Add disk blocks read per second

app/services/metrics/metrics.go

@@ -144,6 +144,7 @@ func (mp *metricspusher) Push(cred credential.Credential) error {
 		ReplicationLagSeconds: dbMetrics.ReplicationLagSeconds,
 		CacheHitRatio:         dbMetrics.CacheHitRatio,
 		TransactionsPerSecond: dbMetrics.TransactionsPerSecond,
+		BlocksReadPerSecond:   dbMetrics.BlocksReadPerSecond,
 	}
 
 	return mp.apiserver.PushPostgreSQLMetrics(ctx, combined, agentID)

domain/metrics/metrics.go

@@ -14,4 +14,5 @@ type PostgreSQLMetrics struct {
 	ReplicationLagSeconds int     `json:"replication_lag_seconds"`
 	CacheHitRatio         float64 `json:"cache_hit_ratio"`
 	TransactionsPerSecond float64 `json:"transactions_per_second"`
+	BlocksReadPerSecond   float64 `json:"blocks_read_per_second"`
 }

internal/pgmetrics/collector.go

@@ -16,6 +16,7 @@ type DatabaseMetrics struct {
 	MaxConnections        int
 	CacheHitRatio         float64
 	TransactionsPerSecond float64
+	BlocksReadPerSecond   float64
 	ReplicationLagSeconds int
 }
 
@@ -113,6 +114,20 @@ func (pgm pgmetrics) collectDatabaseMetrics(ctx context.Context, db *sql.DB, m *
 		m.TransactionsPerSecond = 0
 	}
 
+	// Blocks read per second
+	blocksQuery := `
+		SELECT
+			COALESCE(ROUND(
+				sum(blks_read)::numeric /
+				NULLIF(EXTRACT(EPOCH FROM (now() - min(stats_reset))), 0)
+			, 2), 0) as blocks_read_per_sec
+		FROM pg_stat_database
+		WHERE stats_reset IS NOT NULL;
+	`
+	if err := db.QueryRowContext(ctx, blocksQuery).Scan(&m.BlocksReadPerSecond); err != nil {
+		m.BlocksReadPerSecond = 0
+	}
+
 	return nil
 }
 

internal/pgmetrics/collector_test.go

@@ -109,17 +109,21 @@ func TestCollector_Collect(t *testing.T) {
 	// Verify connections are being tracked
 	assert.GreaterOrEqual(t, metrics.ConnectionsTotal, 1, "should have at least 1 connection")
 
+	// Verify max connections is set (default is typically 100)
+	assert.Greater(t, metrics.MaxConnections, 0, "max_connections should be greater than 0")
+
 	// Verify cache hit ratio is calculated (should be between 0 and 100)
 	assert.GreaterOrEqual(t, metrics.CacheHitRatio, 0.0)
 	assert.LessOrEqual(t, metrics.CacheHitRatio, 100.0)
 
 	// TPS might be 0 for a new database without stats_reset or very low activity
 	assert.GreaterOrEqual(t, metrics.TransactionsPerSecond, 0.0)
 
+	// Blocks read per second might be 0 for a new database without stats_reset
+	assert.GreaterOrEqual(t, metrics.BlocksReadPerSecond, 0.0)
+
 	// Replication lag should be 0 when no replication is configured
 	assert.Equal(t, 0, metrics.ReplicationLagSeconds)
-
-	t.Logf("Collected metrics: %+v", metrics)
 }
 
 func TestCollector_Collect_InvalidCredentials(t *testing.T) {
@@ -154,8 +158,6 @@ func TestCollector_Collect_CacheHitRatio(t *testing.T) {
 	// It should be high since we're reading the same data multiple times
 	assert.Greater(t, metrics.CacheHitRatio, 0.0,
 		"cache hit ratio should be greater than 0 after queries")
-
-	t.Logf("Cache hit ratio: %.2f%%", metrics.CacheHitRatio)
 }
 
 func TestCollector_Collect_Timeout(t *testing.T) {