动态表刷新跳过或失败故障排除

This topic helps you troubleshoot skipped or failed refreshes. For slow refresh diagnostics, see Monitor dynamic table performance.

When monitoring your dynamic table refreshes, note the following:

• If you see many SKIPPED entries, see 跳过刷新.
• If you see consistent FAILED entries, see 刷新失败.
• If you see a SCHEDULED or EXECUTING entry stuck for a long time, see Monitor dynamic table performance.

跳过刷新

动态表按时间表刷新。计划刷新开始时，以下情况可能会导致跳过刷新：

• 如果正在刷新的动态表上游有另一个动态表，而上游的刷新失败或被跳过。
• 如果动态表的上一个刷新仍在运行。
• If the dynamic table’s refresh often takes longer than the target lag or there’s a significant difference between the target and actual lag, Snowflake might skip a refresh to reduce the rate of future skips.

例如，如果动态表的目标滞后为 1 分钟，但通常需要一小时才能刷新，则系统会相应地调整“实际滞后”。

To improve refresh performance, see Optimize dynamic table performance.

手动刷新永远不会跳过，但可能会导致跳过其他计划的刷新，特别是在对动态表执行频繁的手动刷新时。这样做会阻止下游动态表刷新。因此，如果某动态表具有根据目标延迟进行刷新的下游动态表，Snowflake 建议您避免频繁地对该动态表执行手动刷新。

刷新失败

刷新失败通常是由于动态表的查询定义问题、输入数据（例如，解析错误）或上游失败问题造成的。

查找失败的刷新

要查找失败的刷新，请查询刷新历史记录：

SELECT
  name,
  data_timestamp,
  state,
  state_code,
  state_message
FROM TABLE(INFORMATION_SCHEMA.DYNAMIC_TABLE_REFRESH_HISTORY(
  NAME_PREFIX => 'MY_DB.MY_SCHEMA',
  ERROR_ONLY => TRUE
));

You can also use the Refresh History page in Snowsight to view failed refreshes. The Source Data Timestamp column shows the time of the last successful refresh. A failed refresh doesn’t advance this value. If it’s far behind the target lag, your dynamic table is lagging.

诊断刷新的失败

Use the Query Profile to troubleshoot by selecting Show query profile next to each refresh. This shows the execution graph of the query.

Use the Graph view in Snowsight to visualize dependencies. A failed or suspended upstream dynamic table causes its downstream tables to fail. For more information, see View the graph of tables connected to your dynamic tables.

查询事件表以查找故障

您可以查询事件表以查找动态表中的刷新失败：

SELECT
  timestamp,
  resource_attributes:"snow.executable.name"::VARCHAR AS dt_name,
  resource_attributes:"snow.query.id"::VARCHAR AS query_id,
  value:message::VARCHAR AS error
FROM my_event_table
WHERE
  resource_attributes:"snow.executable.type" = 'DYNAMIC_TABLE' AND
  resource_attributes:"snow.database.name" = 'MY_DB' AND
  value:state = 'FAILED'
ORDER BY timestamp DESC;

For more information about configuring event tables and setting up alerts, see Event table monitoring and alerts for dynamic tables.