Examine the following information from the AWR report:
Top 5 Timed Events
~~~~~~~~~~~~~~~~~~ % Total
Event Waits Time (s) Call Time
————————————– ———— ———– ———
CPU time 559 88.80
log file parallel write 2.181 28 4.42
SQL*Net more data from client 516.611 27 4.24
db file parallel write 13.383 13 2.04
db file sequential read 563 2 .27
Which could cause waits on the db file sequential read event?
A.
too many full table scans
B.
too large a database buffer cache
C.
too many waits occurring while reading multiple blocks synchronously
D.
too many index range scans occurring which refers to blocks not in the database buffer cache
I think A is correct
Rarely, full table scan calls could get truncated to a single block call because of extent boundaries, or buffers present in the buffer cache. These waits would also show up as db file sequential read.