feast-dev
diff --git a/go.mod b/go.mod
@@ -82,6 +82,10 @@ require (
 	github.com/googleapis/enterprise-certificate-proxy v0.3.7 // indirect
 	github.com/googleapis/gax-go/v2 v2.15.0 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.27.2 // indirect
+	github.com/jackc/pgpassfile v1.0.0 // indirect
+	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
+	github.com/jackc/pgx/v5 v5.8.0 // indirect
+	github.com/jackc/puddle/v2 v2.2.2 // indirect
 	github.com/klauspost/asmfmt v1.3.2 // indirect
 	github.com/klauspost/compress v1.18.0 // indirect
 	github.com/klauspost/cpuid/v2 v2.2.8 // indirect

diff --git a/go.sum b/go.sum
@@ -89,6 +89,7 @@ github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XL
 github.com/cncf/xds/go v0.0.0-20250501225837-2ac532fd4443 h1:aQ3y1lwWyqYPiWZThqv1aFbZMiM9vblcSArJRf2Irls=
 github.com/cncf/xds/go v0.0.0-20250501225837-2ac532fd4443/go.mod h1:W+zGtBO5Y1IgJhy4+A9GOqVhqLpfZi+vwmdNXUehLA8=
 github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f h1:lO4WD4F/rVNCu3HqELle0jiPLLBs70cWOduZpkS1E78=
@@ -137,6 +138,14 @@ github.com/googleapis/gax-go/v2 v2.15.0 h1:SyjDc1mGgZU5LncH8gimWo9lW1DtIfPibOG81
 github.com/googleapis/gax-go/v2 v2.15.0/go.mod h1:zVVkkxAQHa1RQpg9z2AUCMnKhi0Qld9rcmyfL1OZhoc=
 github.com/grpc-ecosystem/grpc-gateway/v2 v2.27.2 h1:8Tjv8EJ+pM1xP8mK6egEbD1OgnVTyacbefKhmbLhIhU=
 github.com/grpc-ecosystem/grpc-gateway/v2 v2.27.2/go.mod h1:pkJQ2tZHJ0aFOVEEot6oZmaVEZcRme73eIFmhiVuRWs=
+github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=
+github.com/jackc/pgpassfile v1.0.0/go.mod h1:CEx0iS5ambNFdcRtxPj5JhEz+xB6uRky5eyVu/W2HEg=
+github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 h1:iCEnooe7UlwOQYpKFhBabPMi4aNAfoODPEFNiAnClxo=
+github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761/go.mod h1:5TJZWKEWniPve33vlWYSoGYefn3gLQRzjfDlhSJ9ZKM=
+github.com/jackc/pgx/v5 v5.8.0 h1:TYPDoleBBme0xGSAX3/+NujXXtpZn9HBONkQC7IEZSo=
+github.com/jackc/pgx/v5 v5.8.0/go.mod h1:QVeDInX2m9VyzvNeiCJVjCkNFqzsNb43204HshNSZKw=
+github.com/jackc/puddle/v2 v2.2.2 h1:PR8nw+E/1w0GLuRFSmiioY6UooMp6KJv0/61nB7icHo=
+github.com/jackc/puddle/v2 v2.2.2/go.mod h1:vriiEXHvEE654aYKXXjOvZM39qJ0q+azkZFrfEOc3H4=
 github.com/klauspost/asmfmt v1.3.2 h1:4Ri7ox3EwapiOjCki+hw14RyKk201CN4rzyCJRFLpK4=
 github.com/klauspost/asmfmt v1.3.2/go.mod h1:AG8TuvYojzulgDAMCnYn50l/5QV3Bs/tp6j0HLHbNSE=
 github.com/klauspost/compress v1.18.0 h1:c/Cqfb0r+Yi+JtIEq73FWXVkRonBlf0CRNYc8Zttxdo=
@@ -165,6 +174,7 @@ github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/planetscale/vtprotobuf v0.6.1-0.20240319094008-0393e58bdf10 h1:GFCKgmp0tecUJ0sJuv4pzYCqS9+RGSn52M3FUwPs+uo=
 github.com/planetscale/vtprotobuf v0.6.1-0.20240319094008-0393e58bdf10/go.mod h1:t/avpk3KcrXxUnYOhZhMXJlSEyie6gQbtLq5NM3loB8=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/redis/go-redis/v9 v9.6.1 h1:HHDteefn6ZkTtY5fGUE8tj8uy85AHk6zP7CpzIAM0y4=
@@ -180,8 +190,11 @@ github.com/spaolacci/murmur3 v1.1.0 h1:7c1g84S4BPRrfL5Xrdp6fOJ206sU9y293DDHaoy0b
 github.com/spaolacci/murmur3 v1.1.0/go.mod h1:JwIasOWyU6f++ZhiEuf87xNszmSA2myDM2Kzu9HwQUA=
 github.com/spiffe/go-spiffe/v2 v2.5.0 h1:N2I01KCUkv1FAjZXJMwh95KK1ZIQLYbPfhaxw8WS0hE=
 github.com/spiffe/go-spiffe/v2 v2.5.0/go.mod h1:P+NxobPc6wXhVtINNtFjNWGBTreew1GBUCwT2wPmb7g=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.5.2 h1:xuMeJ0Sdp5ZMRXx/aWO6RZxdr3beISkG5/G/aIRr3pY=
