Viewing column statistics
After generating the statistics successfully, Data Catalog stores this information for the cost-based optimizers in Amazon Athena and Amazon Redshift to make optimal choices when running queries. The statistics varies based on the type of the column.
- AWS Management Console
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To view column statistics for a table
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After running column statistics task, the Column statistics tab on the Table details page shows the statistics for the table.
The following statistics are available:
Column name: Column name used to generate statistics
Last updated: Data and time when the statistics were generated
Average length: Average length of values in the column
Distinct values: Total number of distinct values in the column. We estimate the number of distinct values in a column with 5% relative error.
Max value: The largest value in the column.
Min value: The smallest value in the column.
Max length: The length of the highest value in the column.
Null values: The total number of null values in the column.
True values: The total number of true values in the column.
False values: The total number of false values in the column.
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numFiles: The total number of files in the table. This value is available under the Advanced properties tab.
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- AWS CLI
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The following example shows how to retrieve column statistics using AWS CLI.
aws glue get-column-statistics-for-table \ --database-name<test_db>\ --table-name<test_tble>\ --column-names<col1>You can also view the column statistics using the GetColumnStatisticsForTable API operation.
