Mcq, Fundamentals Of Financial Management

launched yesterday in Milan

Yesterday I was at the launch of Oracle 11gR2 the Hilton hotel in Milan. I was hoping to meet some of the group DBA Oracle DBA Italy on Facebook, but it was not the case, although the rooms were crowded.

With great pleasure I have known Alberto Era, which I often read interesting articles on Oracle. I only found out yesterday that has also opened a blog .
I talked to Albert about a site aggregator of reference for all DBA Italian, in Italian, in order to also collect his impressions. Apart from the differences, we agree that it would take a greater support and enthusiasm from the other DBA.

Although I have followed as far as possible all the ads at the exit of 11gR2, I was lost in a strange and unusual new Oracle Exadata 2: Columnar Hybrid Compression . Oracle database is going to " columnar ? Even Kevin Closson he's busy and it seems that the Oracle version has some extra features (hence the term "hybrid").

Must try the Redefinition -based edition, which promises to update the db objects in a transparent manner during an upgrade of the application. In practice you no longer have downtime for upgrades. The "issues" are defined at the database level.

I saw a slide on one-node RAC, in practice a particular licensing for which we build a two-node RAC in an instance where there is always the most active, while the other car are all active components except for the RAC instance. It is ultimately an active / passive cluster controlled by clusterware. As I understand it also has the defect (it) to exist only for enterprise edition.

An excellent use of the new cluster filesystem as ACFS is shared ORACLE_HOME. In the event of an upgrade of the home, you can also use the snapshot feature to possibly go back if necessary, but only with regard to the binaries, not the db.

ideas Oracle home there. I will update you soon on the evidence before 11gR2 Grid Infrastructure I've just completed.

Color Lipstick For Blonde Fair Skin

In the past I have addressed the problem of related columns and sampling dynamic as an alternative.

In 11g, using a new method of collecting statistics, you can specify the column groups which to measure the correlation, in some ways an extension of the concept of uneven distribution of data (skewness) .

To illustrate more general than that In the past, where the correlation is less obvious. In the example of dynamic sampling on the post I had used two columns with equal values \u200b\u200bfor each row, but now use a more real case: imagine that we have three sets of values, the values \u200b\u200bof the first around 1000, the second around 2000, third round 3000:

 SQL> desc CORREL 
 Name Null? Type ------------------- -------- -------------- 
 
 TAG NOT NULL VARCHAR2 (16 ) 
 VAL NOT NULL NUMBER (38) 
 
 SQL> insert into CORREL select 'TYPE1', 1000 + TRUNC (DBMS_RANDOM.VALUE (0,100)) from all_objects; 
 
 61122 rows created. 
 
 SQL>  select * from correl where rownum  < 10;
  
 TAG                     VAL 
 ---------------- ---------- 
 TIPO1                  1035 
 TIPO1                  1012 
 TIPO1                  1003 
 TIPO1                  1090 
 TIPO1                  1070 
 TIPO1                  1061 
 TIPO1                  1004 
 TIPO1                  1020 
 TIPO1                  1032 
  
 9 rows selected. 
  
 SQL> insert into correl select 'TIPO2', 2000+TRUNC(DBMS_RANDOM.VALUE(0,100)) from all_objects; 
  
 61122 rows created. 
  
 SQL> insert into correl select 'TIPO3', 3000+TRUNC(DBMS_RANDOM.VALUE(0,100)) from all_objects; 
  
 61122 rows created. 
 
 SQL> commit; 
 
 Commit complete. 
 

At this point we take the standard statistics and see that the optimizer, for any value (not applicable) in the range max-min of the column, predicts that there are 204 lines:

 SQL> exec dbms_stats . gather_table_stats (user, 'CORREL', estimate_percent => 100); 
 
 PL / SQL procedure successfully completed. 
 
 SQL> explain plan for select * from CORREL WHERE tag = 'TYPE2' and val = 1200; 
 
 Explained. 
 
 SQL> select * from table (dbms_xplan.display) 
 
 PLAN_TABLE_OUTPUT 
 -------------------------------- -------------------------------------------------- --------------------------------------------------  
 Plan hash value: 469411154 
  
 ---------------------------------------------------------------------------- 
   AND "TAG"='TIPO2') 
  
 13 rows selected. 
  
  
 Ma ora prendiamo le statistiche utilizzando i gruppi di colonne: 
  
 SQL> exec dbms_stats.gather_table_stats(user, 'CORREL', method_opt => 'FOR COLUMNS (TAG,VAL) SIZE SKEWONLY', estimate_percent => 100); 
  
 PL/SQL procedure successfully completed. 
  
 SQL> explain plan for select * from correl where tag = 'TIPO2' and val = 1201; 
  

Explained.

SQL> select * from table(dbms_xplan.display);

  
 PLAN_TABLE_OUTPUT 
 ------------------------------------------------------------------------------------------------------------------------------------  
 Plan hash value: 469411154 
  
 ---------------------------------------------------------------------------- 
  AND "TAG" = 'TYPE2') 
 
 13 rows selected. 
 
 
 is clear that things are much better: the estimate is dell'optimizer of 611 lines, although there are no rows with the value val is 1201. 
 
