSyncSourceHost;
     output << " RBID: " << _rbid;
     output << " Last Op Committed: " << _lastOpCommitted.toString();
     output << " Last Op Applied: " << _lastOpApplied.toString();
diff --git a/src/mongo/rpc/metadata/oplog_query_metadata.h b/src/mongo/rpc/metadata/oplog_query_metadata.h
index 205569a4f31..bd08f6a8b39 100644
--- a/src/mongo/rpc/metadata/oplog_query_metadata.h
+++ b/src/mongo/rpc/metadata/oplog_query_metadata.h
@@ -57,7 +57,8 @@ public:
                        repl::OpTime lastOpApplied,
                        int rbid,
                        int currentPrimaryIndex,
-                       int currentSyncSourceIndex);
+                       int currentSyncSourceIndex,
+                       std::string currentSyncSourceHost);
 
     /**
      * format:
@@ -106,6 +107,14 @@ public:
     }
 
     /**
+     * Returns the host of the sync source of the sender.
+     * Returns empty string if it has no sync source.
+     */
+    std::string getSyncSourceHost() const {
+        return _currentSyncSourceHost;
+    }
+
+    /**
      * Returns the current rbid of the sender.
      */
     int getRBID() const {
@@ -123,6 +132,7 @@ private:
     int _rbid = -1;
     int _currentPrimaryIndex = kNoPrimary;
     int _currentSyncSourceIndex = -1;
+    std::string _currentSyncSourceHost;
 };
 
 }  // namespace rpc
diff --git a/src/mongo/rpc/metadata/oplog_query_metadata_test.cpp b/src/mongo/rpc/metadata/oplog_query_metadata_test.cpp
index 6d7218e83fc..f0515ac100f 100644
--- a/src/mongo/rpc/metadata/oplog_query_metadata_test.cpp
+++ b/src/mongo/rpc/metadata/oplog_query_metadata_test.cpp
@@ -43,7 +43,7 @@ TEST(ReplResponseMetadataTest, OplogQueryMetadataRoundtrip) {
     OpTime opTime1(Timestamp(1234, 100), 5);
     Date_t committedWall = Date_t() + Seconds(opTime1.getSecs());
     OpTime opTime2(Timestamp(7777, 101), 6);
-    OplogQueryMetadata metadata({opTime1, committedWall}, opTime2, 6, 12, -1);
+    OplogQueryMetadata metadata({opTime1, committedWall}, opTime2, 6, 12, -1, "");
 
     ASSERT_EQ(opTime1, metadata.getLastOpCommitted().opTime);
     ASSERT_EQ(committedWall, metadata.getLastOpCommitted().wallTime);
@@ -53,12 +53,14 @@ TEST(ReplResponseMetadataTest, OplogQueryMetadataRoundtrip) {
     BSONObjBuilder builder;
     metadata.writeToMetadata(&builder).transitional_ignore();
 
-    BSONObj expectedObj(BSON(
-        kOplogQueryMetadataFieldName << BSON(
-            "lastOpCommitted" << BSON("ts" << opTime1.getTimestamp() << "t" << opTime1.getTerm())
-                              << "lastCommittedWall" << committedWall << "lastOpApplied"
-                              << BSON("ts" << opTime2.getTimestamp() << "t" << opTime2.getTerm())
-                              << "rbid" << 6 << "primaryIndex" << 12 << "syncSourceIndex" << -1)));
+    BSONObj expectedObj(
+        BSON(kOplogQueryMetadataFieldName
+             << BSON("lastOpCommitted"
+                     << BSON("ts" << opTime1.getTimestamp() << "t" << opTime1.getTerm())
+                     << "lastCommittedWall" << committedWall << "lastOpApplied"
+                     << BSON("ts" << opTime2.getTimestamp() << "t" << opTime2.getTerm()) << "rbid"
+                     << 6 << "primaryIndex" << 12 << "syncSourceIndex" << -1 << "syncSourceHost"
+                     << "")));
 
     BSONObj serializedObj = builder.obj();
     ASSERT_BSONOBJ_EQ(expectedObj, serializedObj);
@@ -89,7 +91,7 @@ TEST(ReplResponseMetadataTest, OplogQueryMetadataRoundtrip) {
 TEST(ReplResponseMetadataTest, OplogQueryMetadataHasPrimaryIndex) {
     for (auto [currentPrimaryIndex, hasPrimaryIndex] :
          std::vector<std::pair<int, bool>>{{-1, false}, {0, true}, {1, true}}) {
-        OplogQueryMetadata oqm({OpTime(), Date_t()}, OpTime(), 1, currentPrimaryIndex, -1);
+        OplogQueryMetadata oqm({OpTime(), Date_t()}, OpTime(), 1, currentPrimaryIndex, -1, "");
         ASSERT_EQUALS(hasPrimaryIndex, oqm.hasPrimaryIndex());
     }
 }