// Tests multi-document transactions metrics are still correct after 'killSessions'.
// @tags: [uses_transactions]
(function() {
"use strict";

// Verifies that the given value of the transaction metrics is incremented in the way we expect.
function verifyMetricsChange(initialStats, newStats, valueName, expectedIncrement) {
    assert.eq(initialStats[valueName] + expectedIncrement,
              newStats[valueName],
              "expected " + valueName + " to increase by " + expectedIncrement +
                  ".\nInitial stats: " + tojson(initialStats) + "; New stats: " + tojson(newStats));
}

// Set up the replica set and enable majority read concern for atClusterTime snapshot reads.
const rst = new ReplSetTest({nodes: 1, nodeOptions: {enableMajorityReadConcern: "true"}});
rst.startSet();
rst.initiate();

const dbName = "test";
const collName = "server_transactions_metrics_kill_sessions";
const testDB = rst.getPrimary().getDB(dbName);
assert.commandWorked(testDB.runCommand({create: collName, writeConcern: {w: "majority"}}));

const sessionOptions = {
    causalConsistency: false
};
let session = testDB.getMongo().startSession(sessionOptions);
let sessionDb = session.getDatabase(dbName);

let initialMetrics = assert.commandWorked(testDB.adminCommand({serverStatus: 1})).transactions;

jsTest.log("Start a transaction.");
session.startTransaction();
assert.commandWorked(sessionDb.runCommand({find: collName}));

let newMetrics = assert.commandWorked(testDB.adminCommand({serverStatus: 1})).transactions;
verifyMetricsChange(initialMetrics, newMetrics, "currentActive", 0);
verifyMetricsChange(initialMetrics, newMetrics, "currentInactive", 1);
verifyMetricsChange(initialMetrics, newMetrics, "currentOpen", 1);

jsTest.log("Kill session " + tojson(session.getSessionId()) + ".");
assert.commandWorked(testDB.runCommand({killSessions: [session.getSessionId()]}));

newMetrics = assert.commandWorked(testDB.adminCommand({serverStatus: 1})).transactions;
verifyMetricsChange(initialMetrics, newMetrics, "currentActive", 0);
verifyMetricsChange(initialMetrics, newMetrics, "currentInactive", 0);
verifyMetricsChange(initialMetrics, newMetrics, "currentOpen", 0);
verifyMetricsChange(initialMetrics, newMetrics, "totalCommitted", 0);
verifyMetricsChange(initialMetrics, newMetrics, "totalAborted", 1);
verifyMetricsChange(initialMetrics, newMetrics, "totalStarted", 1);

session.endSession();

session = testDB.getMongo().startSession(sessionOptions);
sessionDb = session.getDatabase(dbName);

jsTest.log("Start a snapshot transaction at a time that is too old.");
session.startTransaction({readConcern: {level: "snapshot", atClusterTime: Timestamp(1, 1)}});
// Operation runs unstashTransactionResources() and throws prior to onUnstash(). As a result,
// the transaction will be implicitly aborted.
assert.commandFailedWithCode(sessionDb.runCommand({find: collName}), ErrorCodes.SnapshotTooOld);

newMetrics = assert.commandWorked(testDB.adminCommand({serverStatus: 1})).transactions;
verifyMetricsChange(initialMetrics, newMetrics, "currentActive", 0);
verifyMetricsChange(initialMetrics, newMetrics, "currentInactive", 0);
verifyMetricsChange(initialMetrics, newMetrics, "currentOpen", 0);

// Kill the session that threw exception before.
jsTest.log("Kill session " + tojson(session.getSessionId()) + ".");
assert.commandWorked(testDB.runCommand({killSessions: [session.getSessionId()]}));

newMetrics = assert.commandWorked(testDB.adminCommand({serverStatus: 1})).transactions;
verifyMetricsChange(initialMetrics, newMetrics, "currentActive", 0);
verifyMetricsChange(initialMetrics, newMetrics, "currentInactive", 0);
verifyMetricsChange(initialMetrics, newMetrics, "currentOpen", 0);
verifyMetricsChange(initialMetrics, newMetrics, "totalCommitted", 0);
verifyMetricsChange(initialMetrics, newMetrics, "totalAborted", 2);
verifyMetricsChange(initialMetrics, newMetrics, "totalStarted", 2);

session.endSession();

rst.stopSet();
}());