Flink practical problems (VII): no watermark (watermarks are only available eventtime is used)

When implementing window statistics , appear No Watermark(Watermarks are only available EventTime is used)

Problem analysis ：

When we push data , Consumption data available , But it's always suggested that No Watermark, Find the official website documentation ：

    Flink about Kafka Support sending partition by partition watermark.Watermark stay Kafka consumer In the middle of . By zone watermark The merging method and in stream shuffle Time merging Watermark In the same way . Source Output watermark The smallest partition read by watermark decision . If topic Some partitions in are idle ,watermark The generator will not advance . You can set... In the table configuration  'table.exec.source.idle-timeout'  Option to avoid the above problems

stay StreamTableEnvironment Set up table.exec.source.idle-timeout Parameters can be displayed normally