Re: [geomesa-users] Index other than time/location?

[Emilio Lahr-Vivaz <elahrvivaz@xxxxxxxx>]

Hi Simon,

You can index attributes for quick querying. To do this, when you create your simple feature type you need to indicate that you want it to be indexed like so: name:String:index=full. (In addition to 'full', you can specify index=join, which will save some disk space at the cost of query performance).

In addition, make sure that you use our custom simple feature type parser: in scala it is org.locationtech.geomesa.utils.geotools.SimpleFeatureTypes, or we have a java version at org.locationtech.geomesa.utils.interop.SimpleFeatureTypes.

Please note that attribute indices are designed for attributes that have a high cardinality - indexing e.g. a boolean will give you very poor performance. Also, they use a single threaded scan, so if you are trying to return a lot of records at once they will not be particularly fast. There are some other caveats with how a given query will be executed - if you have a more specific use case I can probably give some guidance there.

If you want to add indices to an existing data set, we have a map/reduce job that you can run, details of which are here:

https://github.com/locationtech/geomesa/tree/master/geomesa-jobs#attribute-indexing

Thanks,

On 06/15/2015 08:21 AM, Xu (Simon) Chen wrote:

Hello,

I am curious to know if there is a way to inform geomesa to index on a column in addition to location and time. For example a string column like name and point type.

Thanks!

-Simon

_______________________________________________
geomesa-users mailing list
geomesa-users@xxxxxxxxxxxxxxxx
To change your delivery options, retrieve your password, or unsubscribe from this list, visit
http://www.locationtech.org/mailman/listinfo/geomesa-users