Hi All! I'm trying to figure out the reason of my datastore timeouts. I use master/slave datastore.
As I can see possible reasons are: - contention issues - "A very small number of datastore operations – generally less than 1 in 3000 – will result in a timeout in normal operation" (as per documentation) In my case it is acceptable error rate for background task operations (which retry automatically). For example (today stats) 127.58K tasks caused 192 errors. It is possible some contention errors here. But for user operations sometimes I have very high error rate (89 requests failed from 1.7K with datastore timeout). - I'm pretty sure I'm not trying to update the same entity group in the same minute (not even second) - transaction is small: get by key, put with updated value, run new task to update stats within transaction - I cannot retry operation within 30 seconds user request... I've added retry code - but It fails earlier - I cannot find any error patterns My questions are: 1. If this is a task queue issue - will transaction fail with datastore timeout? 2. Has High Replication datastore any difference in "normal" error rate (1 of 3000 for master/slave)? Just for the test I've created 2 applications (master/slave and HR) and ran my code (~40K task requests and random user actions). But results are not so obvious - master/slave failed 1 time with datastore error - no errors with HR May be due to small amount of data (~200MB in my test, possible only 1 tablet used). In real system I have around 190GB now. The error distribution (today 21/02): <https://lh3.googleusercontent.com/_nXv-kmjg1BQ/TWLXXDQAwrI/AAAAAAAAQno/wK-1Kh2Z_Qw/gae_erors.png> The big issue that these errors are visible to the customers. Any suggestions? Thanks! -- 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.
