Deserialization Cost of ListProperty

[MajorProgamming]

I was recently watching a Google I/O video (I believe it was by Brett
Slatkin), and I noticed that he was trying to avert the
Deserialization Cost of ListProperties. I was wondering how "bad" that
cost is, and how big the list has to be in order to see that cost?
(e.g. let's say I know the list will contain a maximum of 75. Would
that be something to worry about?)

Thanks,

[Nick Johnson (Google)]

Hi MajorProgramming,

Deserializing ListProperties can be expensive - nearly equivalent to
the cost of deserializing an equivalent number of non-list properties.
For exact performance details, I would recommend benchmarking it. A
list of size 75 may or may not be problematic, depending on your
application.

Also bear in mind that every entry in a ListProperty corresponds to an
index entry (unless you marked it as indexed=False), which increases
overhead when doing a put().

-Nick Johnson

--
Nick Johnson, App Engine Developer Programs Engineer
Google Ireland Ltd. :: Registered in Dublin, Ireland, Registration
Number: 368047