8.226 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
CON_ID	NUMBER	The ID of the container to which the data pertains. Possible values include: 0: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs. 1: This value is used for rows containing data that pertain to only the root n: Where n is the applicable container ID for the rows containing data