SERVER-34385 Unit tests for secondary reads during oplog application

1 files changed, 83 insertions, 0 deletions

diff --git a/jstests/replsets/secondary_reads_timestamp_visibility.js b/jstests/replsets/secondary_reads_timestamp_visibility.js
new file mode 100644
index 00000000000..47b7163d7f5
--- /dev/null
+++ b/jstests/replsets/secondary_reads_timestamp_visibility.js
@@ -0,0 +1,83 @@
+/**
+ * Tests that reads on a secondary during batch application only see changes that occur at the last
+ * applied timestamp, whichis advanced at the completion of each batch.
+ *
+ * This test uses a failpoint to block right before batch application finishes, while holding the
+ * PBWM lock, and before advancing the last applied timestamp for readers.
+ *
+ */
+(function() {
+    "use strict";
+
+    load('jstests/replsets/libs/secondary_reads_test.js');
+
+    const name = "secondaryReadsTimestampVisibility";
+    const collName = "testColl";
+    let secondaryReadsTest = new SecondaryReadsTest(name);
+    let replSet = secondaryReadsTest.getReplset();
+
+    let primaryDB = secondaryReadsTest.getPrimaryDB();
+    let secondaryDB = secondaryReadsTest.getSecondaryDB();
+
+    let primaryColl = primaryDB.getCollection(collName);
+
+    // Create a collection and an index. Insert some data.
+    primaryDB.runCommand({drop: collName});
+    assert.commandWorked(primaryDB.runCommand({create: collName}));
+    assert.commandWorked(primaryDB.runCommand(
+        {createIndexes: collName, indexes: [{key: {y: 1}, name: "y_1", unique: true}]}));
+    for (let i = 0; i < 100; i++) {
+        assert.commandWorked(primaryColl.insert({_id: i, x: 0, y: i + 1}));
+    }
+
+    replSet.awaitReplication();
+
+    // Sanity check.
+    assert.eq(secondaryDB.getCollection(collName).find({x: 0}).itcount(), 100);
+    assert.eq(secondaryDB.getCollection(collName).find({y: {$gte: 1, $lt: 101}}).itcount(), 100);
+
+    // Prevent a batch from completing on the secondary.
+    let pauseAwait = secondaryReadsTest.pauseSecondaryBatchApplication();
+
+    // Update x to 1 in each document with default writeConcern and make sure we see the correct
+    // data on the primary.
+    let updates = [];
+    for (let i = 0; i < 100; i++) {
+        updates[i] = {q: {_id: i}, u: {x: 1, y: i}};
+    }
+    assert.commandWorked(primaryDB.runCommand({update: collName, updates: updates}));
+    assert.eq(primaryColl.find({x: 1}).itcount(), 100);
+    assert.eq(primaryColl.find({y: {$gte: 0, $lt: 100}}).itcount(), 100);
+
+    // Wait for the batch application to pause.
+    pauseAwait();
+
+    let levels = ["local", "available", "majority"];
+
+    // We should see the previous, un-replicated state on the secondary with every readconcern.
+    for (let i in levels) {
+        assert.eq(secondaryDB.getCollection(collName).find({x: 0}).readConcern(levels[i]).itcount(),
+                  100);
+        assert.eq(secondaryDB.getCollection(collName).find({x: 1}).readConcern(levels[i]).itcount(),
+                  0);
+        assert.eq(secondaryDB.getCollection(collName)
+                      .find({y: {$gte: 1, $lt: 101}})
+                      .readConcern(levels[i])
+                      .itcount(),
+                  100);
+    }
+
+    // Disable the failpoint and let the batch complete.
+    secondaryReadsTest.resumeSecondaryBatchApplication();
+
+    replSet.awaitReplication();
+
+    for (let i in levels) {
+        // We should see the previous state on the secondary with every readconcern.
+        assert.eq(secondaryDB.getCollection(collName).find({x: 0}).readConcern(levels[i]).itcount(),
+                  0);
+        assert.eq(secondaryDB.getCollection(collName).find({x: 1}).readConcern(levels[i]).itcount(),
+                  100);
+    }
+    secondaryReadsTest.stop();
+})();