- Validate CPU, RAM, storage, and IOPS match expected values. Validate CPU, RAM, storage, and IOPS match expected values. - Confirm Transparent HugePages are disabled (recommended for Oracle). Confirm Transparent HugePages are disabled (recommended for Oracle). - Verify swap configuration and file system mount options. Verify swap configuration and file system mount options.

- Ensure , , , , are correctly configured. Ensure , , , , are correctly configured. - Recheck network settings like , , . Recheck network settings like , , .

Many parameters may change when moving between versions or platforms.

- Compare old vs new values. Compare old vs new values. - Validate SGA and PGA sizing. Validate SGA and PGA sizing. - Check optimizer-related parameters: Check optimizer-related parameters: - - - - Confirm deprecated parameters are removed. Confirm deprecated parameters are removed.

- Enable Automatic Memory Management (AMM) or Automatic Shared Memory Management (ASMM) . Enable Automatic Memory Management (AMM) or Automatic Shared Memory Management (ASMM) . - Verify PGA aggregate target and SGA target values. Verify PGA aggregate target and SGA target values.

After migration, invalid objects can cause sudden performance issues. Run: And validate using:

- Ensure table, index, and column stats are updated. Ensure table, index, and column stats are updated. - Compare statistics freshness with pre-migration values. Compare statistics freshness with pre-migration values.

Execution plans may change due to a new optimizer version.

- Compare execution plans before and after migration. Compare execution plans before and after migration. - Capture SQL performance baselines. Capture SQL performance baselines. - Create SQL Plan Baselines (SPM) if needed: Create SQL Plan Baselines (SPM) if needed:

Migration can affect index usage or cause fragmentation. Checklist: - Look for unusable indexes. Look for unusable indexes. - Rebuild fragmented indexes. Rebuild fragmented indexes. - Validate bitmap, function-based, and domain indexes. Validate bitmap, function-based, and domain indexes.

After migration, track the workload closely.

- AWR Reports AWR Reports - ASH Reports ASH Reports - SQL Monitor SQL Monitor - OEM Cloud Control OEM Cloud Control

- CPU usage CPU usage - Wait events (db file sequential read, CPU wait, latch waits) Wait events (db file sequential read, CPU wait, latch waits) - I/O latencies I/O latencies - Temp usage Temp usage - Buffer cache hit ratio Buffer cache hit ratio

- Validate redo log size. Validate redo log size. - Check log switch frequency. Check log switch frequency.

- Review undo tablespace size. Review undo tablespace size. - Check for ORA-01555 snapshots. Check for ORA-01555 snapshots.

- Check temp spills. Check temp spills. - Validate size and autoextend settings. Validate size and autoextend settings.

- Check TNS, SCAN, listeners, and connection pools. Check TNS, SCAN, listeners, and connection pools. - Validate JDBC or app driver versions. Validate JDBC or app driver versions. - Test network latency between app → DB → storage. Test network latency between app → DB → storage.

- Ensure all DBMS_SCHEDULER jobs run as expected. Ensure all DBMS_SCHEDULER jobs run as expected. - Validate Data Guard sync, if used. Validate Data Guard sync, if used. - Check GoldenGate extract/replicat performance. Check GoldenGate extract/replicat performance.

Search for: - ORA-errors ORA-errors - Process restarts Process restarts - Memory pressure Memory pressure - I/O related warnings I/O related warnings

Run application-level performance tests to confirm: - Response time consistency Response time consistency - End-to-end throughput End-to-end throughput - Concurrent sessions handling Concurrent sessions handling