help: high "gc busy buffer"

From: charles <>
Date: Tue, 11 Jan 2011 14:15:37 -0800 (PST)
Message-ID: <>

Dear group,

We are using Oracle 10g on linux RAC with 4 nodes. We have a small table, no more than 300 rows, but most people will update/delete/ insert on it during load testing. And ASH report shows it is the cause of this contention.

EVENT                                 CNT
------------------------------ ----------
gc current retry                        4
gc current grant 2-way                 31
gc current request                     47
gc cr request                          66
gc cr multi block request              69
gc current block busy                  79
gc cr grant 2-way                      81
gc current grant busy                 113
gc current block 2-way                416
gc cr block busy                      420
gc cr block 2-way                     568
gc buffer busy                       6448

All the "gc buffer busy" points to one small table, no index/triggers on this table, which 2000 update, 1800 insert, 1600 select. The table is created in a ASSM tablespace, so i guess freelist is not going to help here.

Could somebody give me some advice?

Thanks Received on Tue Jan 11 2011 - 16:15:37 CST

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