Just burned several days with Google Enterprise Support trying to troubleshoot intermittent long latencies; unnecessary dynamic instance starts; and failures during dynamic instance starts on a multi-threaded GAE Java app running on Master/Slave (MS) data store.
My typical app latencies on MS were under 1 second per request. Periodically I'd see 5-20 second delays with very little traffic. My app starts in under 3 seconds (stripes/slim3), so when instances failed to start in 30 seconds, I suspected a GAE issue. After many attempts to resolve the issue, we finally decided to to try switching to the High Replication (HR) data store. All of the issues disappeared!!! The long latencies were all gone. My traffic was easily being served with a single instance. No more phantom dynamic instances. No more instance start crashes. I just volume tested my app. My median request went from 2.5 seconds on MS to under 1 second on HR with 1000 simultaneous users. Previously I was paying for 3 always-on instances. With HR enabled, there was no need for any always-on instances. So if High Replication is faster, and more stable, why should Google spend valuable resources supporting Master/Slave? Is the cost savings of MS worth all the issues it creates? Not for me. If you're experiencing similar problems on MS I highly recommend giving HR a shot. FYI, migration to HR was trivial: - created a new app id, - deployed my app to the new id, - used my app to initialize the data (this will be problematic for some), - had google point the old app id to the new app id. now serving from the original URL. -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To view this discussion on the web visit https://groups.google.com/d/msg/google-appengine/-/XCUAKZ5E1LYJ. To post to this group, send email to google-appengine@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
