What should you do?

Your customer has a global chat application that uses a multi-regional Cloud Spanner instance. The application has recently experienced degraded performance after a new version of the application was launched. Your customer asked you for assistance. During initial troubleshooting, you observed high read latency.

What should you do?
A . Use query parameters to speed up frequently executed queries.
B . Change the Cloud Spanner configuration from multi-region to single region.
C . Use SQL statements to analyze SPANNER_SYS.READ_STATS* tables.
D . Use SQL statements to analyze SPANNER_SYS.QUERY_STATS* tables.

Answer: C

Explanation:

To troubleshoot high read latency, you can use SQL statements to analyze the SPANNER_SYS.READ_STATS* tables. These tables contain statistics about read operations in Cloud Spanner, including the number of reads, read latency, and the number of read errors. By analyzing these tables, you can identify the cause of the high read latency and take appropriate action to resolve the issue. Other options, such as using query parameters to speed up frequently executed queries or changing the Cloud Spanner configuration from multi-region to single region, may not be directly related to the issue of high read latency. Similarly, analyzing the SPANNER_SYS.QUERY_STATS* tables, which contain statistics about query operations, may not be relevant to the issue of high read latency.