Oracle RAC Performance Tuning specially gc cr multi block request wait event

by / 2010-2011 / Published in Oracle RAC Basic

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This article is for advance RAC DBA which covers Oracle 9i RAC,Oracle 10g RAC,Oracle 11g RAC.It covers Tuning of Wait event called "gc cr multi block read" , Global Cache Services and Cache Fusion of Oracle Real Application Cluster. This is very useful article for remote database services in Oracle RAC tuning guide.

Oracle real application cluster performance tuning is very tough because you need to check so many things and apply your experience using smart brain. Sometimes you could get reverse impact. Expert remote dba will be able to tune in this situation using his or her high experience and expertise.

How to tune "global cache services" and "gc cr multi block request" wait event?

LMS process called as Lock Manager Server Process , also called the GCS (Global Cache Services) process. Main task of this process is to transport blocks across to the nodes of Oracle RAC for "cache fusion" transportation. If any consistent read request found from another connected node then LMS process makes consistent read image of block and transport it to across the nodes for full filling client's consistent read request. This images transports using High Speed Interconnet process to and from remote nodes.

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Multi block read called as full table scan and it uses multiple blocks and mode large read request. While during cache fusion, a global cache service makes same blocks to consitent read images and transport same blocks to remote node across Oracle Real Application Clusters (RAC).

Wait event "gc cr multi block request" reflects problem of transporting data across to nodes in cluster specially when found mode CPU consume and mode network busy during operations.

We are providing some useful tips for tuning but you should need to apply your mind before deploy these tips. We are not offering any guarantee because in every sitation and condition, resolation will be different. You should need to investigate situation accurately before applying this solution. For more details kindly download document called "Perfomance and Tuning of Oracle RAC databases-1" from our website as per following link....DOWNLOAD

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