Manage Usage Limits Query Limits and Other Administrative Tasks#

Keywords: AWS, Amazon, Redshift, Serverless, sls.


作为一款商用的数据仓库产品, redshift 增加了很多对服务器资源的使用进行细致化管理的功能. 并且把很多监控面板都集成到了 console 中.

Manage Redshift processing units (RPU) Limit for Workgroup#

你可以为每个 workgroup 设置最多 4 个 limit rule. 所谓 limit rule 就是说在多长时间内, 最多用多少 RPU / Hour, 如果超了, 要采取什么 action.

Frequency (多长时间内) 的选项有:

  • Daily

  • Weekly

  • Monthly

Action 的选项有:

  • Alert: 发 notification, 你自己选择 SNS topic

  • Log to System Table: 记录到 Redshift system table 中

  • Turn off User Query: 杀掉新的 query, 这也会发送 notification 到 SNS topic

例如你可以说你的 workgroup 有 8 个 RPU, 最大能 scale 到 32 个. 每天最多用 32 个 RPU. 也就是以 8 个 RPU 的状态跑 4 小时.

Manager Redshift Query Limit for Workgroup#

你还可以为每个 workgroup 中的 query 配置 Limit. 允许设置 limit 的 metrics 如下:

  • Query execution time: Elapsed execution time for a query, in seconds. Execution time doesn’t include time spent waiting in a queue. If a query exceeds the set execution time, Amazon Redshift Serverless stops the query. Valid values are 0-86399

  • Query queue time: Time spent waiting in a queue, in seconds. Valid values are 0-86399

  • Query CPU time: CPU time used by the query, in seconds. CPU time is distinct from Query execution time. Valid values are 0-999999

  • Query CPU usage: Percent of CPU capacity used by the query. Valid values are 0-6399 (63.99%)

  • Scan row count: The number of rows in a scan step. The row count is the total number of rows emitted before filtering rows marked for deletion (ghost rows) and before applying user-defined query filters. Valid values are 0-999,999,999,999,999

  • Return rows count: The number of rows returned by the query. Valid values are 0-999999999999999

  • Rows joined: The number of rows processed in a join step. Valid values are 0-999,999,999,999,999

  • Nested loop join row count: The number or rows in a nested loop join. Valid values are 0-999999999999999

  • Blocks read: Number of 1 MB data blocks read by the query. Valid values are 0-1048575

  • Memory to disk: Temporary disk space used to write intermediate results, in 1 MB blocks. Valid values are 0-319815679

Filtering queries#

你可以在 AWS Redshift Console 界面的 Query and database monitoring 中查看你执行过的 query 的详细信息, 包括 SQL statement, 耗时, query plan, related metrics, 非常详细.

Checking Amazon Redshift Serverless summary data using the dashboard#

你可以在 AWS Redshift Console 界面的 Redshift Serverless Dashboard 上看到很多监控信息, 包括:

  • Queries metrics

  • RPU capacity used

  • Alarms


以前的 Redshift Cluster 模式下的 workload management (WLM) 分的组在 Redshift serverless 中就对应着不同的 WorkGroup. 例如你以前有一些可预估的定时 Query, 例如每小时跑一次的报表. 那么你可以将其放在一个 Group 里给与一个在预计内的上限. 而对于探索性的开发者, 你可以将其放到另一个 Group 里, 并给他们比较高的上限以应对复杂的工作. 同时设置 RPU Rule 来限制特别夸张的 Query, 例如运行时间特别长, 扫描数据特别多, 例如全表扫描. 从而避免高额账单.