The following scalar functions return statistical information about the system:
| [@@CONNECTIONS](../../t-sql/functions/connections-transact-sql.md) | [@@PACK_RECEIVED](../../t-sql/functions/pack-received-transact-sql.md) |
| [@@CPU_BUSY](../../t-sql/functions/cpu-busy-transact-sql.md) | [@@PACK_SENT](../../t-sql/functions/pack-sent-transact-sql.md) |
| fn_virtualfilestats | [@@TIMETICKS](../../t-sql/functions/timeticks-transact-sql.md) |
| [@@IDLE](../../t-sql/functions/idle-transact-sql.md) | [@@TOTAL_ERRORS](../../t-sql/functions/total-errors-transact-sql.md) |
| [@@IO_BUSY](../../t-sql/functions/io-busy-transact-sql.md) | [@@TOTAL_READ](../../t-sql/functions/total-read-transact-sql.md) |
| [@@PACKET_ERRORS](../../t-sql/functions/packet-errors-transact-sql.md) | [@@TOTAL_WRITE](../../t-sql/functions/total-write-transact-sql.md) |
All system statistical functions are nondeterministic. This means these functions do not always return the same results every time they are called, even with the same set of input values. For more information about function determinism, see Deterministic and Nondeterministic Functions.