Indexes

Scenarios

The system collects the number of missing indexes, missing indexes in user seeks, and index usage of your DB instance to help you troubleshoot performance problems.

Missing Indexes

1. Click in the upper left corner and select a region.
2. Click in the upper left corner of the page and choose Databases > Relational Database Service.
3. On the Instances page, click the instance name to go to the Overview page.
4. In the navigation pane, choose Indexes under DBA Assistant.
5. On the displayed page, enable Collect Statistics.

   Collecting statistics takes a little time. Wait about 10 minutes or so and then refresh the page to view the latest data.

   • Statistics

     Table 1 Statistical items

     Item	Description
     Missing Indexes	Total number of missing indexes in all tables of the instance and the number of missing indexes that can improve the performance by more than 80%.
     Missing Indexes in User Seeks	Numbers of missing indexes in user seeks in the last 1 day, 1 week, 2 weeks, and 1 month, and the percentage of each number to the total missing indexes

   • Analysis

     Table 2 Item description

     Item	Description
     Missing Indexes over the Last 24 Hours	Changes in the number of missing indexes in the last 24 hours
     Last User Seek Time	Numbers of missing indexes in user seeks in the last 1 day, 1 week, 2 weeks, and 1 month
     Avg. User Query Cost	Average query cost reduction resulting from missing indexes
     Avg. Performance Improvement	Average performance improvement resulting from missing indexes

   • Details

     You can export table data and missing index statements.

Index Usage

1. Click in the upper left corner and select a region.
2. Click in the upper left corner of the page and choose Databases > Relational Database Service.
3. On the Instances page, click the instance name to go to the Overview page.
4. In the navigation pane, choose Indexes under DBA Assistant.
5. On the Index Usage page, enable Collect Statistics.

   Collecting statistics takes a little time. Wait about 10 minutes or so and then refresh the page to view the latest data.

   • Statistics

     Table 3 Statistical items

     Item	Description
     Total (MB)	Total space occupied by all indexes in the instance
     Total	Total number of indexes in the instance
     Fragmentation > 80%	Number of indexes whose fragmentation rate is greater than 80%
     User seeks < 100	Number of indexes that are sought less than 100 times

   • Analysis

     Table 4 Item description

     Item	Description
     Fragmentation	Fragmentation rates of all indexes in the instance
     Usage	Usage of all indexes in the instance
     Top Fragmentation	Top 10 fragmentation rates of clustered and nonclustered indexes
     Size	Changes in the total space occupied by all indexes in the instance

   • Index Usage Details

     You can export index usage details to an Excel file.