So I'd say don't worry about it unless you actually hit this problem. If you do know you'll hit it, see if you have a way to "shard" the timestamp, by account, user, or region, etc..., to relieve some of the pressure. If you must have a global timestamp, I'd say keep it as simple as possible, until you hit the issue. At that point you can figure out a fix.
When I have timestamps on high write-rate entities that are non-critical, for example "expiration" times that are used only for cleanup, I'll sometimes add a random jitter of several hours to spread the writes out a bit. I'd be surprised if changing it by a few seconds helped much -- but it could. Keep in mind, there will already be some degree of randomness since the instance clocks have some slight variation. If you're hitting this issue, I'd give it a shot though. If it works it could at least buy you some time to get a better fix. I don't think there is a fixed number of rows per shard. I think it is split up by data size, and I don't think the exact number is publicly documented. Maybe you can roughly figure it out via experimentation. Robert On Wed, Feb 1, 2012 at 02:28, WGuerlich <[email protected]> wrote: > I know, I'm going to hit the write limit with a timestamp I need to update > on every write and which needs to be indexed. > > As an alternative to sharding: What do you think about adding time jitter to > the timestamp, that is, changing time randomly by a couple seconds? In my > application the timestamp being off by a couple senconds wouldn't pose a > problem. > > Now what I need to know is: How many index entries can I expect to go into > one tablet? This is needed to estimate the amount of jitter necessary to > avoid hitting the same tablet on every write. > > Any insights on this? > > Wolfram > > -- > 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/-/r0SVTq6i4iEJ. > > 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. -- 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.
