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Index created with parallel clause

Oranew
Oranew asked
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I have a general question on performance. (Oracle 11g rel 2 with 20 CPU non-rac)
I created few  indexes with the parallel clause. Is this have to do anything in the select statements when the index is used in the select statement or inserts?

To be specific I have a table which is queried too often from the online queries/reports. Will it may create some performance  issues when the indexes on the tables are created using the parallel clause? or the index creation has nothing to do with the queries and it is only used to create indexes quickly (using parallel)  ?
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Senior Oracle DBA
Commented:
Parallel is only used in the index creation.  It has no effect on the queries that use the index after it is created.

Author

Commented:
I was reading this blog regarding the parallel query used in select when index is build as parallel?

I am a bit confused and I read in more than one blog:-
http://blog.tanelpoder.com/2007/06/23/a-gotcha-with-parallel-index-builds-parallel-degree-and-query-plans/
johnsoneSenior Oracle DBA

Commented:
I haven't seen an index do that after building with parallel.  If the degree is set, I guess it is possible.

You can check the degree on the index and then alter it to remove it if you want.  The steps are in the post.  However, that article is pretty old, so whatever version you are on now may not do that.

I would think that in an OLTP system where you don't want that many records back it wouldn't be an issue (as total amount of data returned is what is driving the change to parallel) and in a warehouse environment it would probably help.
Geert GOracle dba
Top Expert 2009
Commented:
when creating an index with parallel x, then the degree of the index gets set to that same x

this can really speed up index creation

after creating the index, you can reset the degree to 1

alter index index_name parallel 1;

or
alter index index_name noparallel;

Author

Commented:
The question is actually not fot speed the creation. As this new index will be put in the oltp database and it takes only less than 2 minutes to get created.
The question is after it get created Will it be used in query execution?
It is created with parallel but no degee is mentioned.
Thanks
The question is after it get created Will it be used in query execution?

The answer to that question has already been given = NO : http://www.experts-exchange.com/Database/Oracle/Q_28633653.html#a40658357