feat(outputs.postgresql): Add option to rename time column (#13750)

plugins/outputs/postgresql/README.md

@@ -54,6 +54,10 @@ See the [CONFIGURATION.md][CONFIGURATION.md] for more details.
   ## Store all fields as a JSONB object in a single 'fields' column.
   # fields_as_jsonb = false
 
+  ## Name of the timestamp column
+  ## NOTE: Some tools (e.g. Grafana) require the default name so be careful!
+  # timestamp_column_name = "time"
+
   ## Templated statements to execute when creating a new table.
   # create_templates = [
   #   '''CREATE TABLE {{ .table }} ({{ .columns }})''',

plugins/outputs/postgresql/columns.go

@@ -2,22 +2,6 @@ package postgresql
 
 import "github.com/influxdata/telegraf/plugins/outputs/postgresql/utils"
 
-// Column names and data types for standard fields (time, tag_id, tags, and fields)
-const (
-	timeColumnName       = "time"
-	timeColumnDataType   = PgTimestampWithoutTimeZone
-	tagIDColumnName      = "tag_id"
-	tagIDColumnDataType  = PgBigInt
-	tagsJSONColumnName   = "tags"
-	fieldsJSONColumnName = "fields"
-	jsonColumnDataType   = PgJSONb
-)
-
-var timeColumn = utils.Column{Name: timeColumnName, Type: timeColumnDataType, Role: utils.TimeColType}
-var tagIDColumn = utils.Column{Name: tagIDColumnName, Type: tagIDColumnDataType, Role: utils.TagsIDColType}
-var fieldsJSONColumn = utils.Column{Name: fieldsJSONColumnName, Type: jsonColumnDataType, Role: utils.FieldColType}
-var tagsJSONColumn = utils.Column{Name: tagsJSONColumnName, Type: jsonColumnDataType, Role: utils.TagColType}
-
 func (p *Postgresql) columnFromTag(key string, value interface{}) utils.Column {
 	return utils.Column{Name: key, Type: p.derivePgDatatype(value), Role: utils.TagColType}
 }

plugins/outputs/postgresql/postgresql.go

@@ -41,6 +41,7 @@ type Postgresql struct {
 	ForeignTagConstraint       bool                    `toml:"foreign_tag_constraint"`
 	TagsAsJsonb                bool                    `toml:"tags_as_jsonb"`
 	FieldsAsJsonb              bool                    `toml:"fields_as_jsonb"`
+	TimestampColumnName        string                  `toml:"timestamp_column_name"`
 	CreateTemplates            []*sqltemplate.Template `toml:"create_templates"`
 	AddColumnTemplates         []*sqltemplate.Template `toml:"add_column_templates"`
 	TagTableCreateTemplates    []*sqltemplate.Template `toml:"tag_table_create_templates"`
@@ -49,6 +50,7 @@ type Postgresql struct {
 	RetryMaxBackoff            config.Duration         `toml:"retry_max_backoff"`
 	TagCacheSize               int                     `toml:"tag_cache_size"`
 	LogLevel                   string                  `toml:"log_level"`
+	Logger                     telegraf.Logger         `toml:"-"`
 
 	dbContext       context.Context
 	dbContextCancel func()
@@ -62,7 +64,11 @@ type Postgresql struct {
 	writeChan      chan *TableSource
 	writeWaitGroup *utils.WaitGroup
 
-	Logger telegraf.Logger `toml:"-"`
+	// Column types
+	timeColumn       utils.Column
+	tagIDColumn      utils.Column
+	fieldsJSONColumn utils.Column
+	tagsJSONColumn   utils.Column
 }
 
 func init() {
@@ -99,6 +105,21 @@ func (p *Postgresql) Init() error {
 		return fmt.Errorf("invalid tag_cache_size")
 	}
 
+	// Set the time-column name
+	if p.TimestampColumnName == "" {
+		p.TimestampColumnName = "time"
+	}
+
+	// Initialize the column prototypes
+	p.timeColumn = utils.Column{
+		Name: p.TimestampColumnName,
+		Type: PgTimestampWithoutTimeZone,
+		Role: utils.TimeColType,
+	}
+	p.tagIDColumn = utils.Column{Name: "tag_id", Type: PgBigInt, Role: utils.TagsIDColType}
+	p.fieldsJSONColumn = utils.Column{Name: "fields", Type: PgJSONb, Role: utils.FieldColType}
+	p.tagsJSONColumn = utils.Column{Name: "tags", Type: PgJSONb, Role: utils.TagColType}
+
 	var err error
 	if p.dbConfig, err = pgxpool.ParseConfig(p.Connection); err != nil {
 		return err

plugins/outputs/postgresql/postgresql_test.go

@@ -17,6 +17,7 @@ import (
 	"github.com/testcontainers/testcontainers-go/wait"
 
