Question

步骤1：运行生产者以创建样本数据

./bin/kafka-avro-console-producer \
         --broker-list localhost:9092 --topic stream-test-topic \
         --property schema.registry.url=http://localhost:8081 \
         --property value.schema='{"type":"record","name":"dealRecord","fields":[{"name":"DEAL_ID","type":"string"},{"name":"DEAL_EXPENSE_CODE","type":"string"},{"name":"DEAL_BRANCH","type":"string"}]}'

示例数据：

{"DEAL_ID":"deal002", "DEAL_EXPENSE_CODE":"EXP002", "DEAL_BRANCH":"AMSTERDAM"}
{"DEAL_ID":"deal003", "DEAL_EXPENSE_CODE":"EXP003", "DEAL_BRANCH":"AMSTERDAM"}
{"DEAL_ID":"deal004", "DEAL_EXPENSE_CODE":"EXP004", "DEAL_BRANCH":"AMSTERDAM"}
{"DEAL_ID":"deal005", "DEAL_EXPENSE_CODE":"EXP005", "DEAL_BRANCH":"AMSTERDAM"}
{"DEAL_ID":"deal006", "DEAL_EXPENSE_CODE":"EXP006", "DEAL_BRANCH":"AMSTERDAM"}
{"DEAL_ID":"deal007", "DEAL_EXPENSE_CODE":"EXP001", "DEAL_BRANCH":"AMSTERDAM"}
{"DEAL_ID":"deal008", "DEAL_EXPENSE_CODE":"EXP002", "DEAL_BRANCH":"AMSTERDAM"}
{"DEAL_ID":"deal009", "DEAL_EXPENSE_CODE":"EXP003", "DEAL_BRANCH":"AMSTERDAM"}
{"DEAL_ID":"deal010", "DEAL_EXPENSE_CODE":"EXP004", "DEAL_BRANCH":"AMSTERDAM"}
{"DEAL_ID":"deal011", "DEAL_EXPENSE_CODE":"EXP005", "DEAL_BRANCH":"AMSTERDAM"}
{"DEAL_ID":"deal012", "DEAL_EXPENSE_CODE":"EXP006", "DEAL_BRANCH":"AMSTERDAM"}

步骤2：打开另一个终端并运行使用者以测试数据。

./bin/kafka-avro-console-consumer --topic stream-test-topic \
         --bootstrap-server localhost:9092 \
         --property schema.registry.url=http://localhost:8081 \
         --from-beginning

步骤3：打开另一个终端并运行生产者。

./bin/kafka-avro-console-producer \
         --broker-list localhost:9092 --topic expense-test-topic \
--property "parse.key=true" \
--property "key.separator=:" \
--property schema.registry.url=http://localhost:8081 \
--property key.schema='"string"' \
         --property value.schema='{"type":"record","name":"dealRecord","fields":[{"name":"EXPENSE_CODE","type":"string"},{"name":"EXPENSE_DESC","type":"string"}]}'

数据：

"pk1":{"EXPENSE_CODE":"EXP001", "EXPENSE_DESC":"Regulatory Deposit"}
"pk2":{"EXPENSE_CODE":"EXP002", "EXPENSE_DESC":"ABC - Sofia"}
"pk3":{"EXPENSE_CODE":"EXP003", "EXPENSE_DESC":"Apple Corporation"}
"pk4":{"EXPENSE_CODE":"EXP004", "EXPENSE_DESC":"Confluent Europe"}
"pk5":{"EXPENSE_CODE":"EXP005", "EXPENSE_DESC":"Air India"}
"pk6":{"EXPENSE_CODE":"EXP006", "EXPENSE_DESC":"KLM International"}

步骤4：打开另一个终端并运行消费者

./bin/kafka-avro-console-consumer --topic expense-test-topic \
         --bootstrap-server localhost:9092 \
--property "parse.key=true" \
--property "key.separator=:" \
--property schema.registry.url=http://localhost:8081 \
         --from-beginning

第5步：登录KSQL客户端。

./bin/ksql http://localhost:8088

创建以下流和表并运行连接查询。

KSQL：

STREAM：

    CREATE STREAM SAMPLE_STREAM 
       (DEAL_ID VARCHAR, DEAL_EXPENSE_CODE varchar, DEAL_BRANCH VARCHAR) 
       WITH (kafka_topic='stream-test-topic',value_format='AVRO', key = 'DEAL_ID');

TABLE：

CREATE TABLE SAMPLE_TABLE 
   (EXPENSE_CODE varchar, EXPENSE_DESC VARCHAR)
   WITH (kafka_topic='expense-test-topic',value_format='AVRO', key = 'EXPENSE_CODE');

以下是OUTPUT：

ksql> SELECT STREAM1.DEAL_EXPENSE_CODE, TABLE1.EXPENSE_DESC 
       from SAMPLE_STREAM STREAM1 LEFT JOIN SAMPLE_TABLE TABLE1 
       ON STREAM1.DEAL_EXPENSE_CODE = TABLE1.EXPENSE_CODE  
       WINDOW TUMBLING (SIZE 3 MINUTE) 
       GROUP BY STREAM1.DEAL_EXPENSE_CODE, TABLE1.EXPENSE_DESC;

EXP001 | null
EXP001 | null
EXP002 | null
EXP003 | null
EXP004 | null
EXP005 | null
EXP006 | null
EXP002 | null
EXP002 | null

