ksql | database purpose-built for stream processing applications | Stream Processing library
kandi X-RAY | ksql Summary
kandi X-RAY | ksql Summary
ksqlDB is a database for building stream processing applications on top of Apache Kafka. It is distributed, scalable, reliable, and real-time. ksqlDB combines the power of real-time stream processing with the approachable feel of a relational database through a familiar, lightweight SQL syntax. ksqlDB offers these core primitives:.
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Top functions reviewed by kandi - BETA
- Handles QueryPublisher
- Create an API query holder
- Get the query stream response writer
- Executes a stream query
- Subscribes the query
- Parse KSQLRequest
- Gets a ws materialized query
- Close KSQLDB
- Shutdown additional agents
- Gets a window
- Logs into JAAS login context
- Builds the select expressions
- Visits a FunctionCall node
- Inject a statement
- Handle query
- Prints the description of the function
- Writes the messages to the output stream
- Deserialize CSV data
- Returns the partition locations for the given keys
- Starts the ksqlDB server asynchronously
- Entry point for the downloader
- Merge two lists
- Handles the routing request
- Starts the commands
- Method to execute the connector
- Checks if the given source name and type can be guessed
ksql Key Features
ksql Examples and Code Snippets
Community Discussions
Trending Discussions on ksql
QUESTION
I have a custom UDF that I can pass a struct to:
select my_udf(a.my_data) from MY_STREAM a;
What I would like to do, is pass all info from my stream to that custom UDF:
select my_udf(a) from MY_STREAM a;
That way I can access the row partition, time, offset, etc. Unfortunately, KSQL does not understand my intent:
SELECT column 'A' cannot be resolved
Any idea how I could work around this?
...ANSWER
Answered 2022-Apr-14 at 19:27It's not possible to pass in a full row into a UDF, only columns, and a is the name of the stream, not a column name.
You can change your UDF, to accept multiple parameters, eg, my_udf(my_data, ROWTIME, ROWPARTITION) to pass in an the needed metadata individually.
QUESTION
I currently have a table in KSQL which created by
...ANSWER
Answered 2022-Apr-02 at 15:59In step 2, instead of using the topic cdc_window_table, I should use something like _confluent-ksql-xxx-ksqlquery_CTAS_CDC_WINDOW_TABLE_271-Aggregate-GroupBy-repartition.
This table's changelog topic is automatically created by KSQL when I created the previous table.
You can find this long changelog topic name by using
QUESTION
I have a JSONB field called metadata in a Postgres table. When I use Debezium PostgreSQL Connector to generate CDC, it writes metadata as a string into Kafka.
This one CDC I got in the Kafka topic my_db_server.public.product:
ANSWER
Answered 2022-Apr-01 at 09:08You can access operation using extractjsonfield function like that:
QUESTION
In my local Confluent Platform, I have 1 topic call "FOO_02", I have manually insert some records to it, thus, I can print it from beginning base on the following command:
...ANSWER
Answered 2022-Mar-18 at 09:56I'm presuming that you've already done
QUESTION
I'm using a dockerized version of the Confluent Platform v 7.0.1:
...ANSWER
Answered 2022-Feb-18 at 22:37You may be hitting issues since you are running an old version of ksqlDB's quickstart (0.7.1) with Confluent Platform 7.0.1.
If you check out a quick start like this one: https://ksqldb.io/quickstart-platform.html, things may work better.
I looked for an updated version of that data generator and didn't find it quickly. If you are looking for more info about structured data, give https://docs.ksqldb.io/en/latest/how-to-guides/query-structured-data/ a read.
QUESTION
I have a problem. I can't find a way to create a stream by filtering on the key of a kafka document.
I would like to filter and manipulate the json of a kafka key to retrieve the payload of the following example which corresponds to my couchbase id:
...ksql> print 'cb_bench_products-get_purge' limit 1;
ANSWER
Answered 2022-Mar-04 at 14:26You didn't specify the value part of your message so I've mocked up some data and assumed that it's also JSON. First I load it into a topic to test again:
QUESTION
I've installed latest (7.0.1) version of Confluent platform in standalone mode on Ubuntu virtual machine.
Python producer for Avro formatUsing this sample Avro producer to generate stream from data to Kafka topic (pmu214).
Producer seems to work ok. I'll give full code on request. Producer output:
...ANSWER
Answered 2022-Feb-11 at 14:42If you literally ran the Python sample code, then the key is not Avro, so a failure on the key.converter would be expected, as shown
Error converting message key
QUESTION
https://docs.confluent.io/5.4.1/ksql/docs/developer-guide/syntax-reference.html#struct-overview Confluent docs say they don't accept Properties as a valid field name, but why?
What if I do have a schema with Properties, what can I do then?
ANSWER
Answered 2022-Feb-10 at 18:21It's a keyword/reserved word in the language. I'm not familiar with ksql specifically, but most sql distributions provide backticks to escape references for this reason (and more). Without those, it'd make sense you couldn't use it.
As an example of using backticks in a pretty standard sql statement:
QUESTION
When configuring ksqlDB I can set the option ksql.streams.producer.compression.type which enables compression for ksqlDB's internal producers. Thus when I create a ksqlDB stream, it's output topic will be compressed with the selected compression type.
However, as far as I have understood the compression performance is heavily impacted by how much batching the producer does. Therefore, I wish to be able to configure the batch.size and linger.ms parameters for ksqlDB's producers. Does anyone know if and how these parameters can be set for ksqlDB?
...ANSWER
Answered 2022-Feb-01 at 08:00Thanks to Matthias J Sax for answering my question on the Confluent Community Slack channel: https://app.slack.com/client/T47H7EWH0/threads?cdn_fallback=1
There is an info-box in the documentation. That explains it pretty well:
The underlying producer and consumer clients in ksqlDB's server can be modified with any valid properties. Simply use the form ksql.streams.producer.xxx, ksql.streams.consumer.xxx to pass the property through. For example, ksql.streams.producer.compression.type sets the compression type on the producer.
Source: https://docs.ksqldb.io/en/latest/reference/server-configuration/
QUESTION
My team is using Kafka Confluent (enterprise version) and we are very new to kafka.
We have 2 topic A and B.
Topic A will receive all json messages and formatted by Avro Schema (using URL to schema registry).
By some reasons, The development tool we are using does not support receiving messages from topic A in avro format. We create Topic B and want to use KsqlDB to copy all messages from topic A to topic B and also transform all messages from avro format to normal json format so that we can develop a component that can pick up json messages from topic B.
Could you please show me code to create ksql stream to do that.
...ANSWER
Answered 2022-Jan-21 at 13:38Register the inbound Avro data stream
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