Remove TODO/Update MariaDB compatibility

pkg/rdbms/mysql/diagnostics/collectorBuffer.go

@@ -1,21 +1,19 @@
 package diagnostics
 
 import (
+	"fmt"
 	"database/sql"
 )
 
-const BufferCacheQuery string = `
+const BufferCacheQueryTpl string = `
 SELECT
    ROUND(
 		(SUM(IF(variable_name='Innodb_buffer_pool_read_requests', variable_value,  0))
 		/ (SUM(IF(variable_name IN ('Innodb_buffer_pool_read_requests', 'Innodb_buffer_pool_reads'), variable_value, 0)))
 	) * 100, 2) AS buffer_pool_hit_ratio_pct
-FROM performance_schema.global_status;
+FROM %s
 `
 
-// FROM information_schema.GLOBAL_STATUS; // MariaDB
-// FROM performance_schema.global_status; // MySQL;
-
 type DatabaseBufferStat struct {
 	BufferPoolHitRatio float64
 }
@@ -31,12 +29,25 @@ func NewDatabaseBufferCollector(db *sql.DB) *DatabaseBufferCollector {
 }
 
 func (b *DatabaseBufferCollector) Collect() (DatabaseBufferStat, error) {
-	var hitRatio float64
-	err := b.DB.QueryRow(BufferCacheQuery).Scan(&hitRatio)
-	if err != nil {
-		return DatabaseBufferStat{}, err
+	var fromCandidates = []string{
+		"performance_schema.global_status", // MySQL
+		"information_schema.GLOBAL_STATUS", // MariaDB
 	}
+    var stat DatabaseBufferStat
+    var lastErr error
+
+    for _, from := range fromCandidates {
+        query := fmt.Sprintf(BufferCacheQueryTpl, from)
+
+        var hitRatio float64
+        err := b.DB.QueryRow(query).Scan(&hitRatio)
+        if err == nil {
+            stat.BufferPoolHitRatio = hitRatio
+            return stat, nil
+        }
+
+        lastErr = fmt.Errorf("buffer cache query failed on %s: %w", from, err)
+    }
 
-	stat := DatabaseBufferStat{BufferPoolHitRatio: hitRatio}
-	return stat, nil
+    return DatabaseBufferStat{}, lastErr
 }

pkg/rdbms/mysql/diagnostics/collectorThread.go

@@ -1,18 +1,18 @@
 package diagnostics
 
-import "database/sql"
+import (
+	"fmt"
+	"database/sql"
+)
 
-const ThreadQuery string = `
+const ThreadQueryTpl = `
 SELECT
     MAX(CASE WHEN VARIABLE_NAME = 'Threads_connected' THEN VARIABLE_VALUE END) AS threads_connected,
     MAX(CASE WHEN VARIABLE_NAME = 'Threads_running'   THEN VARIABLE_VALUE END) AS threads_running
- FROM performance_schema.global_status
+FROM %s
 WHERE VARIABLE_NAME IN ('Threads_connected', 'Threads_running');
 `
 
-// FROM information_schema.GLOBAL_STATUS; // MariaDB
-// FROM performance_schema.global_status; // MySQL;
-
 type DatabaseThreadStat struct {
 	ThreadConnected int64
 	ThreadRunning   int64
@@ -29,11 +29,26 @@ func NewDatabaseThreadCollector(db *sql.DB) *DatabaseThreadCollector {
 }
 
 func (b *DatabaseThreadCollector) Collect() (DatabaseThreadStat, error) {
-	var threadStat DatabaseThreadStat
-	err := b.DB.QueryRow(ThreadQuery).Scan(&threadStat.ThreadConnected, &threadStat.ThreadRunning)
-	if err != nil {
-		return DatabaseThreadStat{}, err
+	var fromCandidates = []string{
+		"performance_schema.global_status", // MySQL
+		"information_schema.GLOBAL_STATUS", // MariaDB
 	}
+    var threadStat DatabaseThreadStat
+    var lastErr error
+
+    for _, from := range fromCandidates {
+        query := fmt.Sprintf(ThreadQueryTpl, from)
+
+        err := b.DB.QueryRow(query).Scan(&threadStat.ThreadConnected, &threadStat.ThreadRunning)
+        if err == nil {
+            // 성공
+            return threadStat, nil
+        }
+
+        // 실패하면 다음 candidate 시도
+        lastErr = fmt.Errorf("query failed on %s: %w", from, err)
+    }
 
-	return threadStat, nil
+    // 모든 candidate 실패 시 에러 반환
+    return DatabaseThreadStat{}, lastErr
 }

pkg/rdbms/mysql/diagnostics/collectorWorkload.go

@@ -14,7 +14,7 @@ SELECT
     SUM(SUM_TIMER_WAIT)     AS total_latency_ps,
     MAX(MAX_TIMER_WAIT)     AS max_latency_ps
  FROM performance_schema.events_statements_summary_by_digest
-WHERE OBJECT_SCHEMA = ?
+WHERE SCHEMA_NAME = ?
   AND DIGEST_TEXT NOT LIKE 'COMMIT%'
   AND DIGEST_TEXT NOT LIKE 'ROLLBACK%'
   AND DIGEST_TEXT NOT LIKE 'START TRANSACTION%'

websrc/controllers/healthCheckHandlers.go

@@ -49,7 +49,6 @@ func (h *HealthHandler) GetSystemReadyHandler(ctx echo.Context) error {
 	start := time.Now()
 	logger, logstrings := pageLogInit(ctx, "healthcheck-task", "Ready?", start)
 
-	// TODO - db 헬스체크 추가 예정
 	dbHealthy := h.isDatabaseHealthy()
 	if !dbHealthy {
 		errStr := "db is not healthy"