The host from which the client connected. Rows for which the HOST  column in the underlying Performance Schema table is NULL  are assumed to be for background threads and are reported with a host name of background . 

• event_name 

The file I/O event name. 

• total 

The total number of occurrences of the file I/O event for the host. 

• total_latency 

The total wait time of timed occurrences of the file I/O event for the host. 

• max_latency 

The maximum single wait time of timed occurrences of the file I/O event for the host. 

## 28.4.3.4 The host_summary_by_stages and x$host_summary_by_stages Views 

These views summarize statement stages, grouped by host. By default, rows are sorted by host and descending total latency. 

The host_summary_by_stages  and x$host_summary_by_stages  views have these columns: 

• host 

The host from which the client connected. Rows for which the HOST  column in the underlying Performance Schema table is NULL  are assumed to be for background threads and are reported with a host name of background . 

## 28.4.3.5 The host_summary_by_statement_latency and x $host_summary_by_statement_latency Views 

• event_name 

The stage event name. 

• total 

The total number of occurrences of the stage event for the host. 

• total_latency 

The total wait time of timed occurrences of the stage event for the host. 

• avg_latency 

The average wait time per timed occurrence of the stage event for the host. 

These views summarize overall statement statistics, grouped by host. By default, rows are sorted by descending total latency. 

The host_summary_by_statement_latency  and x$host_summary_by_statement_latency views have these columns: 

