DBCC trace 3213 Memory limit

Question

what's the fomular of determine the
Memory limit: 399 MB???

My server has 8GB ram

Answer 1

That memory limit is internally calculated by database engine and you do not have control over it. This is determined at the time of running backup and would be used to create memory buffers also. This memory limit is also influenced by buffercount size you have set, but again SQL Server will internally reach to the best memory limit based on runtime configuration. You do have control over Buffercount and maxtransfersize. Plus the trace flag 3213 which gives information is unsupported so we dont have any documentation.