dplinnane
asked on
query to find PARALELL or NOPARALLEL on a table
I want to run a query to see what tables have parallel and noparallel enabled.
database oracle 10g
database oracle 10g
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dplinnane,
I have DEFAULT in my database.
From the Oracle documentation for ALL_TABLES (http://download.oracle.com/docs/cd/B28359_01/server.111/b28320/statviews_2105.htm):
DEGREE VARCHAR2(10) Number of threads per instance for scanning the table, or DEFAULT
INSTANCES VARCHAR2(10) Number of instances across which the table is to be scanned, or DEFAULT
lwadwell
I have DEFAULT in my database.
From the Oracle documentation for ALL_TABLES (http://download.oracle.com/docs/cd/B28359_01/server.111/b28320/statviews_2105.htm):
DEGREE VARCHAR2(10) Number of threads per instance for scanning the table, or DEFAULT
INSTANCES VARCHAR2(10) Number of instances across which the table is to be scanned, or DEFAULT
lwadwell
dplinnane,
so:
DEGREE=DEFAULT = PARALLEL ( DEGREE DEFAULT )
lwadwell
so:
DEGREE=DEFAULT = PARALLEL ( DEGREE DEFAULT )
lwadwell
ASKER
A quick question on parallel
select * from sys.V_$INSTANCE;
The value in the column PARALLEL returns NO does that mean that you cannot run any queries in parallel?
select * from sys.V_$INSTANCE;
The value in the column PARALLEL returns NO does that mean that you cannot run any queries in parallel?
ASKER
I asked about the NOPARALLEL because I am doing some tuning in a data warehouse where they have some very large partitioned tables all the tables are set to NOPARALLEL, they have 12 cpu's and 128 Gigs of ram. reports are taking forever to run, I guess its time to make some of these tables PARALLEL.
dplinnane,
no I don't think so, again from the manual
PARALLEL VARCHAR2(3) Indicates whether the instance is mounted in cluster database mode (YES) or not (NO)
for parallel SQL you need to check your init parameter PARALLEL_MAX_SERVERS from memory. Look at
"show parameter parallel"
lwadwell
no I don't think so, again from the manual
PARALLEL VARCHAR2(3) Indicates whether the instance is mounted in cluster database mode (YES) or not (NO)
for parallel SQL you need to check your init parameter PARALLEL_MAX_SERVERS from memory. Look at
"show parameter parallel"
lwadwell
dplinnane,
This is just my personal opinion - so take it as you wish, I am sure you can get many different views on this.
Be careful setting the parallel degree at the table level - at this may globally affect every SQL touching the table. If all of them are doing full table scans - then parallel can help. Parallel can be applied at the SQL level as a HINT.
lwadwell
This is just my personal opinion - so take it as you wish, I am sure you can get many different views on this.
Be careful setting the parallel degree at the table level - at this may globally affect every SQL touching the table. If all of them are doing full table scans - then parallel can help. Parallel can be applied at the SQL level as a HINT.
lwadwell
ASKER
PARALLEL_MAX_SERVERS=240, thanks for the advice I'll keep that in mind.
ASKER
where degree=1.
I looked on another schema and found 2 examples where degree=2 and the tables were set to parallel.
select distinct degree from all_tables returned values 1,2 I did not see any DEFAULT value.
In conclusion
DEGREE=1 = NOPARALLEL
DEGREE=2 = PARALLEL ( DEGREE 2 INSTANCES 1 )
DEGREE=n= PARALLEL ( DEGREE n INSTANCES 1 )