Optimize NULL handling

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

.gitlab-ci.yml

@@ -18,6 +18,8 @@ build:
     expire_in: 1d
     reports:
       dotenv: job.env
+  rules:
+    - if: "$CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH"
 
 release:
   image: registry.gitlab.com/gitlab-org/release-cli
@@ -38,3 +40,5 @@ release:
           url: "https://git.karaolidis.com/karaolidis/telegraf-clickhouse-plugin/-/jobs/$JOB_ID/artifacts/raw/telegraf-clickhouse-plugin-linux-amd64"
         - name: "telegraf-clickhouse-plugin-linux-arm64"
           url: "https://git.karaolidis.com/karaolidis/telegraf-clickhouse-plugin/-/jobs/$JOB_ID/artifacts/raw/telegraf-clickhouse-plugin-linux-arm64"
+  rules:
+    - if: "$CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH"

plugins/outputs/clickhouse/clickhouse.go

@@ -158,11 +158,12 @@ func (ch *ClickHouse) toDatatype(value interface{}) string {
 	return datatype
 }
 
-func (ch *ClickHouse) toNullable(pair *orderedmap.Pair[string, string]) string {
+func (ch *ClickHouse) toNullableDatatype(key string, value interface{}) string {
-	if pair.Key != "host" && pair.Key != ch.TimestampColumn && pair.Key != "measurement" {
+	datatype := ch.toDatatype(value)
-		return fmt.Sprintf("Nullable(%s)", pair.Value)
+	if key != "host" && key != ch.TimestampColumn && key != "measurement" {
+		return fmt.Sprintf("Nullable(%s)", datatype)
 	}
-	return pair.Value
+	return datatype
 }
 
 func (ch *ClickHouse) pepareMetrics(metrics []telegraf.Metric, metricsData map[string][]map[string]interface{}, columns map[string]*orderedmap.OrderedMap[string, string]) {
@@ -188,12 +189,12 @@ func (ch *ClickHouse) pepareMetrics(metrics []telegraf.Metric, metricsData map[s
 
 		for _, tag := range metric.TagList() {
 			metricEntry[tag.Key] = tag.Value
-			columns[tablename].Set(tag.Key, ch.toDatatype(tag.Value))
+			columns[tablename].Set(tag.Key, ch.toNullableDatatype(tag.Key, tag.Value))
 		}
 
 		for _, field := range metric.FieldList() {
 			metricEntry[field.Key] = field.Value
-			columns[tablename].Set(field.Key, ch.toDatatype(field.Value))
+			columns[tablename].Set(field.Key, ch.toNullableDatatype(field.Key, field.Value))
 		}
 
 		metricsData[tablename] = append(metricsData[tablename], metricEntry)
@@ -203,10 +204,10 @@ func (ch *ClickHouse) pepareMetrics(metrics []telegraf.Metric, metricsData map[s
 func (ch *ClickHouse) generateCreateTable(tablename string, columns *orderedmap.OrderedMap[string, string]) string {
 	columnDefs := make([]string, 0, columns.Len())
 	for pair := columns.Oldest(); pair != nil; pair = pair.Next() {
-		columnDefs = append(columnDefs, fmt.Sprintf("%s %s", quoteIdent(pair.Key), ch.toNullable(pair)))
+		columnDefs = append(columnDefs, fmt.Sprintf("%s %s", quoteIdent(pair.Key), pair.Value))
 	}
 
-	orderBy := make([]string, 0, 3)
+	orderBy := make([]string, 0, 2)
 	if _, ok := columns.Get("host"); ok {
 		orderBy = append(orderBy, "host")
 	}
@@ -230,15 +231,14 @@ func (ch *ClickHouse) generateAlterTable(tablename string, columns *orderedmap.O
 	modifyDefs := make([]string, 0, columns.Len())
 
 	for pair := columns.Oldest(); pair != nil; pair = pair.Next() {
-		columnType := ch.toNullable(pair)
 
 		alterDefs = append(alterDefs, fmt.Sprintf("ADD COLUMN IF NOT EXISTS %s %s",
 			quoteIdent(pair.Key),
-			columnType))
+			pair.Value))
 
 		modifyDefs = append(modifyDefs, fmt.Sprintf("MODIFY COLUMN IF EXISTS %s %s",
 			quoteIdent(pair.Key),
-			columnType))
+			pair.Value))
 	}
 
 	return fmt.Sprintf("ALTER TABLE %s %s, %s",
@@ -286,7 +286,7 @@ func (ch *ClickHouse) ensureTable(tablename string, columns *orderedmap.OrderedM
 	}
 
 	for pair := columns.Oldest(); pair != nil; pair = pair.Next() {
-		if _, ok := tableColumns[pair.Key]; !ok || tableColumns[pair.Key] != ch.toNullable(pair) {
+		if _, ok := tableColumns[pair.Key]; !ok || tableColumns[pair.Key] != pair.Value {
 			_, err = ch.db.Exec(ch.generateAlterTable(tablename, columns))
 			if err != nil {
 				return err