FAQS

1.How can I get the largest amount of physical reads by any query?

   select disk_reads, sql_text from v$sqlarea where disk_reads >1000 order by disk_reads desc ;

 

2. V$FIXED_TABLE

This view displays all dynamic performance tables, views, and derived tables in the database

 

3.What is the difference between V$ and GV$ , also V$and V_$,X$?

These “$” views are called dynamic performance views. They are continuously updated while a database is open and in use, and their contents relate primarily to performance.
The actual dynamic performance views are identified by the prefix V_$. Public synonyms for these views have the prefix V$. You should access only the V$ objects, not the V_$ objects.
For almost every V$ view, Oracle has a corresponding GV$ (global V$) view. In addition to the V$ information, each GV$ view contains an extra column named INST_ID of datatype NUMBER. The INST_ID column displays the instance number from which the associated V$ view information was obtained.

X$ is table, is drived table.

 

4.How do you find out the unix process id of a database session?

Some times you might want to get the unix process details of a database session. You have the Oracle session details. Just map them with paddr column from v$process ! You're done.

e.g.

SQL> select p.spid from v$session s, v$process p where s.sid=16 and s.paddr=p.addr

SPID
---------
16750

5.

你可能感兴趣的:(AQS)