Checking resources in the Global Directory in an Oracle RAC environment involves querying specific views and using Oracle-supplied utilities that provide information about resource states and ownership. Here are the main methods to check resources in the Global Directory:

1. Using Oracle Dynamic Performance Views (V$ Views)

Oracle provides several dynamic performance views (commonly referred to as V$ views) that can be queried to gather information about resources managed by the Global Directory.

Key V$ Views:

• V$GES_RESOURCE: This view provides information about Global Enqueue Service (GES) resources.

SELECT * FROM V$GES_RESOURCE;

• V$GES_ENQUEUE: This view shows details about enqueue requests and grants for global resources.

SELECT * FROM V$GES_ENQUEUE;

• V$GCSPROCESS: This view displays information about the Global Cache Service (GCS) processes.

SELECT * FROM V$GCSPROCESS;

• V$GCSHVMASTER_INFO: This view provides information about which instances are the masters for various GCS resources.

SELECT * FROM V$GCSHVMASTER_INFO;

• V$GCSTHINGS: This view shows information about various GCS-managed objects, such as data blocks and buffers.

SELECT * FROM V$GCSTHINGS;

• V$LOCK: This view provides information on all types of locks held in the system.

SELECT * FROM V$LOCK;

2. Using Oracle Grid Infrastructure Utilities

Oracle Clusterware Management (CRSCTL)

CRSCTL is a command-line tool used to manage Oracle Clusterware resources. You can use it to check the status of resources managed by the Global Directory.

• Check Resource Status:

crsctl status resource -t

This command displays the status of all resources in a tabular format, showing their current state and which nodes they are running on.

Oracle Cluster Health Monitor (CHM)

CHM monitors the health of Oracle RAC and provides detailed diagnostics information. You can use CHM to get insights into the status and performance of resources.

3. Using Oracle Enterprise Manager (OEM)

Oracle Enterprise Manager provides a graphical interface to monitor and manage Oracle RAC resources. It offers detailed views and dashboards that show the status of resources, lock contention, and other performance metrics.

• Cluster Database Home Page: Navigate to the Cluster Database home page to see an overview of the RAC environment.
• Performance Pages: Use performance-related pages to drill down into specific areas like Global Cache Service (GCS) and Global Enqueue Service (GES).

Example Queries

Here are some example SQL queries to check resources in the Global Directory:

• View GES Resources:

SELECT INST_ID, RESOURCE_NAME, RESOURCE_TYPE, BLOCKED, GRANTED, CONVERT, OPEN_COUNT FROM GV$GES_RESOURCE;

• View Enqueue Information:

SELECT INST_ID, SID, TYPE, ID1, ID2, REQUEST, LMODE FROM GV$GES_ENQUEUE;

• View Lock Information:

SELECT INST_ID, SID, TYPE, ID1, ID2, LMODE, REQUEST, CTIME, BLOCK FROM GV$LOCK;

Conclusion

Monitoring and checking resources in the Global Directory in an Oracle RAC environment is essential for ensuring data consistency, performance optimization, and high availability. By using Oracle’s dynamic performance views, command-line utilities, and graphical tools like Oracle Enterprise Manager, administrators can effectively manage and troubleshoot RAC resources. Regular monitoring helps in early detection of issues and ensures the smooth operation of the RAC system.