Hi Ulrich, On Wed, Feb 17, 2010 at 5:30 PM, Ulrich <mierendo...@googlemail.com> wrote:
> Hi, > > I have read the following > "Timeouts due to datastore issues --- [...] The most common example of > this occurs when you are rapidly inserting a large number of entities > of the same kind, with auto-generated IDs. In this case, most inserts > hit the same range of the same tablet, and the single tablet server is > overwhelmed with writes. [...] If this does affect your app, the > easiest solution is to use more evenly distributed IDs instead of the > auto-allocated ones [...]" > ( http://code.google.com/appengine/articles/handling_datastore_errors.html > ) > > Let's say I am having a model "Parent" and a model "Child". For Parent > entities, I use key names that are evenly distributed. For Child > entities, I use auto-generated key IDs and _no_ key names, but all > Child entities are children of Parent entities, so the paths to the > children contain the evenly distributes key names of the parents. > If I have many write operations on children that are in the same > entity group, the described error could occur. But what happens if my > write operations are on children that are in different entity groups? > Their IDs are auto-generated and not evenly distributed, but their > paths contain the evenly distributed key names. > Good question! The point being made in the article refers to the global distribution of the complete key, so writes to these children will be well distributed, and you won't have to worry about this source of contention. -Nick Johnson > > -- > 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-appeng...@googlegroups.com. > To unsubscribe from this group, send email to > google-appengine+unsubscr...@googlegroups.com<google-appengine%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en. > > -- Nick Johnson, Developer Programs Engineer, App Engine Google Ireland Ltd. :: Registered in Dublin, Ireland, Registration Number: 368047 -- 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-appeng...@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.
