"Can you please help me to resolve this and what is TCP Socket (KGAS)?"
Could it be because your mail server is down?
People say that TCP Socket (KGAS) is an Oracle application that uses DBMS_JOB to send out large amounts of emails, so it may be that it is waiting on the email server to respond.
You have two choices with TCP Socket (KGAS) waits, beef up your e-mail server or move the e-mails to another Oracle server.
Also see here on TCP Socket (KGAS).http://momendba.blogspot.com/2007/03/tcp-s...wait-event.html
was experiencing waits on "TCP Socket (KGAS)" event. Upon investigation, we found out that it was because the mail server was down and the procedure tries to open a new connection with the SMTP server and it takes 75 seconds to timeout on IBM-AIX.