Isolation level in Connection Pool

What are Isolation level in Connection Pool Setting ??


They are applicable for ODBC and DB2 gateways only. 

The Level options:

Committed Read:    Locks are held while the data is read to avoid dirty reads. Data can be changed before the transaction ends with that connection.

Dirty Read:   0 Locking. Can read uncommitted or dirty data, change values in data during read process in a transaction. Least restrictive of all types.

Repeatable Read:  Places locks on all data used in a query so that nobody can update the data. However new rows can be inserted by other users but will be available in later reads in the current transaction.

Serialization:   Places a range lock on data set preventing other users to insert or update the rows in data set until the transaction is complete. Most restrictive of all.

Maximum Connections in Connection Pool

Setting up Maximum Connection in Connection Pool is one of the main parameter which affect performance.

The default value of 10 is usually too low (it will cause queuing) but setting it too high will eat up memory and the BI Server process may not even start (1024 kb of server memory is consumed per connection ) .

So a general rule is to follow the below formula to set up Maximum Connections.

Maximum number of connections =   Total  number of reports per dashboard *  20% of concurrent users 

Point to note: It 20% of concurrent users .NOT 20% of total users.  Generally, In any given time at-least 25% of user will be accessing dashboard.