I have four simple (non-partitioned, non-clustered, not views, not object type – really I’m not trying to be cunning or devious here) heap tables, and write a query that joins them: select /*+ leading(t1 t2 t3 t4) use_hash(t2) use_hash(t3) use_hash(t4) */ count(t1.small_vc), count(t2.small_vc), count(t3.small_vc), count(t4.small_vc) from t1, t2, t3, t4 where t2.id2 = t1.id1 and t3.id3 [...]
In a previous post (GATHER_PLAN_STATISTICS) I mentioned that SQL Profiles and Baselines can both be applied to a single statement. In this case, it appears that the hints are merged. The Notes section of the XPLAN output shows that both the Baseline and the Profile are in effect. I wanted to prove to myself that [...]
December 10, 2010 (Back to the Previous Post in the Series) (Forward to the Next Post in the Series) In the interest of interesting quotes, a quote that I found in the “Oracle Tuning the Definitive Reference Second Edition” book on page 988: “Production DBA’s spend weekends reorganizing their data structures, returning them back into their original, [...]
If you're just beginning to implement Oracle 11g, you need to be aware of the Automatic Diagnostic Repository (ADR). It has nothing to do with AWR, ADDM, ASM, ASSM, or any of the other acronyms Oracle has come up with over the last two releases.
In terms of the database, ADR could be a great thing. It's integration with Enterprise Manager is probably one of the best parts about the feature.
This post is inspired by one of my colleagues, who had small difficulty while interpreting parallel MERGE execution plan. This is the step-by-step explanation I gave him. 1. Create tables. SQL> create table t1 2 as 3 select 4 level as c1, 5 level as c2, 6 rpad('x',100) as c3 7 from 8 dual 9 [...]
This post was inspired by Maris Elsins, who tweeted: “Someone gzipped the redo logs of a running no-backups test DB. It was a nice surprise when I tried to start it up after shut immediate :D” and then “So the quiz: How do I recover from this situation?”
I solved it with ease, because 3 years [...]
As a large number of the Oracle community would I guess be in the process of upgrading to 11g (Release 2 and its patch is already available), I am including some presentations taken from the 11g Upgrade Workshop which was conducted by Oracle Corp staff members Roy Swonger & Mike Dietrich.
The workshop was highly detailed but very practical in nature and is a must read for anyone who has not attended these workshops, but are considering upgrading to 11g in the near future.
Here are the workshop slides:
PL/SQL in 23th in TIOBE Index for December 2010. It's was in 20th place last month!
December 9, 2010 (Forward to the Next Post in the Series) In the interest of interesting quotes, a quote that I found in the “Oracle Tuning the Definitive Reference Second Edition” book on page 995: “In the 1970s, Moore’s law was introduced, stating that processor costs were always falling while speed continued to improve. However, as Oracle [...]
Fim do Dia (No Lado Quente Da Saudade)
Esperei-te no fim de um dia cansado
À mesa do café de sempre
O fumo, o calor e o mesmo quadro
Na parede já azul poente
Alguém me sorri do balcão corrido
Alguém que me faz sentir
Que há lugares que são pequenos abrigos
Para onde podemos sempre fugir
Da tarde tão fria há gente que chega
E toma um café apressado
E há os que entram com o olhar