gc buffer busy waits

  • From: lyallbarbour@xxxxxxxxxxxxxxx
  • To: oracle-l@xxxxxxxxxxxxx
  • Date: Wed, 09 Mar 2011 13:47:08 -0500

Not sure if this has been asked, but i just don't know what to do with the 
information that ADDM and ASH reports give me.

We have a large table DA.ST_INV_ITEMS_HS, almost 690,000 rows.  Big table with 
lots of columns.  The table takes up 632Meg.  It has only 173 extents.  8k 
block database 10gR2 RAC 2 node cluster.  Tons of cluster waits on that table.  
I always thought that that means that one session has queried off this table, 
locked those blocks or extents in memory on one node and a session on the other 
nodes is waiting for those blocks or extents to be unlocked.

can someone explain what the ASH report means about Top DB Objects?


Top DB Objects

 With respect to Application, Cluster, User I/O and buffer busy waits only.


Object ID
% Activity
Event
% Event
Object Name (Type)
Tablespace

54768
 
17.04
 
gc buffer busy
 
8.80
DA.ST_INV_ITEMS_HS (TABLE)
 
USERS

 
 
 
 
gc cr multi block request
 
7.70
 



 

 


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