1 files changed, 75 insertions, 17 deletions

diff --git a/jstests/replsets/dbhash_read_at_cluster_time.js b/jstests/replsets/dbhash_read_at_cluster_time.js
index e8c42b4e57f..99a4517f926 100644
--- a/jstests/replsets/dbhash_read_at_cluster_time.js
+++ b/jstests/replsets/dbhash_read_at_cluster_time.js
@@ -1,7 +1,8 @@
 /**
- * Tests that "$_internalReadAtClusterTime" is supported by the "dbHash" command.
+ * Tests that "$_internalReadAtClusterTime" and "snapshot" level
+ * read concern are supported by the "dbHash" command.
  *
- * @tags: [uses_transactions]
+ * @tags: [uses_transactions, requires_fcv_46, requires_majority_read_concern]
  */
 (function() {
 "use strict";
@@ -18,7 +19,6 @@ const secondary = rst.getSecondary();
 
 const session = primary.startSession({causalConsistency: false});
 const db = session.getDatabase("test");
-let txnNumber = 0;
 
 // We prevent the replica set from advancing oldest_timestamp. This ensures that the snapshot
 // associated with 'clusterTime' is retained for the duration of this test.
@@ -38,7 +38,17 @@ let res = assert.commandWorked(db.runCommand({
     $_internalReadAtClusterTime: clusterTime,
 }));
 
-const hash1 = {
+const internalAtClusterTimeHashBefore = {
+    collections: res.collections,
+    md5: res.md5
+};
+
+res = assert.commandWorked(db.runCommand({
+    dbHash: 1,
+    readConcern: {level: "snapshot", atClusterTime: clusterTime},
+}));
+
+const atClusterTimeHashBefore = {
     collections: res.collections,
     md5: res.md5
 };
@@ -50,32 +60,65 @@ const hash1 = {
 // on the secondary.
 assert.commandWorked(db.mycoll.insert({_id: 2}, {writeConcern: {w: "majority"}}));
 
-// However, using $_internalReadAtClusterTime to read at the opTime of the first insert should
-// return the same md5sum as it did originally.
+// However, using $_internalReadAtClusterTime or snapshot read concern to read at the opTime of the
+// first insert should return the same md5sum as it did originally.
 res = assert.commandWorked(db.runCommand({
     dbHash: 1,
     $_internalReadAtClusterTime: clusterTime,
 }));
 
-const hash2 = {
+const internalAtClusterTimeHashAfter = {
     collections: res.collections,
     md5: res.md5
 };
-assert.eq(hash1, hash2, "primary returned different dbhash after second insert");
+
+res = assert.commandWorked(db.runCommand({
+    dbHash: 1,
+    readConcern: {level: "snapshot", atClusterTime: clusterTime},
+}));
+
+const atClusterTimeHashAfter = {
+    collections: res.collections,
+    md5: res.md5
+};
+
+assert.eq(internalAtClusterTimeHashBefore,
+          internalAtClusterTimeHashAfter,
+          "primary returned different dbhash after " +
+              "second insert while using $_internalReadAtClusterTime");
+assert.eq(atClusterTimeHashBefore,
+          atClusterTimeHashAfter,
+          "primary returned different dbhash after " +
+              "second insert while using \"snapshot\" level read concern");
 
 {
     const secondarySession = secondary.startSession({causalConsistency: false});
     const secondaryDB = secondarySession.getDatabase("test");
 
-    // Using $_internalReadAtClusterTime to read at the opTime of the first insert should return
-    // the same md5sum on the secondary as it did on the primary.
+    // Using $_internalReadAtClusterTime or snapshot read concern to read at the opTime
+    // of the first insert should return the same md5sum on the secondary as it did on the primary.
     res = assert.commandWorked(secondaryDB.runCommand({
         dbHash: 1,
         $_internalReadAtClusterTime: clusterTime,
     }));
 
-    const secondaryHash = {collections: res.collections, md5: res.md5};
-    assert.eq(hash1, secondaryHash, "primary and secondary have different dbhash");
+    const internalAtClusterTimeSecondaryHash = {collections: res.collections, md5: res.md5};
+
+    res = assert.commandWorked(secondaryDB.runCommand({
+        dbHash: 1,
+        readConcern: {level: "snapshot", atClusterTime: clusterTime},
+    }));
+
+    const atClusterTimeSecondaryHash = {collections: res.collections, md5: res.md5};
+
+    assert.eq(internalAtClusterTimeHashBefore,
+              internalAtClusterTimeSecondaryHash,
+              "primary and secondary have different dbhash " +
+                  "while using $_internalReadAtClusterTime.");
+    assert.eq(atClusterTimeHashBefore,
+              atClusterTimeSecondaryHash,
+              "primary returned different dbhash " +
+                  "while using \"snapshot\" level read concern");
 }
 
 {
@@ -88,19 +131,34 @@ assert.eq(hash1, hash2, "primary returned different dbhash after second insert")
     assert.commandWorked(otherDB.mycoll.insert({_id: 3}));
 
     // It should be possible to run the "dbHash" command with "$_internalReadAtClusterTime"
-    // concurrently.
+    // or snapshot read concern concurrently.
     res = assert.commandWorked(db.runCommand({
         dbHash: 1,
         $_internalReadAtClusterTime: clusterTime,
     }));
 
-    const hash3 = {collections: res.collections, md5: res.md5};
-    assert.eq(hash1, hash3, "primary returned different dbhash after third insert");
+    const concurrentInternalAtClusterTimeHash = {collections: res.collections, md5: res.md5};
+
+    res = assert.commandWorked(db.runCommand({
+        dbHash: 1,
+        readConcern: {level: "snapshot", atClusterTime: clusterTime},
+    }));
+
+    const concurrentAtClusterTimeHash = {collections: res.collections, md5: res.md5};
+
+    assert.eq(internalAtClusterTimeHashBefore,
+              concurrentInternalAtClusterTimeHash,
+              "primary returned different dbhash after " +
+                  "third insert while using $_internalReadAtClusterTime.");
+    assert.eq(atClusterTimeHashBefore,
+              concurrentAtClusterTimeHash,
+              "primary returned different dbhash after " +
+                  "third insert while using \"snapshot\" level read concern");
 
     // However, the "dbHash" command should block behind the transaction if
     // "$_internalReadAtClusterTime" wasn't specified.
-    res = assert.commandFailedWithCode(db.runCommand({dbHash: 1, maxTimeMS: 1000}),
-                                       ErrorCodes.MaxTimeMSExpired);
+    assert.commandFailedWithCode(db.runCommand({dbHash: 1, maxTimeMS: 1000}),
+                                 ErrorCodes.MaxTimeMSExpired);
 
     assert.commandWorked(otherSession.abortTransaction_forTesting());
     otherSession.endSession();