AWS Kinesis Analytics支持除ROWTIME之外的水印和滑动窗口机制。以下是一个使用Kinesis Data Analytics for SQL的示例:
CREATE OR REPLACE STREAM "SOURCE_SQL_STREAM" (
"SENSOR_ID" VARCHAR(16),
"TEMPERATURE" DOUBLE,
"EVENT_TIME" TIMESTAMP
);
CREATE OR REPLACE PUMP "STREAM_PUMP" AS INSERT INTO "SOURCE_SQL_STREAM"
SELECT "SENSOR_ID", "TEMPERATURE", "EVENT_TIME" FROM "SOURCE_SQL_STREAM_001";
CREATE OR REPLACE STREAM "DESTINATION_SQL_STREAM" (
"SENSOR_ID" VARCHAR(16),
"AVG_TEMPERATURE" DOUBLE,
"WINDOW_START" TIMESTAMP,
"WINDOW_END" TIMESTAMP
);
CREATE OR REPLACE PUMP "STREAM_PUMP" AS INSERT INTO "DESTINATION_SQL_STREAM"
SELECT "SENSOR_ID", AVG("TEMPERATURE"), TUMBLE_START("EVENT_TIME", INTERVAL '1' MINUTE) AS "WINDOW_START", TUMBLE_END("EVENT_TIME", INTERVAL '1' MINUTE) AS "WINDOW_END"
FROM "SOURCE_SQL_STREAM"
GROUP BY "SENSOR_ID", TUMBLE("EVENT_TIME", INTERVAL '1' MINUTE);
-- 设置水印延迟时间为10秒
ALTER STREAM "DESTINATION_SQL_STREAM" SET WATERMARK "EVENT_TIME" = "EVENT_TIME" - INTERVAL '10' SECOND;
在这个示例中,源流中的数据流包含SENSOR_ID(传感器ID)、TEMPERATURE(温度)和EVENT_TIME(事件时间)字段。我们使用滑动窗口函数TUMBLE_START和TUMBLE_END来计算每个传感器在每个滑动窗口期间的平均温度,并将结果插入到目标流中。还使用ALTER STREAM语句将水印延迟设置为10秒。
请注意,这只是一个示例,您可以根据自己的需求修改SQL查询和设置水印延迟时间。