Drools workbench (business-central) requests timing out

Question

I have installed business central along with Keycloak authentication using MySQL as a database for storing Keycloak's data. The business-central workbench and Keycloak server are behind Nginx. While working on the workbench some of the request timeout giving a 504 error code. The whole business central UI freezes and the user is not able to do anything after that.

The urls that error out in 504 are like: https://{host}:{port}/business-central/out.43601-24741.erraiBus?z=105&clientId=43601-24741

Other details about the setup are as below:

Java: 1.8.0_242

Business central version: 7.34.Final

Keycloak version: 9.0.0

MySql: 8

Java options for business central: -Xms1024M -Xmx2048M -XX:MaxPermSize=2048M -XX:MaxHeapSize=2048M

Note: All of this setup of mine is on a 4GB EC2 instance.

Any help on this issue would be appreciated.

EDIT: I have checked the access_log.log and it looks like the server takes more than 45 sec to process the request. Here is a log:

"POST /business-central/in.93979-28827.erraiBus?z=15&clientId=93979-28827&wait=1 HTTP/1.1" 200 "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36"i 45001 45.001

EDIT 2: Here is a sample request data that is sent:

[{"CommandType":"CDIEvent","BeanType":"org.kie.workbench.common.screens.library.api.ProjectCountUpdate","BeanReference":{"^EncodedType":"org.kie.workbench.common.screens.library.api.ProjectCountUpdate","^ObjectID":"1","count":1,"space":{"^EncodedType":"org.uberfire.spaces.Space","^ObjectID":"2","name":"Fraud_Team"}},"FromClient":"1","ToSubject":"cdi.event:Dispatcher"},{"ToSubject":"org.kie.workbench.common.screens.library.api.LibraryService:RPC","CommandType":"getAllUsers:","Qualifiers":{"^EncodedType":"java.util.ArrayList","^ObjectID":"1","^Value":[]},"MethodParms":{"^EncodedType":"java.util.Arrays$ArrayList","^ObjectID":"2","^Value":[]},"ReplyTo":"org.kie.workbench.common.screens.library.api.LibraryService:RPC.getAllUsers::94:RespondTo:RPC","ErrorTo":"org.kie.workbench.common.screens.library.api.LibraryService:RPC.getAllUsers::94:Errors:RPC"}]

The URL hit is : business-central/in.59966-45867.erraiBus?z=56&clientId=59966-45867&wait=1

It took more than a minute to process.

Answer 1

Problem Description

I had this same problem on 7.38.0. The problem, I believe, is that ERRAI seems to keep rolling 45 second requests open between the client and server to ensure communication is open. For me, Nginx had a default socket timeout of 30s which meant that it was returning a 504 gateway timeout for these requests, when in actuality they weren't "stuck". This would only happen if you didn't do anything within Business Central for 30 seconds, as otherwise the request would close and a new one takes over. I feel like ERRAI should really be able to recover from such a scenario, but anyway.

Solution

For me, I updated the socket timeout of my Nginx server to 60s such that the 45s requests didn't get timed out by Nginx. I believe this is equiavalent to the proxy_read_timeout config in Nginx.

If you can't touch your Nginx config, it seemed like there may also be a way to turn off the server to client communication as outlined here: https://docs.jboss.org/errai/4.0.0.Beta3/errai/reference/html_single/#sid-59146643_BusLifecycle-TurningServerCommunicationOnandOff . I didn't test this as I didn't need to, but it may be an option.