I have a query that executes in 3 to 4 seconds to fetch 500 records but when i am reading the result using IDataReader
it is reading first 22 rows very fastly after reading 22nd row it is taking 1 minute time and reading next 22 rows fastly
like this for every 22 rows it is taking 1 minute.
I'm using Oracle-11g r1 DB and ODP.NET-18.104.22.168.10
ODP.NET 22.214.171.124.10 was a beta version IIRC. I don't know what your specific problem is necessarily. First thing I generally recommend to people is to upgrade to the latest ODP.NET version (126.96.36.199) to ensure you are not hitting an old bug. ODP.NET 188.8.131.52 is compatible with an Oracle 11.1 DB.
Performance issues are very difficult to diagnose via discussion forum.