What means "gc cr disk read" event?

Question

Hi everybody,
I have a process that executes four times per day, and in a specific execution the process consome most time. The quantites of data to be process in each moment is same.
Last day, I enabled trace to comper and I get the event gc cr disk read very difente from other execution.
Some one can explain what means the gc cr disk read event?
I have looking on the net but i found no documentation about it?
Thanks
Marcelo Barleta

Answer 1

MA®CELO  BA®LETA™ wrote:
Hi everybody,
I have a process that executes four times per day, and in a specific execution the process consome most time. The quantites of data to be process in each moment is same.
Last day, I enabled trace to comper and I get the event gc cr disk read very difente from other execution.
Having done a search for exactly "gc cr disk read" on Google I can confirm that the available information on that particular wait is hard to find - but we can guess that it's cluster related (gc = global cache), for a consistent read (cr) and involves a disk read.
Possibly it's an indication that one node has requested a CR block from another node and been told that the holding node has been told to write the CURRENT block to disk (fusion write) and the calling node will have to read the current block and sort our read consistency for itself.
This would tend to suggest that you have more than two nodes in your cluster, and you have some blocks which (on occasion) are rapidly updated from all three nodes at more or less the same time.
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
http://www.jlcomp.demon.co.uk
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