onstat -g rah command: Section 3 Active Read Ahead Daemons
This section displays volatile information about read ahead requests currently being processed.
Figure 3. onstat -g rah command output, section 3
Active Read Ahead Daemons
rstcb ra_req Req ID Req Type Req State Partnum Read Threshold Ahead
0x44d4a408 0x55317d40 47 DATA ACTIVE 1001a2 456 500 1000
Output description
- rstcb
- The rstcb address of the RA daemon.
- ra_req
- The memory address of the read-ahead request structure.
- Req ID
- A number uniquely identifying a particular request.
- Req Type
-
The operation type of the request. Possible values:
- DATA
- LEAF
- IDX/DAT
- PAGELIST
- ROLLBACK
- LASTCOMMIT
- Req State
- All possible request states:
- PENDING
- FREE
- ACTIVE
- DONE
- RESCHED
- Partnum
- The partition number of the table or index being read.
- Read
- The number of requested pages processed so far by the reader. Another way to think of this value is as the ‘position’ of the reader with respect to its request.
- Threshold
- When ‘read’ above catches up to this threshold, the daemon will continue reading ahead on behalf of this request.
- Ahead
- The total number of pages that have been read ahead on behalf of this request. The difference between this value and ‘read’ indicates how far the daemon is ahead of the reader.