Hi,
I admit that sometimes it would be useful to know the total number of features
on the WFS layer. I am also rather sure that WFS standard says that
resultType=hits must show the same feature count than resultType=results so
the current behavior should remain as default. What Andrea says about filter is
true already, filter must be applied for resultType=hits and it can be heavy.
Especially with Oracle because sometimes "AND rownum< maxFeatures+1" is applied
last.
-Jukka Rahkonen-
Andrea Aime wrote:
On Tue, Jan 22, 2013 at 6:53 AM, Geoff Williams
<[email protected]<mailto:[email protected]>> wrote:
Hi List,
I'm running a geoserver instance with a 10K max feature limit. A colleague of
mine is interested in obtaining feature counts for a datasource containing 30K+
features.
He can find this information by making multiple requests with resultType=hits
and using the built-in geoserver paging but it would be a lot nicer if he could
just make one request and get an accurate count with the server ignoring the
configured maximum feature limit for the purposes of an accurate feature count.
I see. The limit is working on count too for good reasons:
- counting can be expensive (can take minutes) if you have datasets with tens
or hundreds of millions of records
- the filter expressed in the WFS request can make it much worse, for example,
you might filter on an
attribute that's not indexed, or use WFS 2.0 to ask for an expensive join
Is this something that's easy to change? Would there be any interest in a
patch to allow this?
I believe it could be of interest, but it would have to be configurable, either
a separate max value
for the count operation or a flag disabling the existing max for the count
operation.
The classes to be modified would be WFSInfo, WFSInfoImpl (the configuration
bits), the WFSAdminPage,
and the GetFeature class to take into account the above configurations.
Since this is an API change, it has to take place on the unstable series before
(which, starting
from today, means the 2.4.x series, the 2.3.x series is entering hardening
today in preparation
for the 2.3.0 release in a couple of months).
If you want to persue this please discuss the changes you want to make on the
geoserver-devel
list.
Cheers
Andrea
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