 But the big advantage is that now the estimate of about 600 lines are valid for ranges of numbers: 
 
 SQL> explain plan for select * from CORREL WHERE tag = 'TYPE2' and val = 2023; 
 
 Explained. 
 
 SQL> select * from table (dbms_xplan.display) 
 
 PLAN_TABLE_OUTPUT 
 -------------------------------- -------------------------------------------------- -------------------------------------------------- 
 Plan hash value:  469411154 
  
 ---------------------------------------------------------------------------- 
  
 

13 rows selected.

SQL> select count (*) from CORREL WHERE tag = 'TYPE2' and val = 2023;

COUNT (*) ----------

 
 
 
 645 1 row selected. 
 
 
 probably with some action on the histogram of the group of columns is also possible to correct the false estimate due to the very uneven distribution of numbers in column val. 
 
 
 

Accuracy Of Hiv Antibody Tests After 7 Weeks

related columns in 11g Release 2 Oracle Exadata




Last night, Larry Ellison himself has presented the new version of its Database Machine, called Oracle Exadata

version 2. It is very interesting that the Sun is completely hardware used on Intel. I looked

The live, but rather a series of praise for the product and a list of performance factors (2x, 4x, 10x, 30x, etc..) buckled to each of the components, I have heard many technical details.
The most important is certainly the technology FlashFire essentially a smart cache at the storage level server. The database server take into account the presence of the cache when developing the implementation plan of the query.

It has been said many times that Oracle Exadata version 2 is the fastest car ever built, and how that data warehousing (hear hear) for OLTP! You have to find someone willing to spend a lot 'to take her home.

Update

22-9: The webcast is now available here

.

Undf Fájl Lejátszás

Some news dell'optimizer 11g

In 11g there are several innovations with regard to the cost-based optimizer:


null-aware anti-join
: interesting for me because I've faced a few days ago. When you have a query like: SELECT ...

T1.X FROM T1 WHERE NOT IN (SELECT ...); T2.Y WHERE

T2.Y and is a column that can have null values, 10g and earlier can use an execution plan that leads to an excess of consistent gets (mainly CPU), and then to a query very slow. In 11g it is possible the anti-join. Council the excellent article Greg Rahn for those who want to learn more.


Join Predicate Pushdown: When there is a join between a table and a view, the join condition (ie TX = VY) is computed directly in the table view that contains the column: TX = TV.Y . This will take advantage of any indexes present, even with that view contains group by, distinct and join



Moving the group by : in the case of a join with GROUP BY, the optimizer is able to move the group by and function within a group view, which reduces the lines on which to make the join.

Deleting DISTINCT : the optimizer analyzes the different blocks in a query is made, and where possible eliminate the DISTINCT.

In many ways it seems that all these optimizations are designed to avoid delays due to common programming errors.

Woman Wearing Penny Loafers

Nuovi processi di background in 11g

Oracle 10g accustomed us to a proliferation of background processes, especially with regard to the RAC, but breaks all 11g and introduces a number of processes dedicated to the tasks most imaginative:

DBRM (database resource manager) tax the resources of the Resource Manager

DIA0 (diagnosability process) solves the deadlock and detects blocks

EMNC (Event monitor coordinator) manages events and alerts

FBDA (flashback data archiver process) archives the historical data table that is activated and maintains the archive archive flashbak

GTX0

-j (global transaction ) allows global transactions

distributed (XA) in RAC environment. Currently XA transactions are only possible on a single node for client

• gmon manages the disks in the ASM diskgroup


• KATE handles the I / O ASM a disk that went offline for some reason


• MARK brand as invalid allocation units scritte su dischi ASM che sono andati offline


• SMCO (space management coordinator) gestisce l'allocazione e la deallocazione dello spazio su disco in maniera proattiva


• VKTM (virtual keeper of time) mantiene l'orologio di riferimento, che viene aggiornato ogni secondo
Col tempo ci sarà occasione di approfondire i compiti dei nuovi processi.

Friends Of Milena Velba

Lancio di 11gR2 a Milano il 24: ci vediamo?


Giovedì 24 settembre si terrà a Milano un

evento per il lancio di Oracle 11g release 2 .

Io ci sarò; se qualcuno di voi ci sarà, potrebbe essere un'occasione per incontrarsi, fare conoscenza e scambiare some opinion.
Leave your messages in the comments, so there is easier.

promises to be interesting to open discussions with beta testers from 11 to 12 and afternoon sessions that summarize the new features.

Ver Fotos De Juste Bibe

11gR2 Generally Available

came out today the release 2 of Oracle 11g .

If you have the same news that had 10gR2 to R1, promises to be interesting tests and comparisons.

Update 15:09: The first requirements for installation are found in Metalink document 880936.1 (32 bit) and 880989.1 (64 bit).

Now Clusterware became

Grid Infrastructure? :-)