No data troubleshooting

Diagnosing and fixing "No data" issues in PostgresAI dashboards.

Quick checklist

1. ☐ pgwatch container is running
2. ☐ Target PostgreSQL is reachable
3. ☐ Credentials are correct
4. ☐ Required extensions are installed
5. ☐ Time range includes recent data
6. ☐ Dashboard variables are set correctly

Step-by-step diagnosis

1. Check pgwatch status

docker compose ps pgwatch

Expected: Up status

If not running:

docker compose logs pgwatch --tail 50

2. Verify PostgreSQL connectivity

# Use PGPASSWORD environment variable for authentication
docker compose exec -e PGPASSWORD="$PGPASSWORD" pgwatch psql \
  "postgresql://user@host:5432/dbname" \
  -c "select 1"

Common connection errors:

Error	Cause	Solution
could not connect to server	Network issue	Check firewall, DNS
password authentication failed	Wrong credentials	Verify username/password
no pg_hba.conf entry	pg_hba.conf missing entry	Add monitoring host to pg_hba.conf
SSL required	SSL not configured	Add ?sslmode=require to connection string

3. Check required extensions

-- Connect to target database
select * from pg_extension where extname = 'pg_stat_statements';

If missing:

create extension pg_stat_statements;

Verify it's in shared_preload_libraries:

show shared_preload_libraries;
-- Should include: pg_stat_statements

warning

Adding to shared_preload_libraries requires PostgreSQL restart.

4. Verify metrics collection

# Check pgwatch is scraping
curl http://localhost:8080/metrics | head -20

Expected: Prometheus-format metrics

# Check specific metrics
curl http://localhost:8080/metrics | grep pg_stat_statements_calls

5. Check VictoriaMetrics ingestion

curl 'http://localhost:8428/api/v1/query?query=up'

Expected:

{"status":"success","data":{"result":[...]}}

Check data for specific metric:

curl 'http://localhost:8428/api/v1/query?query=pg_stat_database_xact_commit_total'

6. Verify Grafana data source

curl http://monitor:YOUR_PASSWORD@localhost:3000/api/datasources

Check data source URL points to VictoriaMetrics.

Specific scenarios

No data for pg_stat_statements metrics

Symptoms:

• Query Analysis dashboard empty
• Single Query dashboard shows no queries

Causes and solutions:

1. Extension not installed:

   create extension pg_stat_statements;

2. Not in shared_preload_libraries:

   # postgresql.conf
   shared_preload_libraries = 'pg_stat_statements'

   Then restart PostgreSQL.

3. Insufficient track level:

   show pg_stat_statements.track;
   -- Should be 'all' or 'top'

4. Statistics were reset:

   select stats_reset from pg_stat_database where datname = current_database();

No data for specific database

Symptoms:

• Some databases show data, others don't
• Database dropdown shows the database

Causes and solutions:

1. Extension not installed in that database:

   -- Connect to specific database
   \c problematic_database
   create extension pg_stat_statements;

2. Database excluded from collection: Check pgwatch configuration for PW_EXCLUDE_DATABASES.

No data for specific cluster

Symptoms:

• Cluster dropdown shows the cluster
• All metrics for that cluster are empty

Causes and solutions:

1. Check connectivity for that specific connection:

   docker compose exec pgwatch psql "connection_string" -c "select 1"

2. Check pgwatch logs for errors:

   docker compose logs pgwatch | grep "cluster_name"

Data stops after some time

Symptoms:

• Historical data exists
• Recent data missing

Causes and solutions:

1. pgwatch crashed:

   docker compose restart pgwatch

2. Target PostgreSQL connection dropped: Check network stability and connection timeouts.

3. VictoriaMetrics storage full:

   df -h /var/lib/docker/volumes/

Dashboard-specific issues

Time range too narrow

Grafana time range may not include collected data:

• Check "Last 15 minutes" or wider
• Verify timezone settings

Wrong variable selection

Dashboard variables filter displayed data:

• Check cluster_name variable
• Check datname variable
• Try "All" option if available

Query timeout

Complex dashboards may timeout:

• Check Grafana query inspector for errors
• Increase VM_SEARCH_QUERY_TIMEOUT

Permission issues

If pgwatch can connect but gets no data:

-- Check monitoring user permissions
\du monitoring_user

-- Grant required permissions
grant pg_monitor to monitoring_user;
-- or for older PostgreSQL versions:
grant pg_read_all_stats to monitoring_user;

See Permission errors for details.

Still no data?

1. Collect diagnostic information:

   docker compose logs > monitoring-logs.txt
   docker compose ps >> monitoring-logs.txt
   curl http://localhost:8080/metrics >> monitoring-logs.txt 2>&1

2. Check GitHub Issues for similar problems

3. Open a new issue with the diagnostic output