 github.com/stretchr/objx v0.5.2/go.mod h1:FRsXN1f5AsAjCGJKqEizvkpNtU+EGNCLh3NxZ/8L+MA=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
 github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 github.com/zeebo/assert v1.3.0 h1:g7C04CbJuIDKNPFHmsk4hwZDO5O+kntRxzaUoNXj+IQ=
@@ -265,5 +278,6 @@ gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntN
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
@@ -66,8 +66,11 @@ func NewOnlineStore(config *registry.RepoConfig) (OnlineStore, error) {
 	} else if onlineStoreType == "dynamodb" {
 		onlineStore, err := NewDynamodbOnlineStore(config.Project, config, config.OnlineStore)
 		return onlineStore, err
+	} else if onlineStoreType == "postgres" {
+		onlineStore, err := NewPostgresOnlineStore(config.Project, config, config.OnlineStore)
+		return onlineStore, err
 	} else {
-		return nil, fmt.Errorf("%s online store type is currently not supported; only redis and sqlite are supported", onlineStoreType)
+		return nil, fmt.Errorf("%s online store type is currently not supported; only redis, sqlite, dynamodb, and postgres are supported", onlineStoreType)
 	}
 }
 

@@ -0,0 +1,197 @@
+package onlinestore
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+	"strings"
+	"time"
+
+	"github.com/feast-dev/feast/go/internal/feast/registry"
+	"github.com/feast-dev/feast/go/protos/feast/serving"
+	"github.com/feast-dev/feast/go/protos/feast/types"
+	"github.com/jackc/pgx/v5/pgxpool"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/types/known/timestamppb"
+)
+
+type PostgresOnlineStore struct {
+	project string
+	pool    *pgxpool.Pool
+	config  *registry.RepoConfig
+}
+
+func NewPostgresOnlineStore(project string, config *registry.RepoConfig, onlineStoreConfig map[string]interface{}) (*PostgresOnlineStore, error) {
+	connStr := buildPostgresConnString(onlineStoreConfig)
+	poolConfig, err := pgxpool.ParseConfig(connStr)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse postgres config: %w", err)
+	}
+
+	if schema, ok := onlineStoreConfig["db_schema"].(string); ok && schema != "" {
+		poolConfig.ConnConfig.RuntimeParams["search_path"] = schema
+	}
+
+	pool, err := pgxpool.NewWithConfig(context.Background(), poolConfig)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create postgres pool: %w", err)
+	}
+
+	return &PostgresOnlineStore{
+		project: project,
+		pool:    pool,
+		config:  config,
+	}, nil
+}
+
+func (p *PostgresOnlineStore) Destruct() {
+	if p.pool != nil {
+		p.pool.Close()
+	}
+}
+
+func (p *PostgresOnlineStore) OnlineRead(ctx context.Context, entityKeys []*types.EntityKey, featureViewNames []string, featureNames []string) ([][]FeatureData, error) {
+	featureCount := len(featureNames)
+	results := make([][]FeatureData, len(entityKeys))
+
+	serializedKeys := make([][]byte, len(entityKeys))
+	entityKeyMap := make(map[string]int, len(entityKeys))
+
+	for i, entityKey := range entityKeys {
+		serKey, err := serializeEntityKey(entityKey, p.config.EntityKeySerializationVersion)
+		if err != nil {
+			return nil, err
+		}
+		serializedKeys[i] = *serKey
+		entityKeyMap[string(*serKey)] = i
+	}
+
+	type featureRef struct {
+		name  string
+		index int
+	}
+	featuresByView := make(map[string][]featureRef)
+	for i, viewName := range featureViewNames {
