SERVER-45565: Modified Oplog Batcher behavior to process large transaction oplog entries in separate batches

 create mode 100644 jstests/noPassthrough/large_txn_correctness.js

1 files changed, 55 insertions, 0 deletions

diff --git a/jstests/noPassthrough/large_txn_correctness.js b/jstests/noPassthrough/large_txn_correctness.js
new file mode 100644
index 00000000000..5f240dd3cca
--- /dev/null
+++ b/jstests/noPassthrough/large_txn_correctness.js
@@ -0,0 +1,55 @@
+/**
+ * This test serves to ensure that the oplog batcher behavior correctly processes large transactions
+ * so that it does not cause any correctness problems.
+ *
+ * @tags: [requires_journaling]
+ */
+(function() {
+"use strict";
+load("jstests/core/txns/libs/prepare_helpers.js");
+
+// Declare constants.
+const DB_NAME = "db_large_txn_correctness";
+const COLL_NAME = "db_large_txn_correctness";
+
+// Make a large document of size 'numMB' so that it can easily fill up an oplog entry.
+const makeLargeDoc = numMB => new Array(numMB * 1024 * 1024).join('a');
+
+// Spin up a replica set.
+const replSet = new ReplSetTest({nodes: 1});
+replSet.startSet();
+replSet.initiate();
+const primary = replSet.getPrimary();
+
+const session = primary.startSession();
+
+// Creating a collection so the first test can just test if regular CRUD operations work.
+session.getDatabase(DB_NAME).createCollection(COLL_NAME);
+
+let commitRes;
+
+try {
+    // Perform a large transaction (>16MB) with only CRUD operations to ensure that nothing
+    // fundamental is broken.
+    session.startTransaction();
+    session.getDatabase(DB_NAME)[COLL_NAME].insert({doc: makeLargeDoc(10)});
+    session.getDatabase(DB_NAME)[COLL_NAME].insert({doc: makeLargeDoc(10)});
+    commitRes = session.commitTransaction_forTesting();
+    assert.eq(1, commitRes.ok);
+
+    // Ensure that the collection has been dropped so that collection creation can be tested
+    // in a txn.
+    session.getDatabase(DB_NAME)[COLL_NAME].drop();
+
+    // Create a large transaction (>16MB) with a command and ensure that it works.
+    session.startTransaction();
+    session.getDatabase(DB_NAME).createCollection(COLL_NAME);
+    session.getDatabase(DB_NAME)[COLL_NAME].insert({doc: makeLargeDoc(10)});
+    session.getDatabase(DB_NAME)[COLL_NAME].insert({doc: makeLargeDoc(10)});
+    commitRes = session.commitTransaction_forTesting();
+    assert.eq(1, commitRes.ok);
+} finally {
+    session.endSession();
+    replSet.stopSet();
+}
+})();