x-pack/metricbeat/module/sql: Add debug queries when `merge_results: …

…true` (#42271)

(cherry picked from commit d288e54)

CHANGELOG.next.asciidoc

@@ -429,6 +429,7 @@ https://github.com/elastic/beats/compare/v8.8.1\...main[Check the HEAD diff]
 - Added `tier_preference`, `creation_date` and `version` fields to the `elasticsearch.index` metricset. {pull}41944[41944]
 - Add new OpenAI (`openai`) module for tracking usage data. {pull}41516[41516]
 - Add `use_performance_counters` to collect CPU metrics using performance counters on Windows for `system/cpu` and `system/core` {pull}41965[41965]
+- Preserve queries for debugging when `merge_results: true` in SQL module {pull}42271[42271]
 
 *Metricbeat*
 - Add benchmark module {pull}41801[41801]

x-pack/metricbeat/module/sql/query/query.go

@@ -146,7 +146,9 @@ func dbSelector(driver, dbName string) string {
 func (m *MetricSet) fetch(ctx context.Context, db *sql.DbClient, reporter mb.ReporterV2, queries []query) (bool, error) {
 	var ok bool
 	merged := make(mapstr.M, 0)
+	storeQueries := make([]string, 0, len(queries))
 	for _, q := range queries {
+		storeQueries = append(storeQueries, q.Query)
 		if q.ResponseFormat == tableResponseFormat {
 			// Table format
 			mss, err := db.FetchTableMode(ctx, q.Query)
@@ -196,7 +198,7 @@ func (m *MetricSet) fetch(ctx context.Context, db *sql.DbClient, reporter mb.Rep
 
 	if m.Config.MergeResults {
 		// Report here for merged case.
-		ok = m.reportEvent(merged, reporter, "")
+		ok = m.reportEvent(merged, reporter, storeQueries...)
 	}
 
 	return ok, nil
@@ -296,7 +298,7 @@ func (m *MetricSet) Fetch(ctx context.Context, reporter mb.ReporterV2) error {
 
 // reportEvent using 'user' mode with keys under `sql.metrics.*` or using Raw data mode (module and metricset key spaces
 // provided by the user)
-func (m *MetricSet) reportEvent(ms mapstr.M, reporter mb.ReporterV2, qry string) bool {
+func (m *MetricSet) reportEvent(ms mapstr.M, reporter mb.ReporterV2, qry ...string) bool {
 	var ok bool
 	if m.Config.RawData.Enabled {
 		// New usage.