Hi David, Entities are stored in the datastore as Protocol Buffers. The size of individual entities is computed by counting the length of each field, while the metadata is the total size of the Entity Protocol Buffers, less the total length of the fields stored in it.
Each field imposes some overhead of its own, in addition to some per-entity and per-index overhead. Together, this accounts for the high overhead you're seeing. -Nick Johnson On Thu, Oct 15, 2009 at 4:24 AM, David W. <[email protected]> wrote: > > Hi there, > > Firstly, the new Datastore statistics are really wonderful, and > finally I can delete all those test applications I've been accruing > this past year. :) > > The new statistics however raise a curious issue: in one of my > applications, I have a very simple kind ("EmailAddressBlock") whose > only field is a DateTimeProperty and main data is stored in the > key_name - usually no more than 20 bytes. > > Looking at the stats for this kind, I see that each entity is taking > up on average 150 bytes – of which 84% is spent on metadata. I'm > wondering if there is more detail available for the metadata; does > this include single property index costs? It seems rather high - given > that these entities are only storing about 30 bytes of unique data > (and use just one single property index). > > Does the metadata cost scale with field count/type, or is it constant? > I presume the cost of storing the key and its path are part of it. > > Thanks, > > > David > > > -- 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] For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~----------~----~----~----~------~----~------~--~---
