| db_file_multiblock_read_count - reading too less blocks at a time [message #244618] |
Wed, 13 June 2007 09:08  |
Brayan
Messages: 315
Registered: June 2002
|
Senior Member |
|
|
Hi,
OS - HP Unix
Ver - 9.2.0.7
Appln: DSS System
SQL> select name, value from v$parameter where name = 'db_file_multiblock_read_count';
NAME VALUE
------------------------------ ------------------------------
db_file_multiblock_read_count 32
SQL>
But, in the trace file I notice following,
PARSE #8:c=20000,e=16022,p=0,cr=0,cu=0,mis=1,r=0,dep=0,og=4,tim=3458967830261
EXEC #8:c=0,e=87,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=4,tim=3458967830821
WAIT #8: nam='db file scattered read' ela= 8927 p1=23 p2=195144 p3=5
WAIT #8: nam='db file scattered read' ela= 14401 p1=24 p2=146849 p3=5
WAIT #8: nam='db file scattered read' ela= 4205 p1=76 p2=644179 p3=5
WAIT #8: nam='db file scattered read' ela= 8167 p1=80 p2=295674 p3=5
WAIT #8: nam='db file scattered read' ela= 6471 p1=82 p2=236309 p3=5
WAIT #8: nam='db file scattered read' ela= 8813 p1=83 p2=236279 p3=5
WAIT #8: nam='db file scattered read' ela= 5709 p1=84 p2=202659 p3=5
WAIT #8: nam='db file scattered read' ela= 14241 p1=86 p2=4574 p3=5
WAIT #8: nam='db file scattered read' ela= 5573 p1=4 p2=13289 p3=5
WAIT #8: nam='db file scattered read' ela= 1084 p1=23 p2=195149 p3=5
I just wonder, why it is reading only 5 blocks. Is my observation is correct? If, what could be the reason it is reading so less blocks.
Brayan.
|
|
|
|
|
|
| Re: db_file_multiblock_read_count - reading too less blocks at a time [message #244743 is a reply to message #244618] |
Thu, 14 June 2007 00:47  |
Brayan
Messages: 315
Registered: June 2002
|
Senior Member |
|
|
Hi Michael,
| Quote: |
- your extent size is 5 blocks (preferred reason as it is constant)
|
Yes, My table's extent size is 5 blocs (i.e 8192*5). It has inherited from tablespace(UNIFORM) parameters.
That mean to say that, it can read max 1 extent at a time.
In my query it was a Materialized view, do u suggest me alter the storage parameters and reresh complete?
Regards,
Brayan.
|
|
|
|
|
|
] 
Blog
Search
Help
Members
Register
Login
Home
