feat: Store numeric value in numeric type (#5232)

To improve disk consumption by storing numeric values rather than strings.

Closes #5231

Signed-off-by: bruce <[email protected]>

Author: weichou1229

internal/core/data/embed/sql/versions/4.1.0-dev/00-tables.sql

@@ -7,3 +7,5 @@ ALTER TABLE core_data.device_info ADD COLUMN IF NOT EXISTS mark_deleted BOOLEAN
 
 -- create index on reading(event_id) to enhance the query performance
 CREATE INDEX IF NOT EXISTS idx_reading_event_id ON core_data.reading(event_id);
+
+ALTER TABLE core_data.reading ADD COLUMN IF NOT EXISTS numeric_value NUMERIC;

internal/pkg/infrastructure/postgres/consts.go

@@ -68,6 +68,7 @@ const (
 	eventIdFKCol      = "event_id"
 	deviceInfoIdFKCol = "device_info_id"
 	valueCol          = "value"
+	numericValueCol   = "numeric_value"
 	binaryValueCol    = "binaryvalue"
 	mediaTypeCol      = "mediatype"
 	objectValueCol    = "objectvalue"

internal/pkg/infrastructure/postgres/models/reading.go

@@ -1,11 +1,15 @@
 //
-// Copyright (C) 2024 IOTech Ltd
+// Copyright (C) 2024-2025 IOTech Ltd
 //
 // SPDX-License-Identifier: Apache-2.0
 
 package models
 
-import "github.com/edgexfoundry/go-mod-core-contracts/v4/models"
+import (
+	"github.com/jackc/pgx/v5/pgtype"
+
+	"github.com/edgexfoundry/go-mod-core-contracts/v4/models"
+)
 
 // Reading struct contains the columns of the core_data.reading table in Postgres db relates to a reading
 // which includes all the fields in BaseReading, BinaryReading, SimpleReading and ObjectReading
@@ -18,7 +22,8 @@ type Reading struct {
 }
 
 type SimpleReading struct {
-	Value *string
+	Value        *string
+	NumericValue *pgtype.Numeric
 }
 
 type BinaryReading struct {

internal/pkg/infrastructure/postgres/reading.go

@@ -9,21 +9,24 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"strconv"
 	"strings"
 
 	pgClient "github.com/edgexfoundry/edgex-go/internal/pkg/db/postgres"
 	dbModels "github.com/edgexfoundry/edgex-go/internal/pkg/infrastructure/postgres/models"
+	"github.com/edgexfoundry/go-mod-core-contracts/v4/common"
 	"github.com/edgexfoundry/go-mod-core-contracts/v4/errors"
 	model "github.com/edgexfoundry/go-mod-core-contracts/v4/models"
 
 	"github.com/google/uuid"
 	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgtype"
 	"github.com/jackc/pgx/v5/pgxpool"
 )
 
 var (
 	// insertReadingCols defines the reading table columns in slice used in inserting readings
-	insertReadingCols = []string{eventIdFKCol, deviceInfoIdFKCol, originCol, valueCol, binaryValueCol, objectValueCol}
+	insertReadingCols = []string{eventIdFKCol, deviceInfoIdFKCol, originCol, valueCol, numericValueCol, binaryValueCol, objectValueCol}
 )
 
