Tonight it happened again, but after ~1 hour the app recovered on its own. There must be something wrong with app engine.
On 20 Sep., 00:08, Bernd Final <[email protected]> wrote: > 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 [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
