In this post, we'll walk through a real-world scenario where a customer faced Oracle database connection issues and performance limitations. We'll discuss the problem, our diagnostic process, the solution implemented, and the results achieved.
Problem Statement
A customer reported the following issues:
1.
Unable to connect to Oracle database (DBCS) in OCI Classic from DataSync on their laptop outside the cloud
2.
Connection from SQLDeveloper on the same laptop works
3.
Expecting the number of database sessions to increase to 400 soon
Problem Diagnostics:
We started by investigating the connection methods and configurations:
1.
Checked connection definitions:
•
DataSync: Uses Service Name
•
SQLDeveloper: Uses SID
2.
We attempted to connect via SQLDeveloper using Service Name, which also resulted in an error.
3.
When trying to connect via SQLPlus on the DBCS VM instance, we encountered the following error:
ORA-00020: maximum number of processes (150) exceeded
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This error indicated that we were hitting resource limitations on the database server.
Solution:
To address these issues, we implemented the following solutions:
1. Resource Usage Assessment
First, we evaluated the current resource usage:
•
VM Physical memory available: 15GB
•
SGA Size / SGA Max Size: 5GB / 5GB
•
PGA Size: 3GB
2. Increase SGA Size
We decided to increase the SGA size to 6GB to provide more memory for database operations:
ALTER SYSTEM SET SGA_TARGET=6144M SCOPE=SPFILE;
ALTER SYSTEM SET SGA_MAX_SIZE=6144M SCOPE=SPFILE;
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3. Increase Process and Session Limits
To accommodate the expected increase in database sessions, we increased the process and session limits:
ALTER SYSTEM SET PROCESSES=1000 SCOPE=SPFILE;
ALTER SYSTEM SET SESSIONS=1600 SCOPE=SPFILE;
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4. Restart Database
After making these changes, we restarted the database to apply the new settings.
Results
Following the implementation of these changes, we observed:
•
SGA size increased to 6GB
•
Process limit increased to 1000
•
Session limit increased to 1600
These changes resolved the customer's connection issues and resource limitations.
Testing after changes
We conducted tests to verify the effectiveness of our changes. Here are the results:
Additional Recommendations
While the immediate issues have been resolved, we recommend the following actions to ensure long-term stability and performance:
1. Investigate root cause of connection issues
Analyze differences in connection methods between DataSync and SQLDeveloper to understand why DataSync was unable to connect initially.
2. Verify network configuration
Check firewall settings, port openings, and other network-related configurations to ensure smooth connectivity from outside the cloud.
3. Monitor resource usage
Continuously observe system performance and stability after these changes to ensure they meet the growing demands.
4. Implement backup and recovery plan
Perform regular backups, especially before and after major configuration changes, to safeguard against potential data loss.
By implementing these recommendations, you can maintain a robust and efficient Oracle database environment that meets your growing business needs.
Have you faced similar Oracle database connection issues? How did you resolve them? Share your experiences in the comments below!