V$FILE_HISTOGRAM

V$FILE_HISTOGRAM displays a histogram of all synchronous single block reads on a per-file basis (for data files). The histogram has buckets of time intervals from < 1 ms, < 2 ms, < 4 ms, < 8 ms, ... < 2²¹ ms, < 2²² ms, and >= 2²² ms.

The histogram will not be filled unless the STATISTICS_LEVEL initialization parameter is set to ALL.

Column	Datatype	Description
`FILE#`	`NUMBER`	File number
`SINGLEBLKRDTIM_MILLI`	`NUMBER`	Amount of time the bucket represents (in milliseconds). If the duration = `num`, then this column represents waits of duration < `num` that are not included in any smaller bucket.
`SINGLEBLKRDS`	`NUMBER`	Number of waits of the duration belonging to the bucket of the histogram