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From Roi Apelker <Roi.Apel...@amdocs.com>
Subject RE: Indxes and hints
Date Tue, 29 Aug 2017 13:02:07 GMT
Thank you Jason :-)

-----Original Message-----
From: Jason Huynh [mailto:jhuynh@pivotal.io] 
Sent: Monday, August 28, 2017 7:24 PM
To: dev@geode.apache.org
Subject: Re: Indxes and hints

Hi Roi,

Answers are below the questions...

Question 1. Is it true to say, that the query as it is will load all the data values from
the file, since the field C is part of the value, which is already persisted to file?

Depending on if an index is used or not, if an index is used, the values that are part of
the results will need to be loaded to actually return a result.  If an index is not used,
then the all the values would need to be loaded to actually have something to evaluate the
filter criteria on.

Question 2. If I add a hint on A and B, will it mean that there will be a
"2 phase search", first the select on A and B, and then, only on the results, on the field
C? (this way, not all records will be loaded from file, only those that suit the A and B condition)

Depending on the  query, it could use one, or more.  If it's a query with only AND clauses,
it should just choose one and then evaluate the other filters on the subset that is returned
from the index.

Question 3. Is it possible to define an index on a value field? (i.e. not from the key) -
will it work exactly like defining one form the key or are three any limitations? (again,
I am looking to overcome the situation, where as it seems, the records are loaded unnecessarily
from disk)

Yes, indexes can be defined on fields in the value.  It will work the same.


If you are sure you are already using an index in the query and still loading every value
for every execution of that query, there may be something weird going on...

On Sun, Aug 27, 2017 at 2:55 AM Roi Apelker <Roi.Apelker@amdocs.com> wrote:
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