Wolfram -- Thank you for the response.
I will do as you suggest ... access the stale group with a GET to clear up the stale replica. Also, in rare cases, we have seen a get for a single row in the datastore, return an old result and the current result randomly, many days after the item was updated. You can reload the page with the data on it and literally see it flip between the two versions of the row. I assume this is because the row is being retrieved from different replica. Any thoughts on that and how we can resolve it? Thanks again for your help. On Mon, Jun 24, 2013 at 11:27 PM, Wolfram Gürlich <[email protected]>wrote: > Hi James, > > what you see is a combination of two things: (a) indexes are eventually > consistent - meaning that there is a lag between writing and them > reflecting the current state and (b) replication which also happens to be > eventual consistent meaning that not all replicas have the same state. Each > replica (datacenter) has a complete copy of all your data AND all your > indexes. > When you do a query that query will hit exactly one (randomly choosen) > datacenter (replica). So your result set might be stale because that > replica hasn't yet applied all your writes. The next query may give you a > very different result because it hits another replica. > > I've experienced inconsistencies for more than 12 hours which isn't the > regular case though. At least 99.9% of the time inconsistencies will last > for less than a second. But sometimes after REALLY heavy updates (a couple > 100K writes within minutes) I've seen a small portion of entities remaining > stale for hours. > > From what I've seen, most of the time an inconsistency will instantly > vanish (on all replicas) as soon as you access the stale entity group > consistently (doing a GET). The datastore detects the inconsistency and > applies the writes that are still pending on some replica. Never will a > consistent operation (like GET) give you a stale result (provided you > haven't changed your read policy to inconsistent). > > Wolfram > > -- > You received this message because you are subscribed to a topic in the > Google Groups "Google App Engine" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/google-appengine/OkCjziExt74/unsubscribe > . > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/google-appengine. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/google-appengine. For more options, visit https://groups.google.com/groups/opt_out.
