ksql | 易学教程

Data is duplicated when I create a flattened stream

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问题 I have a stream deriving from a topic that contains 271 total messages the stream also contains 271 total messages, but when i create a other stream from that previous stream to flatten it, i get total messages of 542=(271*2). this is the stream deriving from the topic Name : TRANSACTIONSPURE Type : STREAM Key field : Key format : STRING Timestamp field : Not set - using <ROWTIME> Value format : JSON Kafka topic : mongo_conn.digi.transactions (partitions: 1, replication: 1) Field | Type

Is it possible to use multiple left join in Confluent KSQL query? tried to join stream with more than 1 tables , if not then whats the solution?

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Is KSQL making remote requests under the hood, or is a Table actually a global KTable?

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问题 I have a Kafka topic containing customer records, called "customer-created". Each customer is a new record in the topic. There are 4 partitions. I have two ksql-server instances running, based on the docker image confluentinc/cp-ksql-server:5.3.0 . Both use the same KSQL Service Id. I've created a table: CREATE TABLE t_customer (id VARCHAR, firstname VARCHAR, lastname VARCHAR) WITH (KAFKA_TOPIC = 'customer-created', VALUE_FORMAT='JSON', KEY = 'id'); I'm new to KSQL, but my understanding was

KSQL Server Elastic Scaling in Kubernetes

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问题 in the context of kubernetes or else, does it make sense to have one KSQL SERVER per application? When i read the capacity planning for KSQL Server, it is seems the basic settings are for running multiple queries on one server. However I feel like to have a better control over scaling up and down with Kubernetes, it would make more sense to fix the number of Thread by per query, and launch a server configured in kube with let say 1 cpu, where only one application would run. However i am not

KSQL - calculate distance from 2 messages using GEO_DISTANCE

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问题 I've a kafka topic and each message in the topic has lat/lon and event timestamp. Created a stream referring to topic and would like to calculate distance between 2 point using geo_distance . example GpsDateTime lat lon 2016-11-30 22:38:36, 32.685757, -96.735942 2016-11-30 22:39:07, 32.687347, -96.732841 2016-11-30 22:39:37, 32.68805, -96.729726 I would like to create a new stream on the above stream and enrich it with distance. GpsDateTime lat lon Distance 2016-11-30 22:38:36, 32.685757, -96

Ksql: Left Join Displays columns from stream but not tables

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问题 I have one steam and a table in KSQL as mentioned below: Stream name: DEAL_STREAM Table name: EXPENSE_TABLE When I run the below queries it displays only columns from the stream but no table columns are being displays. Is this the expected output. If not am I doing something wrong? SELECT TD.EXPENSE_CODE, TD.BRANCH_CODE, TE.EXPENSE_DESC FROM DEAL_STREAM TD LEFT JOIN EXPENSE_TABLE TE ON TD.EXPENSE_CODE = TE.EXPENSE_CODE WHERE TD.EXPENSE_CODE LIKE '%NL%' AND TD.BRANCH_CODE LIKE '%AM%'; An

null ROWKEY in a stream causes NullPointerException in KSQL join statement

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问题 I have created a stream from a kafka topic which has the following structure: ksql> describe trans_live2; Field | Type ----------------------------------------- ROWTIME | BIGINT (system) ROWKEY | VARCHAR(STRING) (system) ID | INTEGER DESCRIPTION | VARCHAR(STRING) AMOUNT | DOUBLE CURRENCYID | INTEGER ----------------------------------------- When a new row is added to a MySQL table, the source connector sends that row in Apache Kafka which in turn is being streamed in trans_live2 . For example

KSQL介绍：面向Apache Kafka的开源Streaming SQL引擎

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【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> 我非常高兴地宣布KSQL，这是面向Apache Kafka 的一种数据流SQL引擎。KSQL降低了数据流处理这个领域的准入门槛，为使用 Kafka 处理数据提供了一种简单的、完全交互的SQL界面。你不再需要用Java或Python之类的编程语言编写代码了！KSQL具有这些特点：开源（采用Apache 2.0许可证）、分布式、可扩展、可靠、实时。它支持众多功能强大的数据流处理操作，包括聚合、连接、加窗（windowing）和sessionization（捕获单一访问者的网站会话时间范围内所有的点击流事件）等等。文章目录 1 一个简单的例子 2 查询流式数据意味着什么？这与SQL数据库相比怎样？ 3 KSQL适用于什么？ 3.1 1、实时监控遇上实时分析 3.2 2、安全和异常检测 3.3 3、联机数据整合 3.4 4、应用程序开发 4 KSQL中的核心抽象 5 KSQL实战：实时点击流分析和异常检测 6 内部结构 7 Kafka + KSQL颠覆数据库 8 KSQL的下一站是什么？ 9 如何获取KSQL？一个简单的例子如果想及时了解Spark、Hadoop或者Hbase相关的文章，欢迎关注微信公共帐号： iteblog_hadoop 查询流式数据意味着什么？这与SQL数据库相比怎样？

Kafka 流数据 SQL 引擎 -- KSQL

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【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> KSQL 是什么？ KSQL 是一个 Kafka 的 SQL 引擎，可以让我们在流数据上持续执行 SQL 查询例如，有一个用户点击流的topic，和一个可持续更新的用户信息表，使用 KSQL 对点击流数据、用户表进行建模，并把二者连接起来，之后 KSQL 会持续查询这个topic的数据流，并放入表中 KSQL 是开源的、分布式的，具有高可靠、可扩展、实时的特性 KSQL 支持强大的流处理操作，包括聚合、连接、窗口、会话等等 KSQL 解决了什么问题？ KSQL 的主要目的是为了降低流处理的操作门槛，为 Kafka 提供了简单而完善的 SQL 交互接口之前，为了使用流处理引擎，需要熟悉一些开发语言，例如 Java, C#, Python，Kafka 的流处理引擎作为 Kafka 项目的一部分，是一个 Java 库，需要使用者有熟练的 Java 技能相对的，KSQL 只需要使用者熟悉 SQL 即可，这使得 Kafka Stream 能够进入更广阔的应用领域，例如商业分析，熟悉 SQL 的分析人员就可以操作，而不用一定是开发人员 KSQL 的应用场景有哪些？ 1. 实时监控实时分析 CREATE TABLE error_counts AS SELECT error_code, count(*)FROM

Get Latest value from Kafka

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问题 I have a Kafka topic called A . format of data in topic A is : { id : 1, name:stackoverflow, created_at:2017-09-28 22:30:00.000} { id : 2, name:confluent, created_at:2017-09-28 22:00:00.000} { id : 3, name:kafka, created_at:2017-09-28 24:42:00.000} { id : 4, name:apache, created_at:2017-09-28 24:41:00.000} Now in consumer side i want to get only latest data of one hour window means every one hour i need to get latest value from topic based on created_at My expected output is : { id : 1, name

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