Cleanup snapshot flow, fixing two issues (#1146)

1. identifier quoting wasn't using QuoteIdentifier
2. mapping.Exclude wasn't being used to actually remove excluded columns

flow/workflows/snapshot_flow.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"log/slog"
 	"regexp"
+	"slices"
 	"strings"
 	"time"
 
@@ -13,6 +14,7 @@ import (
 	"go.temporal.io/sdk/workflow"
 
 	"github.com/PeerDB-io/peer-flow/concurrency"
+	connpostgres "github.com/PeerDB-io/peer-flow/connectors/postgres"
 	"github.com/PeerDB-io/peer-flow/connectors/utils"
 	"github.com/PeerDB-io/peer-flow/generated/protos"
 	"github.com/PeerDB-io/peer-flow/shared"
@@ -141,11 +143,13 @@ func (s *SnapshotFlowExecution) cloneTable(
 	if len(mapping.Exclude) != 0 {
 		for _, v := range s.tableNameSchemaMapping {
 			if v.TableIdentifier == srcName {
-				colNames := utils.TableSchemaColumnNames(v)
-				for i, colName := range colNames {
-					colNames[i] = fmt.Sprintf(`"%s"`, colName)
+				quotedColumns := make([]string, 0, len(v.ColumnNames))
+				for _, colName := range v.ColumnNames {
+					if !slices.Contains(mapping.Exclude, colName) {
+						quotedColumns = append(quotedColumns, connpostgres.QuoteIdentifier(colName))
+					}
 				}
-				from = strings.Join(colNames, ",")
+				from = strings.Join(quotedColumns, ",")
 				break
 			}
 		}
@@ -254,20 +258,15 @@ func SnapshotFlowWorkflow(ctx workflow.Context, config *protos.FlowConnectionCon
 		logger: logger,
 	}
 
-	numTablesInParallel := int(config.SnapshotNumTablesInParallel)
-	if numTablesInParallel <= 0 {
-		numTablesInParallel = 1
-	}
-
-	replCtx := ctx
+	numTablesInParallel := int(max(config.SnapshotNumTablesInParallel, 1))
 
 	if !config.DoInitialSnapshot {
-		_, err := se.setupReplication(replCtx)
+		_, err := se.setupReplication(ctx)
 		if err != nil {
 			return fmt.Errorf("failed to setup replication: %w", err)
 		}
 
-		if err := se.closeSlotKeepAlive(replCtx); err != nil {
+		if err := se.closeSlotKeepAlive(ctx); err != nil {
 			return fmt.Errorf("failed to close slot keep alive: %w", err)
 		}