Re: Enterprise Manager warns of blocking on LGWR

Check DBA_HIST_ACTIVE_SESS_HISTORY where the time period when the alert was issued where BLOCKING_SESSION_ID is not null - of course, you'll need the SID for the LGWR during that time period to see how many sessions (if any) LGWR was blocking when the alert was issued.

If LGWR SID was blocking you can look at DBA_HIST_ACTIVE_SESS_HISTORY for that SID and see what it was waiting on and causing the sessions to be blocked.

(Of course assuming you have license for Diagnostics or Tuning pack)

Chris

On Thu, Dec 7, 2017 at 2:52 PM, Jeffrey Beckstrom <JBECKSTROM_at_gcrta.org> wrote:

> We are running EM 12.1.0.5. For the past several months, since upgrading
> our agent to 12.1.0.5, across various databases we have been receiving a
> blocking alert warning with the blocker being LGWR. By the time you log on
> the database directly or through Enterprise Manager, no blocking locks can
> be found. In fact, sometimes no active sessions are found or run quickly.
> After about 15+ minutes the alert clears.
>
> We do correctly receive the alert on user sessions that are causing a
> locking condition.
>
> Is there a way to bypass LGWR?
>
> Jeffrey Beckstrom
> Lead Database Administrator
> Information Technology Department
> Greater Cleveland Regional Transit Authority
> 1240 W. 6th Street
> <https://maps.google.com/?q=1240+W.+6th+Street+Cleveland,+Ohio+44113&entry=gmail&source=g>
> Cleveland, Ohio 44113
> <https://maps.google.com/?q=1240+W.+6th+Street+Cleveland,+Ohio+44113&entry=gmail&source=g>
>
>

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