ISOLATION LEVELS IN OBIEE

Isolation Level In Connection Pool

It sets the value for every transaction on the connection between OBI and Database, connected as a back end process.

The isolation level controls the default transaction for each and every statements issued by a connection as default locking behavior. The connection remains same until the user changes the properties. 

•     Dirty Read
• Committed Read
• Repeatable Read
• Serailizable

Dirty read

Dirty Read is the least level in the isolation of restriction of data and its values. The level of the dirty ready isolation level is ‘Zero’ Locking. On this level it’s probable to read the dirty data, free data, change values in the data. The rows will appear or disappear in the data set before the end of the transaction.

Dirty data is data that needs to be cleaned before being query to obtain correct results. Duplicate records, records with inconsistent naming conventions, or records with incompatible data types as to be cleaned.

Committed read

No Duplicate rows of transaction with clear data and consistence maintaining of results, Specifies that shared locks are held while the data is read to avoid dirty reads. However, the data can be changed before the end of the transaction, resulting in non repeatable reads or phantom data.

Repeatable read

Places locks on all data that is used in a query, preventing other users from updating the data. However, new rows can be inserted into the data set by another user and are included in later reads in the current transaction.

Serializable

 Places a range lock on the data set, preventing other users from updating or inserting rows into the data set until the transaction is complete. This is the most restrictive of the four isolation levels. Because concurrency is lower, use this option only if necessary.