Re: sbt system events

From: john <orclwzrd_at_yahoo.com>
Date: 29 May 2003 06:44:08 -0700
Message-ID: <4e062d34.0305290544.72dc8915@posting.google.com>

Further research yesterday led me to the following:

Here is the wizardly stuff I just found in the 9.2 RMAN users guide, Chapter 15.
This is all I can find so far. My interpretation of this is that the sbt events are idle as far as performance indicators go.

Monitoring RMAN Interaction with the Media Manager You can use the event names in the dynamic performance event views to monitor RMAN calls to the media management API. The event names have one-to-one correspondence with sbt functions, as shown in the following examples:

sbtinit
sbtopen
sbtread
sbtwrite
sbtbackup

Before making a call to any of functions in the media management API, the server adds a row in V$SESSION_WAIT, with the STATUS column including the string WAIT. The V$SESSION_WAIT.SECONDS_IN_WAIT column shows the number of seconds that the server has been waiting for this call to return. After an sbt function is returned from the media manager, this row disappears.

A row in V$SESSION_WAIT corresponding to an sbt event name does not indicate a problem, because the server updates these rows at runtime. The rows appear and disappear as calls are made and returned. However, if the SECONDS_IN_WAIT column is high, then the media manager may be hung.

To monitor the sbt events, you can run the following SQL query:

COLUMN EVENT FORMAT a10
COLUMN SECONDS_IN_WAIT FORMAT 999
COLUMN STATE FORMAT a20
COLUMN CLIENT_INFO FORMAT a30

SELECT p.SPID, EVENT, SECONDS_IN_WAIT AS SEC_WAIT,

STATE, CLIENT_INFO
FROM V$SESSION_WAIT sw, V$SESSION s, V$PROCESS p WHERE sw.EVENT LIKE 'sbt%'

       AND s.SID=sw.SID
       AND s.PADDR=p.ADDR

Examine the SQL output to determine which sbt functions are waiting. For example, the following output indicates that RMAN has been waiting for the sbtbackup function to return for ten minutes:

SPID EVENT        SEC_WAIT STATE                CLIENT_INFO
---- ---------- ---------- --------------------
------------------------------
8642 sbtbackup         600 WAITING              rman

channel=ORA_SBT_TAPE_1

Brian Peasland <oracle_dba_at_remove_spam.peasland.com> wrote in message news:<3ED507C0.7C8F0FEB_at_remove_spam.peasland.com>...
> "sbt" typically means Streaming Backup Tape. I get these events in my
> databases that use RMAN to backup to a tape device. The events should be
> pretty self explanatory. For instnace, "sbtwrite" is waiting on a write
> event on the sbt device.
>
> HTH,
> Brian
>
Received on Thu May 29 2003 - 08:44:08 CDT