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Single query to access multiple RAC nodes [message #643407]

Wed, 07 October 2015 03:06

sinpeak
Messages: 59
Registered: January 2011
Location: india

Member

Hi,

I am a beginner and dont know much about RAC so the title of this post may not be valid.

My client is planning to have multiple RAC nodes and I hear that the data in tables will be distributed across the RAC nodes based on some table column ( CODE_ID ) common across all tables in the database.
Example if CODE_ID = 1 then the data will be in RAC NODE = A and so on.

We already have our SQLs implemented for the client.

Question-1:
------------
We want to know do we need to change our SQLs...if RAC nodes are enabled as explained above.
Example: an SQL is required to select all rows from a table that has CODE_ID column but the data to be selected is not specific to CODE_ID rather the select is scanning the table based on some other condition. So if the SQL is :

Code: [Select all] [Show/ hide]

SELECT COL1,COL2,COL3
FROM MANAGEDACCOUNTS
WHERE COL1 = 'A_EXP'
AND COL2 = 7

So will this work even if RAC nodes are enable as explained above ?

Question-2:
-----------
There will be more than 1 active RAC node.
So, will there be multiple TNSNAMES entries and multiple SIDs and multiple service names based on the RAC nodes ?

Question-3:
-----------
If there are multiple TNSNAMES entries/SIDs/Service names , then will the SQL mentioned above ( in Question-1 ) work if the user is connected using a particular TNSNAMES entry/SID/Service name ( which is specific to a RAC node ) ?
I mean will the SQL scan across the table data in all RAC nodes OR only look into the table data for the RAC node which is linked to the connected TNSNAMES/SID/Service name.

Thanks.

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Re: Single query to access multiple RAC nodes [message #643410 is a reply to message #643407]

Wed, 07 October 2015 04:32

John Watson
Messages: 8976
Registered: January 2010
Location: Global Village

Senior Member

This that you have heard,Quote:

I hear that the data in tables will be distributed across the RAC nodes based on some table column ( CODE_ID ) common across all tables in the database.
Example if CODE_ID = 1 then the data will be in RAC NODE = A and so on.

is not correct. Use of RAC is transparent to your SQLs. You do not need to do anything, other than ask your DBA to confirm this. If he cannot, you need new DBA.

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