I’ve tried the “apply AQLfunction” idea, but got an NullPointException:
java.lang.NullPointerException
at
org.apache.asterix.aql.translator.AqlTranslator.getFeedJointKey(AqlTranslator.java:2268)
at
org.apache.asterix.aql.translator.AqlTranslator.getFeedConnectionRequest(AqlTranslator.java:2214)
at
org.apache.asterix.aql.translator.AqlTranslator.handleConnectFeedStatement(AqlTranslator.java:2130)
at
org.apache.asterix.aql.translator.AqlTranslator.compileAndExecute(AqlTranslator.java:362)
at
org.apache.asterix.api.http.servlet.APIServlet.doPost(APIServlet.java:114)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:754)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
at
org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:546)
at
org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:483)
at
org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231)
at
org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:970)
at
org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:411)
at
org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:192)
at
org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:904)
at
org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
at
org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:110)
at org.eclipse.jetty.server.Server.handle(Server.java:347)
at
org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.java:439)
at
org.eclipse.jetty.server.HttpConnection$RequestHandler.content(HttpConnection.java:924)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:781)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:220)
at
org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:43)
at
org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:545)
at
org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:43)
at
org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:529)
at java.lang.Thread.run(Thread.java:745)
The ddl that I was using is here:
https://gist.githubusercontent.com/JavierJia/ca596df82ffdd456001f/raw/ea86f9ad1531a68c3ecf9036ef5b69976893149d/feed-ddl.aql
<https://gist.githubusercontent.com/JavierJia/ca596df82ffdd456001f/raw/ea86f9ad1531a68c3ecf9036ef5b69976893149d/feed-ddl.aql>
Anyone has any idea? Thank you!
> On Oct 30, 2015, at 12:30 AM, Heri Ramampiaro <[email protected]> wrote:
>
> Although I haven’t tested this (I have mostly used & created java-based
> UDFs),
> one can execute AQL calls from within a UDF. Feeds allows functions to
> execute arbitrary AQL statements (DDL, DMLs etc). I.e., I believe what
> you are trying to do is possible.
>
> For example you could do:
> (Given that you have a rec. type called Tweet, and a dataset ProcessedTweets
>
> create feed CoordTwitterFeed if not exists
> using “push_twitter" (("type-name"="Tweet”))
> apply function find-intersection;
>
> (Here "find-intersection” is an AQL function that does the step specified
> under 2)).
>
> To do nr. 3 the easiest way is to have a modified version of the “hashTag”
> (let’s call this “tweetlocator”). Java-based UDF (see my previous message
> with the
> TweetLib example). You can then connect this as a secondary feed, connected
> to
> “CoordTwitterFeed”.
>
> E.g.:
> create secondary feed ProcessedTwitterFeed from feed CoordTwitterFeed
> apply function “tweelib#tweetlocator";
>
> Thereafter you can connect the feeds to appropriate datasets.
>
> (Since the find-intersection is an AQL function, you can also call
> “tweelib#tweetlocator”
> inside this function).
>
> Best,
> -heri
>
>> On Oct 30, 2015, at 12:18 AM, Young-Seok Kim <[email protected]> wrote:
>>
>> I'm not sure whether the following UDF is possible or not, but hopefully it
>> is.
>> What we're trying to do is to have the following UDF.
>>
>> The UDF
>> 1) accepts an incoming tweet record through a feed job as an input and then
>> 2) takes a field, more specifically, coordinate field value from the tweet
>> record and sends a spatial-intersect query using the coordinate in order to
>> find out the corresponding county of the coordinates (we have created
>> AsterixDB instance which stores US county shapes records into a dataset and
>> created R-tree index on the polygon field of it, so the query will return
>> the county effectively using the R-tree index)
>> 3) creates a new tweet record consisting of the original record's fields +
>> the returned county value
>> 4) ingests to a tweet dataset in the AsterixDB instance.
>>
>> Can we have such an UDF?
>>
>> Best,
>> Young-Seok
>>
>>
>> On Thu, Oct 29, 2015 at 3:53 PM, Heri Ramampiaro <[email protected]> wrote:
>>
>>>>
>>>> 2. Can we use AQL function in those kind of feed UDFs?
>>>
>>> Can you give an example of what you are trying to do?
>>> I.e do you want to run an AQL inside a UDF or use an AQL function as a
>>> UDF connected to a running feed?
>>>
>>> -heri
>
Best,
Jianfeng Jia
PhD Candidate of Computer Science
University of California, Irvine
