now that i look back to my mail i may have given you the wrong idea
about the prototype; to make sure we are on the same page:
the only thing it enables is using the JDBCInputFormat without providing
a separate TypeInformation. Still works with tuples, not POJO's.
you can find the prototype here:
https://github.com/zentol/flink/tree/3445_jdbc
The JDBCInputFormat there implements ResultTypeQueryable. WIthin
getProducedType it executes a dummy query, reads the ResultSetMetaData
and generates a TypeInfo from it.
On 09.03.2016 12:46, Prez Cannady wrote:
I suspected as much (the tuple size limitation). Creating my own
InputFormat seems to be the best solution, but before i go down that
rabbit hole I wanted to see at least a semi-trivial working example of
JDBCInputFormat with Scala 2.11.
I’d appreciate a look at that prototype if its publicly available
(even if it is Java). I might glean a hint from it.
Prez Cannady
p: 617 500 3378
e: revp...@opencorrelate.org <mailto:revp...@opencorrelate.org>
GH: https://github.com/opencorrelate
LI: https://www.linkedin.com/in/revprez
On Mar 9, 2016, at 3:25 AM, Chesnay Schepler <ches...@apache.org
<mailto:ches...@apache.org>> wrote:
you can always create your own InputFormat, but there is no
AbstractJDBCInputFormat if that's what you were looking for.
When you say arbitrary tuple size, do you mean a) a size greater than
25, or b) tuples of different sizes?
If a) unless you are fine with using nested tuples you won't get
around the tuple size limitation. Since the user has to be aware of
the nesting (since the fields can be accessed directly via tuple.f0
etc), this can't really be done in a general-purpose fashion.
If b) this will straight-up not work with tuples.
You could use POJO's though. then you could also group by column names.
I'm not sure about Scala, but in the Java Stream API you can pass the
InputFormat and the TypeInformation into createInput.
I've recently did a prototype where the input type is determined
automatically by querying the database. If this is a problem for you
feel free to ping me.
On 09.03.2016 03:17, Prez Cannady wrote:
I’m attempting to create a stream using JDBCInputFormat. Objective
is to convert each record into a tuple and then serialize for input
into a Kafka topic. Here’s what I have so far.
```
val env = StreamExecutionEnvironment.getExecutionEnvironment
val inputFormat = JDBCInputFormat.buildJDBCInputFormat()
.setDrivername("org.postgresql.Driver")
.setDBUrl("jdbc:postgresql:test")
.setQuery("select name from persons")
.finish()
val stream : DataStream[Tuple1[String]] = env.createInput(...)
```
I think this is essentially what I want to do. It would be nice if
I could return tuples of arbitrary length, but reading the code
suggests I have to commit to a defined arity. So I have some questions.
1. Is there a better way to read from a database (i.e., defining my
own `InputFormat` using Slick)?
2. To get the above example working, what should I supply to
`createInput`?
Prez Cannady
p: 617 500 3378
e: revp...@opencorrelate.org
GH: https://github.com/opencorrelate
LI: https://www.linkedin.com/in/revprez
