Precompute Aggregates in a Materialized View
Store the daily sum in a materialized view refreshed nightly so the dashboard query reads one row instead of scanning a million.
Task
Apply CREATE MATERIALIZED VIEW daily_sum AS SELECT date, SUM(amount) FROM sales GROUP BY date; to reduce a measured bottleneck that shows up in the performance budget or Lighthouse audit.
When to use this
Lighthouse reports the page fails the performance budget because of CREATE MATERIALIZED VIEW daily_sum AS SELECT date, SUM(amount) FROM sales GROUP BY date;, scoring 72 on mobile.
Prerequisites
- A Lighthouse or WebPageTest baseline measurement
- Access to the build configuration
Steps
1. Configure CREATE MATERIALIZED VIEW daily_sum AS SELECT date, SUM(amount) FROM sales GROUP BY date; in the project configuration file with the recommended defaults.
CREATE MATERIALIZED VIEW daily_sum AS SELECT date, SUM(amount) FROM sales GROUP BY date;
Expected output: The configuration is accepted and CREATE MATERIALIZED VIEW daily_sum AS SELECT date, SUM(amount) FROM sales GROUP BY date; runs without errors on the first invocation.
2. Run the check locally to verify CREATE MATERIALIZED VIEW daily_sum AS SELECT date, SUM(amount) FROM sales GROUP BY date; produces the expected result before pushing.
pnpm test
Expected output: Local run matches CI behavior; no surprises after push.
3. Add the gate to the CI pipeline so CREATE MATERIALIZED VIEW daily_sum AS SELECT date, SUM(amount) FROM sales GROUP BY date; blocks merge on failure.
- name: Run add precompute aggregate
run: pnpm test
Expected output: Pull requests with failing CREATE MATERIALIZED VIEW daily_sum AS SELECT date, SUM(amount) FROM sales GROUP BY date; are blocked from merging.
Troubleshooting
Problem
The check passes locally but fails in CI
Solution
Pin dependency versions and the runtime to match CI exactly; reproduce with the same Docker image or act.
Problem
Configuration is rejected with a schema error
Solution
Check the tool version matches the config schema; older versions may not support newer fields.
Limitations
- The gate only runs on events that trigger the workflow; locally pushed commits bypass it.
- Configuration drift is possible if someone edits settings outside version control.
Measure before optimizing
Start by measuring the problem. Store the daily sum in a materialized view refreshed nightly so the dashboard query reads one row instead of scanning a million. The most common mistake is adding the gate without first confirming it catches the issue you care about. Run CREATE MATERIALIZED VIEW daily_sum AS SELECT date, SUM(amount) FROM sales GROUP BY date; against the current codebase and inspect the output before wiring it into CI.
CREATE MATERIALIZED VIEW daily_sum AS SELECT date, SUM(amount) FROM sales GROUP BY date;Verify the improvement
Once the gate is in place, make failures actionable. A failing CREATE MATERIALIZED VIEW daily_sum AS SELECT date, SUM(amount) FROM sales GROUP BY date; should point to the exact file and line, not a generic error. Pin the tool version in the lockfile so a upstream release does not silently change behavior. Review the gate output in every pull request just like a test result.