| [geomesa-users] question about updates to data and duplicates |
|
We have data that will see updates to its data. These updates can be to any of the fields including the time field as well as the latitude and longitude fields used to create the default Point geometry.
What we have observed is if the datetime changed, even over a month difference, we still just got one record back via WFS regardless of how many were still in the z3 table and the record got updated the z2 and the records tables in accumulo. Again if we updated the latitude value, even a slight change to it, and added the feature again (instead of modify the feature or remove then add), then we got 2 copies of the record that have the same id field that we hint to use for FID. I found an old post that sort of talked to this around how a Versioning Iterator is configured to return 1 record for scan time and both minor and major compactions and that had to so specifically for the Accumulo side of the question.
Then the response went on to talk to the GeoMesa side of it and asked do the 2 copies of a SimpleFeature have the same Feature ID? If yes then GeoMesa will write the same Accumulo keys for the data. If not then different keys will be written. So what does
that mean, Feature ID…is that the field hinted to use for FID or is that the 3 pieces that make up the index key? So why does time field differences not impact duplicates coming back from WFS requests (using z3 index) but changes in latitude and longitude do? So is the recommendation if updates to the latitude/longitude/point data will happen then
to identify the record is changed and either modify or remove/add? We are seeing this in GeoMesa 1.2.7.2 against Accumulo 1.6.2. Thanks, Diane Griffith |