I've had this issue for 5 or 6 times already. My app is running for a long time and I've had no problems so far, except this one:
Out of nowhere, 20-30 seconds latency and only serving HTTP 500 errors for 99,9% of all requests. In most Servlets (yeah I'm using Java if that matters) I'm accessing the memcache, sometimes the datastore (Master/Slave). As you can imagine the app is totally unusable when this happens. When it occured the first time I didn't to any special, just waited for a couple of hours until the app recovered on it's own. Dashboard Milliseconds/Request Chart: Yesterday: http://bit.ly/pSF66E Last 30 Days: http://bit.ly/nYdZ2S When it happend again and again I tried to figure out what's going on, luckily I had some kind of Admin-Servlet deployed which allowed me to clear the entire memcache. Tried it, and voila, everything back to normal. - The memcache size was up to 1.3-1.5 MB in total (I did a rough estimation with the ByteArrayOutputStream trick). 12 Objects are stored in the memcache. Each Object is POJO which implements Serializable and contains some Strings, Integers and ArrayLists. - My first idea was to minimize the memory usage, because I though I was hitting the 1MB limit. At this time I didn't know the limit is for each object not for the whole cache, anyway I was able to reduce the size by 30-40% so the size is now about 800kb - 1MB - I'm running a cron job which cleans out garbage of the memcache. - This is how I access the memcache on every request: CacheManager.getInstance().getCacheFactory().createCache(Collections.emptyMap()); - I'm using put and get Methods for storing / retrieving, - The key length is about 160 bytes Unfortunately I was not able to solve this issue yet, I would be very happy for ANY input. -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. 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.
