# QueryStatistics
<a name="API_QueryStatistics"></a>

Contains the number of log events scanned by the query, the number of log events that matched the query criteria, and the total number of bytes in the log events that were scanned.

If the query involved log groups that have field index policies, the estimated number of skipped log events and the total bytes of those skipped log events are included. Using field indexes to skip log events in queries reduces scan volume and improves performance. For more information, see [Create field indexes to improve query performance and reduce scan volume](https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/CloudWatchLogs-Field-Indexing.html).

## Contents
<a name="API_QueryStatistics_Contents"></a>

 ** bytesScanned **   <a name="CWL-Type-QueryStatistics-bytesScanned"></a>
The total number of bytes in the log events scanned during the query.  
Type: Double  
Required: No

 ** estimatedBytesSkipped **   <a name="CWL-Type-QueryStatistics-estimatedBytesSkipped"></a>
An estimate of the number of bytes in the log events that were skipped when processing this query, because the query contained an indexed field. Skipping these entries lowers query costs and improves the query performance time. For more information about field indexes, see [PutIndexPolicy](https://docs.aws.amazon.com/AmazonCloudWatchLogs/latest/APIReference/API_PutIndexPolicy.html).  
Type: Double  
Required: No

 ** estimatedRecordsSkipped **   <a name="CWL-Type-QueryStatistics-estimatedRecordsSkipped"></a>
An estimate of the number of log events that were skipped when processing this query, because the query contained an indexed field. Skipping these entries lowers query costs and improves the query performance time. For more information about field indexes, see [PutIndexPolicy](https://docs.aws.amazon.com/AmazonCloudWatchLogs/latest/APIReference/API_PutIndexPolicy.html).  
Type: Double  
Required: No

 ** logGroupsScanned **   <a name="CWL-Type-QueryStatistics-logGroupsScanned"></a>
The number of log groups that were scanned by this query.  
Type: Double  
Required: No

 ** recordsMatched **   <a name="CWL-Type-QueryStatistics-recordsMatched"></a>
The number of log events that matched the query string.  
Type: Double  
Required: No

 ** recordsScanned **   <a name="CWL-Type-QueryStatistics-recordsScanned"></a>
The total number of log events scanned during the query.  
Type: Double  
Required: No

## See Also
<a name="API_QueryStatistics_SeeAlso"></a>

For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/logs-2014-03-28/QueryStatistics) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/logs-2014-03-28/QueryStatistics) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/logs-2014-03-28/QueryStatistics)