Thanks Alfred. That's the clearest definition of datastore write operations I've seen to-date.
The delta aspect is super-cool and I'm glad to hear it, however, it makes my accounting for our large number of datastore write operations even more out of whack - while we might be updating entities, we're certainly not changing many/all of the indexed properties. The search continues.... j On Sep 6, 4:18 pm, Alfred Fuller <arfuller+appeng...@google.com> wrote: > A datastore write op != an entity put/delete. It is actually (entity + > |index deltas|). > > For example if you have a Kind with 3 indexed properties and 1 composite > index the number of write ops to put a new entity would be: > 1 entity + 1 kind index + (1 ascending + 1 descending) * 3 indexed > properties + 1 composite index value = 9 write ops > > if you change a single property on an existing entity it will be: > 1 entity + (2 ascending changes + 2 descending changes) * 1 indexed property > changed + 2 composite index values changed = 7 write ops > (the change must remove the old value and add the new value for each index) > > deleting the entity will cost the same a creating it (9 write ops) > > It is important to note that these costs have not changed in the new pricing > model, they were just obfuscated in the old model in the form of cpu hours. > Hope this clears it up. > > - Alfred > > On Tue, Sep 6, 2011 at 2:09 PM, Jason Collins > <jason.a.coll...@gmail.com>wrote: > > > > > > > > > Also, not setting indexed=False on your attributes leads to an > > unexpectedly high number of datastore writes. Each attribute without > > indexed=False will yield two more datastore write operations (asc, > > desc), I believe. > > > Even still, we're trying to account for the large number of datastore > > write ops.... > > > j > > > On Sep 6, 3:05 pm, Jason Collins <jason.a.coll...@gmail.com> wrote: > > > We are seeing a lot more datastore write operations than we can > > > account for (375M / day). Still trying to get to the bottom of it > > > because it makes for a scary line item on the new sample bills. We > > > haven't looked closely at read operations yet because the writes > > > dwarfs it. > > > > This blog post outlines some unexpected read statistics: > >http://point7.wordpress.com/2011/09/03/the-amazing-story-of-appengine... > > > . I think that using offset with your queries (instead of cursors) > > > could lead to an inflated number of reads. > > > > Aside, I'm really surprised that datastore reads cost 70% of a write. > > > I would have expected perhaps an order of magnitude cheaper. > > > > j > > > > On Sep 6, 7:57 am, Richard Druce <contactd...@gmail.com> wrote: > > > > > With the appengine pricing changes, we've been paying attention to our > > > > datastore puts. According to the pricing comparison chart we're making > > 2.18 > > > > million puts a day. This seems a lot higher than expected. We receive > > about > > > > 0.6 queries per second which means that each request is making about 60 > > > > puts!! > > > > > Using the sample code for db profilinghttp:// > > code.google.com/appengine/articles/hooks.htmlwemeasured this for a > > > > day and the most we counted was ~14,000 which seems more reasonable. > > Does > > > > anyone have experience with something similar on their site? > > > > Thanks, > > > > Richard > > > -- > > 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-appengine@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. -- 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-appengine@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.