Answer 1

tl; dr：您的表数据需要键入您要加入的列。

使用上面的示例数据，这里有如何调查和修复。

使用KSQL检查主题中的数据（不需要kafka-avro-console-consumer）。输出数据的格式为时间戳，键，值

stream：

ksql> print 'stream-test-topic' from beginning;
Format:AVRO
30/04/18 15:59:13 BST, null, {"DEAL_ID": "deal002", "DEAL_EXPENSE_CODE": "EXP002", "DEAL_BRANCH": "AMSTERDAM"}
30/04/18 15:59:13 BST, null, {"DEAL_ID": "deal003", "DEAL_EXPENSE_CODE": "EXP003", "DEAL_BRANCH": "AMSTERDAM"}
30/04/18 15:59:13 BST, null, {"DEAL_ID": "deal004", "DEAL_EXPENSE_CODE": "EXP004", "DEAL_BRANCH": "AMSTERDAM"}

table：

ksql> print 'expense-test-topic' from beginning;
Format:AVRO
30/04/18 16:10:52 BST, pk1, {"EXPENSE_CODE": "EXP001", "EXPENSE_DESC": "Regulatory Deposit"}
30/04/18 16:10:52 BST, pk2, {"EXPENSE_CODE": "EXP002", "EXPENSE_DESC": "ABC - Sofia"}
30/04/18 16:10:52 BST, pk3, {"EXPENSE_CODE": "EXP003", "EXPENSE_DESC": "Apple Corporation"}
30/04/18 16:10:52 BST, pk4, {"EXPENSE_CODE": "EXP004", "EXPENSE_DESC": "Confluent Europe"}
30/04/18 16:10:52 BST, pk5, {"EXPENSE_CODE": "EXP005", "EXPENSE_DESC": "Air India"}
30/04/18 16:10:52 BST, pk6, {"EXPENSE_CODE": "EXP006", "EXPENSE_DESC": "KLM International"}

此时，请注意密钥（pk<x>）与我们将加入的列不匹配

注册两个主题：

ksql> CREATE STREAM deals WITH (KAFKA_TOPIC='stream-test-topic', VALUE_FORMAT='AVRO');

 Message
----------------
 Stream created
----------------

ksql> CREATE TABLE expense_codes_table WITH (KAFKA_TOPIC='expense-test-topic', VALUE_FORMAT='AVRO', KEY='EXPENSE_CODE');

 Message
---------------
 Table created
---------------

告诉KSQL从每个主题的开头查询事件

ksql> SET 'auto.offset.reset' = 'earliest';
Successfully changed local property 'auto.offset.reset' from 'null' to 'earliest'

验证每个DDL（KEY='EXPENSE_CODE'）的表声明密钥是否与基础Kafka消息的实际密钥匹配（可通过ROWKEY系统列获得）：
```
ksql> SELECT ROWKEY, EXPENSE_CODE FROM expense_codes_table;
pk1 | EXP001
pk2 | EXP002
pk3 | EXP003
pk4 | EXP004
pk5 | EXP005
pk6 | EXP006
```
密钥不匹配。我们的加入注定要失败！

魔术解决方法 - 让我们使用KSQL重新设置主题！

将表格的源主题注册为KSQL STREAM ：

ksql> CREATE STREAM expense_codes_stream WITH (KAFKA_TOPIC='expense-test-topic', VALUE_FORMAT='AVRO');

 Message
----------------
 Stream created
----------------

创建一个派生流，键入正确的列。这是一个重新加入Kafka主题的基础。

ksql> CREATE STREAM EXPENSE_CODES_REKEY AS SELECT * FROM expense_codes_stream PARTITION BY EXPENSE_CODE;

 Message
----------------------------
 Stream created and running
----------------------------

在重新键入的主题之上重新注册KSQL _TABLE_：

ksql> DROP TABLE expense_codes_table;

 Message
----------------------------------------
 Source EXPENSE_CODES_TABLE was dropped
----------------------------------------
ksql> CREATE TABLE expense_codes_table WITH (KAFKA_TOPIC='EXPENSE_CODES_REKEY', VALUE_FORMAT='AVRO', KEY='EXPENSE_CODE');

 Message
---------------
 Table created
---------------

检查新表上的键（声明与消息）匹配：

ksql> SELECT ROWKEY, EXPENSE_CODE FROM expense_codes_table;
EXP005 | EXP005
EXP001 | EXP001
EXP002 | EXP002
EXP003 | EXP003
EXP006 | EXP006
EXP004 | EXP004

成功加入：

ksql> SELECT D.DEAL_EXPENSE_CODE, E.EXPENSE_DESC \
FROM deals D \
  LEFT JOIN expense_codes_table E \
  ON D.DEAL_EXPENSE_CODE = E.EXPENSE_CODE  \
WINDOW TUMBLING (SIZE 3 MINUTE) \
GROUP BY D.DEAL_EXPENSE_CODE, E.EXPENSE_DESC;

EXP006 | KLM International
EXP003 | Apple Corporation
EXP002 | ABC - Sofia
EXP004 | Confluent Europe
EXP001 | Regulatory Deposit
EXP005 | Air India

汇编4.1.0 - ＆gt; KSQL：STREAM-TABLE连接 - ＆gt;表数据为null

1 个答案: