SID               :   Session Identifier.
Serial#          :   Uniquely identifies Session Objects.
Username     :   Database User.
Command     :   Command being executed, the one which hs been parsed.
                        For example.
                        SELECT, ALTER, CREATE TABLE etc.
Server : Type of DB server Shared | Dedicated | None
Status : Status of Session.
ACTIVE.
INACTIVE.
KILLED
SNIPED.
CACHED.
OSUSER : Client OS username.
Process : Client OS process ID
Machine : Client OS machine name
Terminal : Client OS terminal ID.
Program : Client OS program Name.
Type : Type of Process whether background or user initiated.
SQL_hash_value : Hash value to uniquely identify the SQL being executed.
Logon_time : Time of logon
State :
0 - WAITING (the session is currently waiting)
2 - WAITED UNKNOWN TIME (duration of last wait is unknown)
1 - WAITED SHORT TIME (last wait <1/100th of a second)
0 - WAITED KNOWN TIME (WAIT_TIME = duration of last wait)
Service_name : Service Name of the session.
SQL_trace : Indicates whether tracing is enabled or not.

 

 

PID : Oracle Process Identifier
SPID : Operating System Process Identifier.
Username : OS username
PGA_USED_MEM : pga memory currently used by the proces
PGA_ALLOC_MEM :  PGA MEMORY CURRENTLY ALLOCATED BY THE PROCESS
PGA_FREEABLE_MEM : Allocated PGA memory which can be freed.
PGA_MAX_MEM :  Maximaul PGA memory allocated by the process.

 

 

dba_dml_locks
dba_ddl_locks
dba_waiters
dba_blockers

v$system_event
v$session_event
v$session