JAVA high frequent gc - com.mongodb.connection.AsynchronousSocketChannelStream$BasicCompletionHandler EATs CPU

[Kenjee]

i found a bug using "io.vertx.ext.mongo.MongoClient". If MongoDB is unavailable for a minute or less a minute the VertxInstance runs into many small GCs and eats CPU. While MongoDB is back only restart helps.

while profiling this problem locally i found "com.mongodb.connection.AsynchronousSocketChannelStream$BasicCompletionHandler" causing the GCs and this uses up to 40% CPU usage. Before disconnection CPU usage was near 0% because i only read periodic from empty mongodb.

TestCase:
MongoClient client = MongoClient.createShared(vertx, this.mongoConfig);
// config is: {"mongo": {"host": "127.0.0.1","port": 27017,"db_name": "notification"}}
Verticle start contains
"this.timerID = vertx.setPeriodic(TimeUtils.MINUTE_IN_MILLISECONDS, INotificationHandler.create(vertx, config()));" and handler reads data by using client

seems to be a problem with

• Issues for mongoDB Java Driver
• https://jira.mongodb.org/browse/JAVA-1881
• https://jira.mongodb.org/browse/JAVA-1825
• should be fixed with version 3.0.3, 3.1.0

Possible Solution

• upgrade the dependencies for http://mvnrepository.com/artifact/org.mongodb/mongodb-driver-async
• groupId: org.mongodb
• artifactId: mongodb-driver-async
• version: newest

[karianna]

Seems like a simple enough fix - PRs welcome!