perf(NODE-6452): Optimize CommandStartedEvent and CommandSucceededEvent constructors

src/cmap/command_monitoring_events.ts

@@ -6,7 +6,7 @@ import {
   LEGACY_HELLO_COMMAND,
   LEGACY_HELLO_COMMAND_CAMEL_CASE
 } from '../constants';
-import { calculateDurationInMs, deepCopy } from '../utils';
+import { calculateDurationInMs } from '../utils';
 import {
   DocumentSequence,
   OpMsgRequest,
@@ -254,7 +254,7 @@ const OP_QUERY_KEYS = [
 /** Extract the actual command from the query, possibly up-converting if it's a legacy format */
 function extractCommand(command: WriteProtocolMessageType): Document {
   if (command instanceof OpMsgRequest) {
-    const cmd = deepCopy(command.command);
+    const cmd = { ...command.command };
     // For OP_MSG with payload type 1 we need to pull the documents
     // array out of the document sequence for monitoring.
     if (cmd.ops instanceof DocumentSequence) {
@@ -276,15 +276,15 @@ function extractCommand(command: WriteProtocolMessageType): Document {
       result = { find: collectionName(command) };
       Object.keys(LEGACY_FIND_QUERY_MAP).forEach(key => {
         if (command.query[key] != null) {
-          result[LEGACY_FIND_QUERY_MAP[key]] = deepCopy(command.query[key]);
+          result[LEGACY_FIND_QUERY_MAP[key]] = { ...command.query[key] };
         }
       });
     }
 
     Object.keys(LEGACY_FIND_OPTIONS_MAP).forEach(key => {
       const legacyKey = key as keyof typeof LEGACY_FIND_OPTIONS_MAP;
       if (command[legacyKey] != null) {
-        result[LEGACY_FIND_OPTIONS_MAP[legacyKey]] = deepCopy(command[legacyKey]);
+        result[LEGACY_FIND_OPTIONS_MAP[legacyKey]] = command[legacyKey];
       }
     });
 
@@ -304,19 +304,13 @@ function extractCommand(command: WriteProtocolMessageType): Document {
     return result;
   }
 
-  const clonedQuery: Record<string, unknown> = {};
-  const clonedCommand: Record<string, unknown> = {};
+  let clonedQuery: Record<string, unknown> = {};
+  const clonedCommand: Record<string, unknown> = { ...command };
   if (command.query) {
-    for (const k in command.query) {
-      clonedQuery[k] = deepCopy(command.query[k]);
-    }
+    clonedQuery = { ...command.query };
     clonedCommand.query = clonedQuery;
   }
 
-  for (const k in command) {
-    if (k === 'query') continue;
-    clonedCommand[k] = deepCopy((command as unknown as Record<string, unknown>)[k]);
-  }
   return command.query ? clonedQuery : clonedCommand;
 }
 
@@ -326,22 +320,22 @@ function extractReply(command: WriteProtocolMessageType, reply?: Document) {
   }
 
   if (command instanceof OpMsgRequest) {
-    return deepCopy(reply.result ? reply.result : reply);
+    return reply.result ? reply.result : reply;
   }
 
   // is this a legacy find command?
   if (command.query && command.query.$query != null) {
     return {
       ok: 1,
       cursor: {
-        id: deepCopy(reply.cursorId),
+        id: reply.cursorId,
         ns: namespace(command),
-        firstBatch: deepCopy(reply.documents)
+        firstBatch: reply.documents
       }
     };
   }
 
-  return deepCopy(reply.result ? reply.result : reply);
+  return reply.result ? reply.result : reply;
 }
 
 function extractConnectionDetails(connection: Connection) {

test/integration/command-logging-and-monitoring/command_monitoring.test.ts

@@ -617,35 +617,5 @@ describe('Command Monitoring', function () {
     afterEach(function (done) {
       client.close(done);
     });
-
-    // NODE-1502
-    it('should not allow mutation of internal state from commands returned by event monitoring', function () {
-      const started = [];
-      const succeeded = [];
-      client.on('commandStarted', filterForCommands('insert', started));
-      client.on('commandSucceeded', filterForCommands('insert', succeeded));
-      const documentToInsert = { a: { b: 1 } };
-      const db = client.db(this.configuration.db);
-      return db
-        .collection('apm_test')
-        .insertOne(documentToInsert)
-        .then(r => {
-          expect(r).to.have.property('insertedId').that.is.an('object');
-          expect(started).to.have.lengthOf(1);
-          // Check if contents of returned document are equal to document inserted (by value)
-          expect(documentToInsert).to.deep.equal(started[0].command.documents[0]);
-          // Check if the returned document is a clone of the original. This confirms that the
-          // reference is not the same.
-          expect(documentToInsert !== started[0].command.documents[0]).to.equal(true);
-          expect(documentToInsert.a !== started[0].command.documents[0].a).to.equal(true);
-
-          started[0].command.documents[0].a.b = 2;
-          expect(documentToInsert.a.b).to.equal(1);
-
-          expect(started[0].commandName).to.equal('insert');
-          expect(started[0].command.insert).to.equal('apm_test');
-          expect(succeeded).to.have.lengthOf(1);
-        });
-    });
   });
 });