Hi Ikai,

Thanks for your clarification, for time being we will create index.

Thanks,
Ravi

On Jun 15, 10:13 pm, "Ikai L (Google)" <[email protected]> wrote:
> Ravi,
>
> There's no ETA for the index traversal optimizations Alfred is talking
> about. We'll try to get it out as quickly as possible. Create the indexes
> for the time being. You can remove them later using the vacuum_indexes tool.
>
>
>
>
>
> On Tue, Jun 15, 2010 at 1:06 AM, Ravi <[email protected]> wrote:
> > Hi Alfred Fuller,
>
> > Thanks for your information, videos gave me lot of information.
> > As per your suggestion I have added few composite index to avoid this
> > exception still index are getting built.
> > As we get exception on some queries, will add those to composite
> > index. But this will eat my lot of CPU quota.
> > Could you please tell me when will this restriction on query will be
> > removed because we will plan our product enhancement accordingly.
>
> > Thanks,
> > Ravi
>
> > On Jun 15, 4:57 am, Alfred Fuller 
> > <[email protected]<arfuller%[email protected]>
>
> > wrote:
> > > Yes, you can create composite indexes that contain columns that are often
> > > queried together. The merge join algorithm will use these indexes to make
> > > queries that include those specific columns more efficient.  Or if you
> > see
> > > this error more often on some queries than others, create composite
> > indexes
> > > for those queries (or the common columns between those queries)
>
> > >http://www.youtube.com/watch?v=ofhEyDBpngMattime 30:30 gives an example
> > of
> > > this.
>
> > > On Mon, Jun 14, 2010 at 7:58 AM, Ravi <[email protected]> wrote:
> > > > Hi Geoffrey Spear,
> > > > Thanks for your clarification.
> > > > We suspected the same reason. Last few days back our data was less
> > > > around 20,000 rows there was no problem.
> > > > Only when more data is added we are facing this problem.
>
> > > > Our table is too large which is around 50 fields/columns and around
> > > > 50,000 rows. Query filter is also dynamically generated (user selects
> > > > few fields and submits).
> > > > Our servlet will query database depending on the user selected fields.
> > > > In this scenario we dont know which fields will be selected by user
> > > > and certainly I cant have composite index for 50 combinations.
>
> > > > Is there any work around for this problem??
>
> > > > Thanks,
> > > > Ravi
>
> > > > On Jun 14, 5:59 pm, Geoffrey Spear <[email protected]> wrote:
> > > > > It's not a problem with indexing, it's a problem with your data.  If
> > > > > you don't add composite indexes, the system will attempt to serve
> > > > > queries that contain only equality filters using a merge-join
> > > > > strategy, which is less efficient than a simple index lookup (with
> > the
> > > > > benefit of not needing to add the indexes, which use space and write-
> > > > > time CPU).  If your data becomes such that the query can not be done
> > > > > efficiently with the merge-join anymore, you'll start to see that
> > > > > exception and you'll need to add a composite index.
>
> > > > > On Jun 12, 2:00 am, Ravi <[email protected]> wrote:
>
> > > > > > Hi Google Team,
>
> > > > > > All these days our application was working fine and we have not
> > > > > > changed any datastore index or codebase of our application.
> > > > > > Everyday we upload new set of data to our application. Today also
> > we
> > > > > > have uploaded new set of data but today after uploading the data we
> > > > > > are getting very strange exception as below:
>
> > > > > > com.google.appengine.api.datastore.DatastoreNeedIndexException: The
> > > > > > built-in indices are not efficient enough for this query and your
> > > > > > data. Please add a composite index for this query..  An index is
> > > > > > missing but we are unable to tell you which one due to a bug in the
> > > > > > App Engine SDK.  If your query only contains equality filters you
> > most
> > > > > > likely need a composite index on all the properties referenced in
> > > > > > those filters.
>
> > > > > > We are worried after seeing the above exception, we dont have any
> > > > > > complex queries, all the queries contain equals to filter (==).
> > > > > > We tested the same set of data and query in our development
> > > > > > environment, it is working fine.
> > > > > > For testing purpose, we uploaded the same set of data to our other
> > > > > > testing appengine applcation, it is working fine there also.
>
> > > > > > Only in our production system, we are getting
> > > > > > DatastoreNeedIndexException.
>
> > > > > > Could you please confirm is there any problem with the datastore
> > > > > > indexing.
> > > > > > Data stored in our production datastore is more than  0.5 GB, will
> > > > > > thee be any problem in indexing if there is high amount of data.
>
> > > > > > Application ID: bigpaisa2.appspot.com
> > > > > > Latest application version:
> > > >http://061102.latest.bigpaisa2.appspot.com
> > > > > > -   In this version DatastoreNeedIndexException is occuring.
>
> > > > > > Please help us as soon as possible.
>
> > > > > > Thanks,
> > > > > > Ravi
>
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> --
> Ikai Lan
> Developer Programs Engineer, Google App Engine
> Blog:http://googleappengine.blogspot.com
> Twitter:http://twitter.com/app_engine
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