On Thu, Jan 28, 2010 at 11:14 AM, Max <[email protected]> wrote: > Bump! > > In my opinion, the 2nd one performs better but use more storage. > Because the first one fan out (n + m) copies whereas the second one > fans out (n * m) copies. > > This is just MY THEORY. Please correct me if I am wrong.
thanks Max :) does anybody have a pointer to a specification where I could look up the exact time and space consumption of both querys on GAE? Thanks, Raphael > > Thanks a lot, > > Max > > On 1月28日, 上午1時06分, Raphael André Bauer <[email protected]> > wrote: >> Hi everybody, >> >> Suppose you have to entities. Entity1 has one list, Entity2 has two lists: >> >> Entity1 >> List<String> tags_and_timestamps >> >> Entity2 >> List<String> tags >> List<String> timestamps >> >> (I hope the peseudocode is ok - the questions is a general datastore >> question and not dependent on JPA/JDO or low-level api). >> >> Then I want to merge join my entities based on two properties: a >> timestamp and on a tag. >> >> Entity1 is a stupid entity simply storing everyhting in one list. >> So I merge join on one list: >> tags_and_timestamps == timestamp AND tags_and_timestamps == tag >> >> Entity2 is separates both values, so I merge join on: >> timestamps == timestamp AND tags == tag >> >> The question is now: What is more efficient on the GAE datastore? >> Separating the values into different lists or storing everything in >> one list? >> >> Thanks a lot, >> >> Raphael > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine for Java" 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-java?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Google App Engine for Java" 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-java?hl=en.
