SERVER-46002 Attach core read mirroring functionality

1 files changed, 124 insertions, 0 deletions

diff --git a/jstests/noPassthrough/mirror_reads.js b/jstests/noPassthrough/mirror_reads.js
new file mode 100644
index 00000000000..692a9ada958
--- /dev/null
+++ b/jstests/noPassthrough/mirror_reads.js
@@ -0,0 +1,124 @@
+/**
+ * Verify that mirroredReads happen in response to setParameters.mirroredReads
+ *
+ * @tags: [requires_replication]
+ */
+
+(function() {
+"use strict";
+
+function setParameter({rst, value}) {
+    return rst.getPrimary().adminCommand({setParameter: 1, mirrorReads: value});
+}
+
+const kBurstCount = 1000;
+const kDbName = "mirrored_reads_test";
+const kCollName = "test";
+
+function sendAndCheckReads({rst, cmd, minRate, maxRate}) {
+    let startMirroredReads =
+        rst.getPrimary().getDB(kDbName).serverStatus({mirroredReads: 1}).mirroredReads;
+
+    jsTestLog(`Sending ${kBurstCount} request burst of ${tojson(cmd)} to primary`);
+
+    // Blast out a set of trivial reads
+    for (var i = 0; i < kBurstCount; ++i) {
+        rst.getPrimary().getDB(kDbName).runCommand(cmd);
+    }
+
+    jsTestLog(`Verifying ${tojson(cmd)} was mirrored`);
+
+    // Verify that the reads have been observed on the primary
+    {
+        let currentMirroredReads =
+            rst.getPrimary().getDB(kDbName).serverStatus({mirroredReads: 1}).mirroredReads;
+        assert.eq(startMirroredReads.seen + kBurstCount, currentMirroredReads.seen);
+    }
+
+    // Verify that the reads mirrored to the secondaries have responded
+    assert.soon(() => {
+        let currentMirroredReads =
+            rst.getPrimary().getDB(kDbName).serverStatus({mirroredReads: 1}).mirroredReads;
+
+        let readsSeen = currentMirroredReads.seen - startMirroredReads.seen;
+        let readsMirrored = currentMirroredReads.resolved - startMirroredReads.resolved;
+
+        let numNodes = rst.getSecondaries().length;
+        jsTestLog(`Seen ${readsSeen} requests; ` +
+                  `verified ${readsMirrored / 2} requests ` +
+                  `x ${numNodes} nodes`);
+
+        let rate = readsMirrored / readsSeen / numNodes;
+        return (rate >= minRate) && (rate <= maxRate);
+    }, "Did not verify all requests within time limit", 10000);
+
+    jsTestLog(`Verified ${tojson(cmd)} was mirrored`);
+}
+
+function verifyMirrorReads(rst, cmd) {
+    {
+        jsTestLog(`Verifying disabled read mirroring with ${tojson(cmd)}`);
+        let samplingRate = 0.0;
+
+        assert.commandWorked(setParameter({rst: rst, value: {samplingRate: samplingRate}}));
+        sendAndCheckReads({rst: rst, cmd: cmd, minRate: samplingRate, maxRate: samplingRate});
+    }
+
+    {
+        jsTestLog(`Verifying full read mirroring with ${tojson(cmd)}`);
+        let samplingRate = 1.0;
+
+        assert.commandWorked(setParameter({rst: rst, value: {samplingRate: samplingRate}}));
+        sendAndCheckReads({rst: rst, cmd: cmd, minRate: samplingRate, maxRate: samplingRate});
+    }
+
+    {
+        jsTestLog(`Verifying partial read mirroring with ${tojson(cmd)}`);
+        let samplingRate = 0.5;
+        let gaussDeviation = .34;
+        let max = samplingRate + gaussDeviation;
+        let min = samplingRate - gaussDeviation;
+
+        assert.commandWorked(setParameter({rst: rst, value: {samplingRate: samplingRate}}));
+        sendAndCheckReads({rst: rst, cmd: cmd, minRate: min, maxRate: max});
+    }
+}
+
+{
+    const rst = new ReplSetTest({
+        nodes: 3,
+        nodeOptions:
+            {setParameter: {"failpoint.mirrorMaestroExpectsResponse": tojson({mode: "alwaysOn"})}}
+    });
+    rst.startSet();
+    rst.initiateWithHighElectionTimeout();
+
+    jsTestLog(`Attempting invalid mirrorReads parameters`);
+    assert.commandFailed(setParameter({rst: rst, value: 0.5}));
+    assert.commandFailed(setParameter({rst: rst, value: "half"}));
+    assert.commandFailed(setParameter({rst: rst, value: {samplingRate: -1.0}}));
+    assert.commandFailed(setParameter({rst: rst, value: {samplingRate: 1.01}}));
+    assert.commandFailed(setParameter({rst: rst, value: {somplingRate: 1.0}}));
+
+    // Put in a datum
+    {
+        let ret =
+            rst.getPrimary().getDB(kDbName).runCommand({insert: kCollName, documents: [{x: 1}]});
+        assert.commandWorked(ret);
+    }
+
+    jsTestLog("Verifying mirrored reads for 'find' commands");
+    verifyMirrorReads(rst, {find: kCollName, filter: {}});
+
+    jsTestLog("Verifying mirrored reads for 'count' commands");
+    verifyMirrorReads(rst, {count: kCollName, query: {}});
+
+    jsTestLog("Verifying mirrored reads for 'distinct' commands");
+    verifyMirrorReads(rst, {distinct: kCollName, key: "x"});
+
+    jsTestLog("Verifying mirrored reads for 'findAndModify' commands");
+    verifyMirrorReads(rst, {findAndModify: kCollName, query: {}, update: {'$inc': {x: 1}}});
+
+    rst.stopSet();
+}
+})();