 func (c *Client) ReadingTotalCount() (uint32, errors.EdgeX) {
@@ -279,6 +282,33 @@ func queryReadings(ctx context.Context, connPool *pgxpool.Pool, sql string, args
 				Value:       *readingDBModel.Value,
 			}
 			reading = simpleReading
+		} else if readingDBModel.NumericValue != nil {
+			// reading type is numeric SimpleReading
+			var val string
+			switch baseReading.ValueType {
+			case common.ValueTypeFloat32:
+				numericVal, err := readingDBModel.NumericValue.Float64Value()
+				if err != nil {
+					return nil, pgClient.WrapDBError("failed to read the float value", err)
+				}
+				val = strconv.FormatFloat(numericVal.Float64, 'e', -1, 32)
+			case common.ValueTypeFloat64:
+				numericVal, err := readingDBModel.NumericValue.Float64Value()
+				if err != nil {
+					return nil, pgClient.WrapDBError("failed to read the float value", err)
+				}
+				val = strconv.FormatFloat(numericVal.Float64, 'e', -1, 64)
+			default:
+				numericVal, err := readingDBModel.NumericValue.Value() // NumericValue.Value() return value in string
+				if err != nil {
+					return nil, pgClient.WrapDBError("failed to read the float value", err)
+				}
+				val = fmt.Sprintf("%v", numericVal)
+			}
+			reading = model.SimpleReading{
+				BaseReading: baseReading,
+				Value:       val,
+			}
 		} else {
 			// reading type is NullReading
 			nullReading := model.NullReading{
@@ -373,8 +403,30 @@ func (c *Client) addReadingsInTx(tx pgx.Tx, readings []model.Reading, eventId st
 		case model.SimpleReading:
 			// convert SimpleReading struct to Reading DB model
 			readingDBModel = dbModels.Reading{
-				BaseReading:   baseReading,
-				SimpleReading: dbModels.SimpleReading{Value: &contractReadingModel.Value},
+				BaseReading: baseReading,
+			}
+			switch contractReadingModel.ValueType {
+			case common.ValueTypeFloat32:
+				var numericVal pgtype.Numeric
+				if err := numericVal.ScanScientific(contractReadingModel.Value); err != nil {
+					return errors.NewCommonEdgeX(errors.KindContractInvalid, fmt.Sprintf("invalid numeric value '%s'", contractReadingModel.Value), err)
+				}
+				readingDBModel.SimpleReading = dbModels.SimpleReading{NumericValue: &numericVal}
+			case common.ValueTypeFloat64:
+				var numericVal pgtype.Numeric
+				if err := numericVal.ScanScientific(contractReadingModel.Value); err != nil {
+					return errors.NewCommonEdgeX(errors.KindContractInvalid, fmt.Sprintf("invalid numeric value '%s'", contractReadingModel.Value), err)
+				}
+				readingDBModel.SimpleReading = dbModels.SimpleReading{NumericValue: &numericVal}
+			case common.ValueTypeUint8, common.ValueTypeUint16, common.ValueTypeUint32, common.ValueTypeUint64,
+				common.ValueTypeInt8, common.ValueTypeInt16, common.ValueTypeInt32, common.ValueTypeInt64:
+				var val pgtype.Numeric
+				if err := val.Scan(contractReadingModel.Value); err != nil {
+					return errors.NewCommonEdgeX(errors.KindContractInvalid, fmt.Sprintf("invalid numeric value '%s'", contractReadingModel.Value), err)
+				}
+				readingDBModel.SimpleReading = dbModels.SimpleReading{NumericValue: &val}
+			default:
+				readingDBModel.SimpleReading = dbModels.SimpleReading{Value: &contractReadingModel.Value}
 			}
 		case model.NullReading:
 			readingDBModel = dbModels.Reading{
@@ -413,6 +465,7 @@ func (c *Client) addReadingsInTx(tx pgx.Tx, readings []model.Reading, eventId st
 				deviceInfoId,
 				r.Origin,
 				r.Value,
+				r.NumericValue,
 				r.BinaryValue,
 				objectValueBytes,
 			}, nil

internal/pkg/infrastructure/postgres/sql.go

@@ -16,7 +16,7 @@ import (
 
 const (
 	eventColumns   = "event.id, devicename, profilename, sourcename, origin, tags"
-	readingColumns = "event_id, origin, value, binaryvalue, objectvalue, devicename, profilename, resourcename, valuetype, units, mediatype, tags"
+	readingColumns = "event_id, origin, value, numeric_value, binaryvalue, objectvalue, devicename, profilename, resourcename, valuetype, units, mediatype, tags"
 )
 
 // ----------------------------------------------------------------------------------