JDBCInputFormat preparation with Flink 1.1-SNAPSHOT and Scala 2.11

[Prez Cannady-2]

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: [hidden email]  

GH: https://github.com/opencorrelate  

LI: https://www.linkedin.com/in/revprez  

[Chesnay Schepler]

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: [hidden email]  

GH: https://github.com/opencorrelate  

LI: https://www.linkedin.com/in/revprez  

[Prez Cannady-3]

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: [hidden email]  

GH: https://github.com/opencorrelate  

LI: https://www.linkedin.com/in/revprez  

On Mar 9, 2016, at 3:25 AM, Chesnay Schepler <[hidden email]> 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: [hidden email][hidden email]  

GH: https://github.com/opencorrelate  

LI: https://www.linkedin.com/in/revprez  

[Chesnay Schepler]

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: [hidden email]  

GH: https://github.com/opencorrelate  

LI: https://www.linkedin.com/in/revprez  

On Mar 9, 2016, at 3:25 AM, Chesnay Schepler <[hidden email]> 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: [hidden email]  

GH: https://github.com/opencorrelate  

LI: https://www.linkedin.com/in/revprez  

[Prez Cannady-3]

Thanks.  Need to dive in a bit better, but I did clarify some things in my mind which bear mentioning.

1. Sourcing JDBC data is not a streaming operation, but a batching one.  Which makes sense, since you generally slurp rather than stream relational data, so within the constraints provided you’ll be operating on whole result sets.

2. Kafka is useful for mating batch processes (like slurping a database) with stream ones (reading out the results of a database query then distributed to various processing nodes).

Prez Cannady  

p: 617 500 3378  

e: [hidden email]  

GH: https://github.com/opencorrelate  

LI: https://www.linkedin.com/in/revprez  

On Mar 9, 2016, at 6:46 AM, Prez Cannady <[hidden email]> 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: [hidden email]  

GH: https://github.com/opencorrelate  

LI: https://www.linkedin.com/in/revprez  

On Mar 9, 2016, at 3:25 AM, Chesnay Schepler <[hidden email]> 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: [hidden email][hidden email]  

GH: https://github.com/opencorrelate  

LI: https://www.linkedin.com/in/revprez  

[rmetzger0]

Sorry for joining this discussion late. Maybe this is also interesting for you: http://www.confluent.io/blog/bottled-water-real-time-integration-of-postgresql-and-kafka/

On Wed, Mar 9, 2016 at 1:47 PM, Prez Cannady <[hidden email]> wrote:

Thanks.  Need to dive in a bit better, but I did clarify some things in my mind which bear mentioning.

1. Sourcing JDBC data is not a streaming operation, but a batching one.  Which makes sense, since you generally slurp rather than stream relational data, so within the constraints provided you’ll be operating on whole result sets.

2. Kafka is useful for mating batch processes (like slurping a database) with stream ones (reading out the results of a database query then distributed to various processing nodes).

Prez Cannady  

p: 617 500 3378  

e: [hidden email]  

GH: https://github.com/opencorrelate  

LI: https://www.linkedin.com/in/revprez  

On Mar 9, 2016, at 6:46 AM, Prez Cannady <[hidden email]> 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: [hidden email]  

GH: https://github.com/opencorrelate  

LI: https://www.linkedin.com/in/revprez  

On Mar 9, 2016, at 3:25 AM, Chesnay Schepler <[hidden email]> 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: [hidden email][hidden email]  

GH: https://github.com/opencorrelate  

LI: https://www.linkedin.com/in/revprez