 	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/metric"
 	"github.com/influxdata/telegraf/plugins/outputs/postgresql/utils"
 	"github.com/influxdata/telegraf/testutil"
 )
@@ -588,6 +589,39 @@ func TestWriteIntegration_concurrentTempError(t *testing.T) {
 	require.True(t, haveError, "write error not found in log")
 }
 
+func TestTimestampColumnNameIntegration(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping integration test in short mode")
+	}
+
+	p := newPostgresqlTest(t)
+	p.TimestampColumnName = "timestamp"
+	require.NoError(t, p.Init())
+	require.NoError(t, p.Connect())
+
+	metrics := []telegraf.Metric{
+		metric.New(t.Name(), map[string]string{}, map[string]interface{}{"v": 42}, time.Unix(1691747345, 0)),
+	}
+	require.NoError(t, p.Write(metrics))
+
+	dump := dbTableDump(t, p.db, "")
+	require.Len(t, dump, 1)
+	require.EqualValues(t, 42, dump[0]["v"])
+	require.EqualValues(t, time.Unix(1691747345, 0).UTC(), dump[0]["timestamp"])
+	require.NotContains(t, dump[0], "time")
+
+	p.Logger.Clear()
+	require.NoError(t, p.Write(metrics))
+
+	stmtCount := 0
+	for _, log := range p.Logger.Logs() {
+		if strings.Contains(log.String(), "info: PG ") {
+			stmtCount++
+		}
+	}
+	require.Equal(t, 3, stmtCount) // BEGIN, COPY metrics table, COMMIT
+}
+
 func TestWriteTagTableIntegration(t *testing.T) {
 	if testing.Short() {
 		t.Skip("Skipping integration test in short mode")

plugins/outputs/postgresql/sample.conf

@@ -37,6 +37,10 @@
   ## Store all fields as a JSONB object in a single 'fields' column.
   # fields_as_jsonb = false
 
+  ## Name of the timestamp column
+  ## NOTE: Some tools (e.g. Grafana) require the default name so be careful!
+  # timestamp_column_name = "time"
+
   ## Templated statements to execute when creating a new table.
   # create_templates = [
   #   '''CREATE TABLE {{ .table }} ({{ .columns }})''',

plugins/outputs/postgresql/table_manager.go

@@ -318,16 +318,17 @@ func (tm *TableManager) getColumns(ctx context.Context, db dbh, name string) (ma
 
 		role := utils.FieldColType
 		switch colName {
-		case timeColumnName:
+		case tm.timeColumn.Name:
 			role = utils.TimeColType
-		case tagIDColumnName:
+		case tm.tagIDColumn.Name:
 			role = utils.TagsIDColType
-		case tagsJSONColumnName:
+		case tm.tagsJSONColumn.Name:
 			role = utils.TagColType
-		case fieldsJSONColumnName:
+		case tm.fieldsJSONColumn.Name:
 			role = utils.FieldColType
 		default:
-			// We don't want to monopolize the column comment (preventing user from storing other information there), so just look at the first word
+			// We don't want to monopolize the column comment (preventing user from storing other information there),
+			// so just look at the first word
 			if desc != nil {
 				descWords := strings.Split(*desc, " ")
 				if descWords[0] == "tag" {

plugins/outputs/postgresql/table_source.go

@@ -133,7 +133,7 @@ func (tsrc *TableSource) TagColumns() []utils.Column {
 	var cols []utils.Column
 
 	if tsrc.postgresql.TagsAsJsonb {
-		cols = append(cols, tagsJSONColumn)
+		cols = append(cols, tsrc.postgresql.tagsJSONColumn)
 	} else {
 		cols = append(cols, tsrc.tagColumns.columns...)
 	}
@@ -149,17 +149,17 @@ func (tsrc *TableSource) FieldColumns() []utils.Column {
 // MetricTableColumns returns the full column list, including time, tag id or tags, and fields.
 func (tsrc *TableSource) MetricTableColumns() []utils.Column {
 	cols := []utils.Column{
-		timeColumn,
+		tsrc.postgresql.timeColumn,
 	}
 
 	if tsrc.postgresql.TagsAsForeignKeys {
-		cols = append(cols, tagIDColumn)
+		cols = append(cols, tsrc.postgresql.tagIDColumn)
 	} else {
 		cols = append(cols, tsrc.TagColumns()...)
 	}
 
 	if tsrc.postgresql.FieldsAsJsonb {
-		cols = append(cols, fieldsJSONColumn)
+		cols = append(cols, tsrc.postgresql.fieldsJSONColumn)
 	} else {
 		cols = append(cols, tsrc.FieldColumns()...)
 	}
@@ -169,7 +169,7 @@ func (tsrc *TableSource) MetricTableColumns() []utils.Column {
 
 func (tsrc *TableSource) TagTableColumns() []utils.Column {
 	cols := []utils.Column{
-		tagIDColumn,
+		tsrc.postgresql.tagIDColumn,
 	}
 
 	cols = append(cols, tsrc.TagColumns()...)