ahmad.b

Database Event GC Busy Buffer Acquire

Discussion created by ahmad.b on May 29, 2013
Latest reply on May 31, 2013 by Chris_Hackett
Hi All,

My database was complaining the Cluster wait event of GC Busy Buffer Acquire, after doing analysis I found an Insert DML causing contention on the following Tables/Indexes:

Table CMN_SESSIONS
Indexes CMN_SESSIONS_PK CMN_SESSIONS_U1 CMN_SESSIONS_U2

Table CMN_SESSION_AUDITS
Indexes CMN_SESSION_AUDITS_N1 CMN_SESSION_AUDITS_N2

The index of CMN_SESSIONS_U2 is a nonunique function-based index, based on NLS_UPPER(TOKEN), while the normal index of CMN_SESSIONS_U1 is based on column TOKEN too!!!!! Do we really need the index of CMN_SESSIONS_U2 ????

Do really need the indexes of CMN_SESSION_AUDITS_N1 and CMN_SESSION_AUDITS_N2 on table CMN_SESSION_AUDITS ???

Please shed some light, thank you

Outcomes