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There is more and more happening in the world of visualization and visualizing Oracle performance specifically with v$active_session_history.

Of these visualizations,  the one pushing the envelope the most is Marcin Przepiorowski. Marcin is responsible for writing S-ASH , ie Simulated ASH versions 2.1,2.2 and 2.3. See

• http://oracleprof.blogspot.com/2011/11/new-release-of-s-ash-v23.html
• https://github.com/pioro/orasash

Here are some examples of what I have seen happening out there in the web with these visualizations grouped by the visualization tool.

I’d be grateful if anyone who is responsible for Oracle database backups could take a quick (3 question) survey on their use or otherwise of the Fast (Flash) Recovery Area feature. http://www.surveymonkey.com/s/J93L7WT All responses are anonymous.

Database is getting high waits on buffer busy waits. Here is an example period where 5 sessions are completely blocked on buffer busy waits for 4 minutes:

  select
       to_char(min(sample_time),'HH24:MI') maxst,
       to_char(max(sample_time),'HH24:MI') minst,
       count(*),
       session_id,
       ash.p1,
       ash.p2,
       ash.SQL_ID,
       blocking_session bsid
  from DBA_HIST_ACTIVE_SESS_HISTORY ash
  where event='buffer busy waits'
     and session_state='WAITING'
group by
       session_id
       ,sql_id
       ,blocking_session
       ,ash.p1
       ,ash.p2
Order by  1
/

gives

Def v_secs=3600 --  bucket size
Def v_days=1 --  total time analyze
Def v_bars=5 -- size of one AAS in characters
Def v_graph=80 

col aveact format 999.99
col graph format a80
col fpct format 9.99
col spct format 9.99
col tpct format 9.99
col aas format 9.99
col pct1 format 999
col pct2 format 999
col first format  a15
col second format  a15

Def p_value=4

select to_char(start_time,'DD HH24:MI'),
       --samples,
       --total,
       --waits,
       --cpu,
       (total/&v_secs) aas,
       --round(fpct * (total/&v_secs),2) aas1,
       fpct*100  pct1,
       decode(fpct,null,null,first) first,
       --round(spct * (total/&v_s

OK,  so wordpress got hacked. I’ve had problems with this in the past and tried tactical surgery, but this time decided to do a full re-install. My first attempt today left me with the wordpress blank screen of death, so here I’m outlining the steps I took that finally got the new version working:

UPDATE: thanks to Alex Gorbachev for pointing out that Oracle has a public yum for OEL which is compatible with REHEL and Oracle has Oracle certified packages:

Oracle Certified packages:

http://oss.oracle.com/el5/oracle-validated/
http://www.oracle.com/technetwork/articles/servers-storage-admin/extractingfilesrpm-444871.html

Public Yum:

http://public-yum.oracle.com/

A small but time consuming LINUX issue:

When installing on RHEL for both 10 and 11, I get errors that the following  libraries are missing

January 12, 2012 I thought that I would start this slightly off topic blog article with a bit of humor.  Seven months ago I wrote a blog article that refuses to move from the first position in the most visited articles on this blog.  In the process of trying to understand why a mathematics focused article [...]

You may have noticed that I’m having a little trouble keeping up to date on the blog at the moment – I know I’ve got several comments on Oracle Core to respond to but haven’t had time to look at them yet. Very briefly, though, I thought I’d point to a note that Doug Burns has just posted about John Beresniewicz’s presentation one “outliers” at the UKOUG conference.

Key feature: it supplies a query that could be very useful for capturing short, but nasty, events;  and has links to a couple of documents explaining what it’s trying to do and why. It’s a query that could do with more exercise on production systems so that Doug can get some feedback to JB about how effect it is, and how it could be improved.

Start here.

Back in http://dboptimizer.com/2010/07/26/oracle-10053-sql-trace-viewer/ I mentioned an Oracle 10053 trace file viewer. Well now there is another one with even more options and it’s free. Check out http://www.lab128.com/free_downloads.html from the same person who created lab128 the fastest Oracle database monitor in the West (or in the world for that matter, AFAIK). Here is an example screen shot:

Yesterday I talked about some of the things to consider when adding space to a tablespace using auto-extend for datafiles. This of course isn’t the only way to add space to a tablespace. You could simply add more datafiles. Indeed nearly a decade ago (scary!) I wrote The final reason for multiple datafiles (to spread [...]