I understand the process of evenly distributing IDs since they are Integer values.. is there a canonized appengine way to evenly distribute key_names?
Just make sure key_name1 and key_name2 don't have their i-th letters "too close" too eachother? How far is far enough? Does doing even distribution matter if you aren't using auto-generated IDs? Thanks for information. On Wed, Feb 17, 2010 at 1:32 PM, Nick Johnson (Google) < [email protected]> wrote: > Hi Ulrich, > > On Wed, Feb 17, 2010 at 5:30 PM, Ulrich <[email protected]>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 [email protected]. >> To unsubscribe from this group, send email to >> [email protected]<google-appengine%[email protected]> >> . >> 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 [email protected]. > To unsubscribe from this group, send email to > [email protected]<google-appengine%[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.
