diff --git a/internal/database/database.go b/internal/database/database.go
index 0a28b614e..d4e3336c1 100644
--- a/internal/database/database.go
+++ b/internal/database/database.go
@@ -11,6 +11,8 @@ import (
 	_ "github.com/lib/pq"
 )
 
+type RowMap = map[string]interface{}
+
 type DB struct {
 	*sqlx.DB
 }
diff --git a/internal/database/export.go b/internal/database/export.go
deleted file mode 100644
index 1ba17d426..000000000
--- a/internal/database/export.go
+++ /dev/null
@@ -1,56 +0,0 @@
-package database
-
-import (
-	"context"
-	"fmt"
-	"math/rand"
-	"strings"
-
-	"github.com/onestore-ai/onestore/pkg/onestore/types"
-)
-
-func (db *DB) createTableEntityDfWithFeatures(ctx context.Context, features []*types.RichFeature, entity *types.Entity) (string, error) {
-	tableName := fmt.Sprintf("entity_df_with_features_%d", rand.Int())
-	schema := `
-		CREATE TABLE %s (
-			unique_key  VARCHAR(%d) NOT NULL,
-			entity_key  VARCHAR(%d) NOT NULL,
-			unix_time   BIGINT NOT NULL,
-			%s,
-			PRIMARY KEY (entity_key, unix_time)
-		);
-	`
-
-	var columnDefs []string
-	for _, f := range features {
-		columnDefs = append(columnDefs, fmt.Sprintf(`"%s" %s`, f.Name, f.ValueType))
-	}
-	// unique_key = entity_key,unix_time; length of unique_key = entity.Length + 9
-	schema = fmt.Sprintf(schema, tableName, entity.Length+10, entity.Length, strings.Join(columnDefs, ",\n"))
-	_, err := db.ExecContext(ctx, schema)
-	return tableName, err
-}
-
-func (db *DB) createAndImportTableEntityDf(ctx context.Context, entityRows []types.EntityRow, entity *types.Entity) (string, error) {
-	tableName := fmt.Sprintf("entity_df_%d", rand.Int())
-	schema := fmt.Sprintf(`
-		CREATE TABLE %s (
-			entity_key  VARCHAR(%d) NOT NULL,
-			unix_time   BIGINT NOT NULL,
-			PRIMARY KEY (entity_key, unix_time)
-		);
-	`, tableName, entity.Length)
-	if _, err := db.ExecContext(ctx, schema); err != nil {
-		return tableName, err
-	}
-
-	insertQuery := fmt.Sprintf(`INSERT INTO %s(entity_key, unix_time) VALUES (:entity_key, :unix_time)`, tableName)
-	_, err := db.NamedExec(insertQuery, entityRows)
-	return tableName, err
-}
-
-func (db *DB) dropTable(ctx context.Context, tableName string) error {
-	query := fmt.Sprintf(`DROP TABLE IF EXISTS %s;`, tableName)
-	_, err := db.ExecContext(ctx, query)
-	return err
-}
diff --git a/internal/database/feature_value.go b/internal/database/feature_value.go
deleted file mode 100644
index 08a6e727f..000000000
--- a/internal/database/feature_value.go
+++ /dev/null
@@ -1,97 +0,0 @@
-package database
-
-import (
-	"context"
-	"fmt"
-	"strings"
-
-	"github.com/jmoiron/sqlx"
-	"github.com/onestore-ai/onestore/pkg/onestore/types"
-	"github.com/spf13/cast"
-)
-
-type RowMap = map[string]interface{}
-
-func getFeatureValueMapFromRows(rows *sqlx.Rows, entityName string) (map[string]RowMap, error) {
-	featureValueMap := make(map[string]RowMap)
-	for rows.Next() {
-		rowMap := make(RowMap)
-		if err := rows.MapScan(rowMap); err != nil {
-			return nil, err
-		}
-		entityKey, ok := rowMap[entityName]
-		if !ok {
-			return nil, fmt.Errorf("missing column %s", entityName)
-		}
-		delete(rowMap, entityName)
-		featureValueMap[cast.ToString(entityKey)] = rowMap
-	}
-	return featureValueMap, nil
-}
-
-func (db *DB) GetPointInTimeFeatureValues(ctx context.Context, entity *types.Entity, revisionRanges []*types.RevisionRange, features []*types.RichFeature, entityRows []types.EntityRow) (dataMap map[string]RowMap, err error) {
-	if len(features) == 0 {
-		return make(map[string]RowMap), nil
-	}
-
-	// Step 0: prepare temporary tables
-	entityDfWithFeatureName, tmpErr := db.createTableEntityDfWithFeatures(ctx, features, entity)
-	if tmpErr != nil {
-		return nil, tmpErr
-	}
-	defer func() {
-		if tmpErr := db.dropTable(ctx, entityDfWithFeatureName); tmpErr != nil {
-			err = tmpErr
-		}
-	}()
-
-	entityDfName, tmpErr := db.createAndImportTableEntityDf(ctx, entityRows, entity)
-	if tmpErr != nil {
-		return nil, tmpErr
-	}
-	defer func() {
-		if tmpErr := db.dropTable(ctx, entityDfName); tmpErr != nil {
-			err = tmpErr
-		}
-	}()
-
-	// Step 1: iterate each table range, get result
-	joinQuery := `
-		INSERT INTO %s(unique_key, entity_key, unix_time, %s)
-		SELECT
-			CONCAT(l.entity_key, ',', l.unix_time) AS unique_key,
-			l.entity_key AS entity_key,
-			l.unix_time AS unix_time,
-			%s
-		FROM %s AS l
-		LEFT JOIN %s AS r
-		ON l.entity_key = r.%s
-		WHERE l.unix_time >= $1 AND l.unix_time < $2;
-	`
-	featureNamesStr := buildFeatureNameStr(features)
-	for _, r := range revisionRanges {
-		_, tmpErr := db.ExecContext(ctx, fmt.Sprintf(joinQuery, entityDfWithFeatureName, featureNamesStr, featureNamesStr, entityDfName, r.DataTable, entity.Name), r.MinRevision, r.MaxRevision)
-		if tmpErr != nil {
-			return nil, tmpErr
-		}
-	}
-
-	// Step 2: get rows from entity_df_with_features table
-	resultQuery := fmt.Sprintf(`SELECT * FROM %s`, entityDfWithFeatureName)
-	rows, tmpErr := db.QueryxContext(ctx, resultQuery)
-	if tmpErr != nil {
-		return nil, tmpErr
-	}
-	defer rows.Close()
-
-	dataMap, err = getFeatureValueMapFromRows(rows, "unique_key")
-	return dataMap, err
-}
-
-func buildFeatureNameStr(features []*types.RichFeature) string {
-	featureNames := make([]string, 0, len(features))
-	for _, f := range features {
-		featureNames = append(featureNames, f.Name)
-	}
-	return strings.Join(featureNames, " ,")
-}