There actually is one other thing that may be useful - the way
geomesa is implemented, you can sometimes do an appending write,
which will overwrite any existing feature. There are a few caveats
though:
* You have to know the feature ID for the existing feature, and use
the same one
* You can't read the existing feature and modify it, you have to
overwrite the whole thing
* If any of your 'indexable' attributes change, you will end up with
duplicate data. Indexable attributes are generally the default
geometry, date, and any attribute indexed fields
* I've tested this with our Accumulo implementation - other
back-ends may or may not work the same (though I'd expect HBase at
least to work fine)
* It's implementation dependent, so the behavior may change out from
under you unexpectedly (though I would say for the foreseeable
future that's not very likely)
Doing updates this way is also much faster, as it's a single write
instead of a read/delete/write.
Thanks,
Emilio
On 01/22/2018 11:45 AM, Emilio
Lahr-Vivaz wrote:
modifyFeatures may be useful, but it won't add new features, and
it doesn't report back if something changed. In terms of effect,
it's equivalent to the SQL 'update table foo set colA = bar where
colB = baz'.
As you say, I don't believe the geotools API supports upsert. The
equivalent would be something like:
val updater = ds.getFeatureWriter(typeName, filter,
Transaction.AUTO_COMMIT)
if (updater.hasNext) {
// modify update feature
} else {
val appender = ds.getFeatureWriterAppend(typeName,
Transaction.AUTO_COMMIT)
// add to appender
}
If doing batches, you could keep a reference to the appender
instead of creating one each time.
Any implementation we added would essentially be a convenience
wrapper around that. I don't believe there are any major
optimizations we could make, so I'm not sure it's worthwhile to do
something outside the geotools API unless a lot of people want it.
Thanks,
Emilio
On 01/22/2018 10:58 AM, Jim Hughes
wrote:
Hi Jason,
In terms of implementation, upserts would end up being a
delete followed by an insert. I think the GeoTools DataStore
API does have a modifyFeatures call which may provide some of
the convenience you are looking for here.
Cheers,
Jim
On 01/18/2018 02:59 PM, Jason Koh wrote:
Hi,
I wonder if Geomesa is going to have the upsert feature. I
want to update the value of a certain query if the query
pattern exists, else insert. Geotools seems not supporting
this though. I understand it doesn't have to be
prioritized, but just curious.
Thanks!
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