Index Range Scan and db file scattered read as session wait event

I was asked to check a session which was running for more than expected time on 11.2.0.3 single instance database.The session was running a simple select statement 05:03:09 SYS@xx4040 > @sqlid 9kpjtkdz1mzus old 9: sql_id = ('&1') new 9: sql_id = ('9kpjtkdz1mzus') SQL_ID HASH_VALUE SQL_TEXT ------------- ---------- ------------------------------------------------------------------------------------------------------------------------------------------------------ 9kpgmndz1mzus 2115632984 SELECT SC.ID FROM user.s_seq_cd SC … Continue reading Index Range Scan and db file scattered read as session wait event