feat: Optimize Postgres Event Reading schema

[weichou1229]

Optimize Postgres Event Reading schema to reduce disk usage.

Closes #5088

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[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
1 Security Hotspot
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud