Collector disabled on wrong PostgreSQL version due to min_version/max_version mismatch

Collectors with min_version or max_version constraints will not execute on incompatible PostgreSQL versions. For example, pg_wal_stats requires PostgreSQL 14+ (min_version: 140000) and will silently skip on older versions.

Verify PostgreSQL version with SELECT version(). Check collector version constraints in configuration files. Use pg_exporter --explain to see which collectors will execute. Adjust min_version/max_version settings or upgrade PostgreSQL if critical metrics are missing.