SERVER-37240 Enable dbhash background thread for enableMajorityReadConcern:false variant

(cherry picked from commit 0991709cf60677b183cc0362e432c095d9ed185f)

2 files changed, 27 insertions, 13 deletions

diff --git a/buildscripts/resmokelib/testing/hooks/dbhash_background.py b/buildscripts/resmokelib/testing/hooks/dbhash_background.py
index 7d4790fe1fd..b8122f458b8 100644
--- a/buildscripts/resmokelib/testing/hooks/dbhash_background.py
+++ b/buildscripts/resmokelib/testing/hooks/dbhash_background.py
@@ -36,11 +36,6 @@ class CheckReplDBHashInBackground(jsfile.JSHook):
                              " doesn't support snapshot reads.",
                              server_status["storageEngine"]["name"])
             return
-        if not server_status["storageEngine"].get("supportsCommittedReads", False):
-            self.logger.info("Not enabling the background thread because '%s' storage engine"
-                             " doesn't support committed reads.",
-                             server_status["storageEngine"]["name"])
-            return
         if not server_status["storageEngine"].get("persistent", False):
             self.logger.info("Not enabling the background thread because '%s' storage engine"
                              " is not persistent.", server_status["storageEngine"]["name"])
diff --git a/jstests/hooks/run_check_repl_dbhash_background.js b/jstests/hooks/run_check_repl_dbhash_background.js
index 83079541e8d..d3029ea27ba 100644
--- a/jstests/hooks/run_check_repl_dbhash_background.js
+++ b/jstests/hooks/run_check_repl_dbhash_background.js
@@ -136,14 +136,33 @@
             // doesn't exceed the node's notion of the latest clusterTime.
             session.advanceClusterTime(sessions[0].getClusterTime());
 
-            // We do an afterClusterTime read on a nonexistent collection to wait for the secondary
-            // to have applied up to 'clusterTime' and advanced its majority commit point.
-            assert.commandWorked(db.runCommand({
-                find: 'run_check_repl_dbhash_background',
-                readConcern: {level: 'majority', afterClusterTime: clusterTime},
-                limit: 1,
-                singleBatch: true,
-            }));
+            // We need to make sure the secondary has applied up to 'clusterTime' and advanced its
+            // majority commit point.
+
+            if (jsTest.options().enableMajorityReadConcern !== false) {
+                // If majority reads are supported, we can issue an afterClusterTime read on
+                // a nonexistent collection and wait on it. This has the advantage of being easier
+                // to debug in case of a timeout.
+                assert.commandWorked(db.runCommand({
+                    find: 'run_check_repl_dbhash_background',
+                    readConcern: {level: 'majority', afterClusterTime: clusterTime},
+                    limit: 1,
+                    singleBatch: true,
+                }));
+            } else {
+                // If majority reads are not supported, then our only option is to poll for the
+                // lastOpCommitted on the secondary to catch up.
+                assert.soon(
+                    function() {
+                        const rsStatus =
+                            assert.commandWorked(db.adminCommand({replSetGetStatus: 1}));
+                        const committedOpTime = rsStatus.optimes.lastCommittedOpTime;
+                        return bsonWoCompare(committedOpTime.ts, clusterTime) >= 0;
+                    },
+                    "The majority commit point on secondary " + i + " failed to reach " +
+                        clusterTime,
+                    10 * 60 * 1000);
+            }
         }
     };