+		featuresByView[viewName] = append(featuresByView[viewName], featureRef{
+			name:  featureNames[i],
+			index: i,
+		})
+	}
+
+	for viewName, features := range featuresByView {
+		featureNamesToIdx := make(map[string]int, len(features))
+		for _, f := range features {
+			featureNamesToIdx[f.name] = f.index
+		}
+
+		tableName := fmt.Sprintf(`"%s"`, strings.ReplaceAll(tableId(p.project, viewName), `"`, `""`))
+		query := fmt.Sprintf(
+			`SELECT entity_key, feature_name, value, event_ts FROM %s WHERE entity_key = ANY($1)`,
+			tableName,
+		)
+
+		rows, err := p.pool.Query(ctx, query, serializedKeys)
+		if err != nil {
+			return nil, fmt.Errorf("failed to query postgres: %w", err)
+		}
+
+		for rows.Next() {
+			var entityKeyBytes []byte
+			var featureName string
+			var valueBytes []byte
+			var eventTs time.Time
+
+			if err := rows.Scan(&entityKeyBytes, &featureName, &valueBytes, &eventTs); err != nil {
+				rows.Close()
+				return nil, fmt.Errorf("failed to scan postgres row: %w", err)
+			}
+
+			rowIdx, ok := entityKeyMap[string(entityKeyBytes)]
+			if !ok {
+				continue
+			}
+
+			if results[rowIdx] == nil {
+				results[rowIdx] = make([]FeatureData, featureCount)
+			}
+
+			if featureIdx, ok := featureNamesToIdx[featureName]; ok {
+				var value types.Value
+				if err := proto.Unmarshal(valueBytes, &value); err != nil {
+					rows.Close()
+					return nil, fmt.Errorf("failed to unmarshal feature value: %w", err)
+				}
+
+				results[rowIdx][featureIdx] = FeatureData{
+					Reference: serving.FeatureReferenceV2{FeatureViewName: viewName, FeatureName: featureName},
+					Timestamp: *timestamppb.New(eventTs),
+					Value:     types.Value{Val: value.Val},
+				}
+			}
+		}
+		rows.Close()
+		if err := rows.Err(); err != nil {
+			return nil, fmt.Errorf("error iterating postgres rows: %w", err)
+		}
+	}
+
+	return results, nil
+}
+
+func buildPostgresConnString(config map[string]interface{}) string {
+	host, _ := config["host"].(string)
+	if host == "" {
+		host = "localhost"
+	}
+
+	port := 5432
+	if p, ok := config["port"].(float64); ok {
+		port = int(p)
+	}
+
+	database, _ := config["database"].(string)
+	user, _ := config["user"].(string)
+	password, _ := config["password"].(string)
+
+	var userInfo *url.Userinfo
+	if user != "" {
+		if password != "" {
+			userInfo = url.UserPassword(user, password)
+		} else {
+			userInfo = url.User(user)
+		}
+	}
+
+	query := url.Values{}
+	if sslMode, ok := config["sslmode"].(string); ok && sslMode != "" {
+		query.Set("sslmode", sslMode)
+	} else {
+		query.Set("sslmode", "disable")
+	}
+
+	if v, ok := config["sslcert_path"].(string); ok && v != "" {
+		query.Set("sslcert", v)
+	}
+	if v, ok := config["sslkey_path"].(string); ok && v != "" {
+		query.Set("sslkey", v)
+	}
+	if v, ok := config["sslrootcert_path"].(string); ok && v != "" {
+		query.Set("sslrootcert", v)
+	}
+	if v, ok := config["min_conn"].(float64); ok {
+		query.Set("pool_min_conns", fmt.Sprintf("%d", int(v)))
+	}
+	if v, ok := config["max_conn"].(float64); ok {
+		query.Set("pool_max_conns", fmt.Sprintf("%d", int(v)))
+	}
+
+	connURL := url.URL{
+		Scheme:   "postgres",
+		User:     userInfo,
+		Host:     fmt.Sprintf("%s:%d", host, port),
+		Path:     database,
+		RawQuery: query.Encode(),
+	}
+
+	return connURL.String()
+}