## What changes were proposed in this pull request?
Minor change to kafka integration document for structured streaming.
## How was this patch tested?
N/A, doc change only.
Author: Liang-Chi Hsieh <viirya@gmail.com>
Closes#18550 from viirya/minor-ss-kafka-doc.
## What changes were proposed in this pull request?
Add documentation that describes how to write streaming and batch queries to Kafka.
zsxwing tdas
Please review http://spark.apache.org/contributing.html before opening a pull request.
Author: Tyson Condie <tcondie@gmail.com>
Closes#17246 from tcondie/kafka-write-docs.
## What changes were proposed in this pull request?
Revision to structured-streaming-kafka-integration.md to reflect new Batch query specification and options.
zsxwing tdas
Please review http://spark.apache.org/contributing.html before opening a pull request.
Author: Tyson Condie <tcondie@gmail.com>
Closes#16918 from tcondie/kafka-docs.
## What changes were proposed in this pull request?
There are many locations in the Spark repo where the same word occurs consecutively. Sometimes they are appropriately placed, but many times they are not. This PR removes the inappropriately duplicated words.
## How was this patch tested?
N/A since only docs or comments were updated.
Author: Niranjan Padmanabhan <niranjan.padmanabhan@gmail.com>
Closes#16455 from neurons/np.structure_streaming_doc.
## What changes were proposed in this pull request?
This patch uses `{% highlight lang %}...{% endhighlight %}` to highlight code snippets in the `Structured Streaming Kafka010 integration doc` and the `Spark Streaming Kafka010 integration doc`.
This patch consists of two commits:
- the first commit fixes only the leading spaces -- this is large
- the second commit adds the highlight instructions -- this is much simpler and easier to review
## How was this patch tested?
SKIP_API=1 jekyll build
## Screenshots
**Before**
**After**
Author: Liwei Lin <lwlin7@gmail.com>
Closes#15715 from lw-lin/doc-highlight-code-snippet.
## What changes were proposed in this pull request?
maxOffsetsPerTrigger option for rate limiting, proportionally based on volume of different topicpartitions.
## How was this patch tested?
Added unit test
Author: cody koeninger <cody@koeninger.org>
Closes#15527 from koeninger/SPARK-17813.
## What changes were proposed in this pull request?
startingOffsets takes specific per-topicpartition offsets as a json argument, usable with any consumer strategy
assign with specific topicpartitions as a consumer strategy
## How was this patch tested?
Unit tests
Author: cody koeninger <cody@koeninger.org>
Closes#15504 from koeninger/SPARK-17812.
## What changes were proposed in this pull request?
This PR adds a new project ` external/kafka-0-10-sql` for Structured Streaming Kafka source.
It's based on the design doc: https://docs.google.com/document/d/19t2rWe51x7tq2e5AOfrsM9qb8_m7BRuv9fel9i0PqR8/edit?usp=sharing
tdas did most of work and part of them was inspired by koeninger's work.
### Introduction
The Kafka source is a structured streaming data source to poll data from Kafka. The schema of reading data is as follows:
Column | Type
---- | ----
key | binary
value | binary
topic | string
partition | int
offset | long
timestamp | long
timestampType | int
The source can deal with deleting topics. However, the user should make sure there is no Spark job processing the data when deleting a topic.
### Configuration
The user can use `DataStreamReader.option` to set the following configurations.
Kafka Source's options | value | default | meaning
------ | ------- | ------ | -----
startingOffset | ["earliest", "latest"] | "latest" | The start point when a query is started, either "earliest" which is from the earliest offset, or "latest" which is just from the latest offset. Note: This only applies when a new Streaming query is started, and that resuming will always pick up from where the query left off.
failOnDataLost | [true, false] | true | Whether to fail the query when it's possible that data is lost (e.g., topics are deleted, or offsets are out of range). This may be a false alarm. You can disable it when it doesn't work as you expected.
subscribe | A comma-separated list of topics | (none) | The topic list to subscribe. Only one of "subscribe" and "subscribeParttern" options can be specified for Kafka source.
subscribePattern | Java regex string | (none) | The pattern used to subscribe the topic. Only one of "subscribe" and "subscribeParttern" options can be specified for Kafka source.
kafka.consumer.poll.timeoutMs | long | 512 | The timeout in milliseconds to poll data from Kafka in executors
fetchOffset.numRetries | int | 3 | Number of times to retry before giving up fatch Kafka latest offsets.
fetchOffset.retryIntervalMs | long | 10 | milliseconds to wait before retrying to fetch Kafka offsets
Kafka's own configurations can be set via `DataStreamReader.option` with `kafka.` prefix, e.g, `stream.option("kafka.bootstrap.servers", "host:port")`
### Usage
* Subscribe to 1 topic
```Scala
spark
.readStream
.format("kafka")
.option("kafka.bootstrap.servers", "host:port")
.option("subscribe", "topic1")
.load()
```
* Subscribe to multiple topics
```Scala
spark
.readStream
.format("kafka")
.option("kafka.bootstrap.servers", "host:port")
.option("subscribe", "topic1,topic2")
.load()
```
* Subscribe to a pattern
```Scala
spark
.readStream
.format("kafka")
.option("kafka.bootstrap.servers", "host:port")
.option("subscribePattern", "topic.*")
.load()
```
## How was this patch tested?
The new unit tests.
Author: Shixiong Zhu <shixiong@databricks.com>
Author: Tathagata Das <tathagata.das1565@gmail.com>
Author: Shixiong Zhu <zsxwing@gmail.com>
Author: cody koeninger <cody@koeninger.org>
Closes#15102 from zsxwing/kafka-source.
