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.