compareTables test: drop loop by not using prepared statements for qu…

…ery (#1056)

https://pkg.go.dev/github.com/jackc/pgx/v5#QueryExecMode

flow/e2e/postgres/qrep_flow_pg_test.go

@@ -13,6 +13,7 @@ import (
 	"github.com/PeerDB-io/peer-flow/e2eshared"
 	"github.com/PeerDB-io/peer-flow/generated/protos"
 	"github.com/PeerDB-io/peer-flow/shared"
+	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgtype"
 	"github.com/jackc/pgx/v5/pgxpool"
 	"github.com/joho/godotenv"
@@ -82,28 +83,11 @@ func (s PeerFlowE2ETestSuitePG) setupSourceTable(tableName string, rowCount int)
 
 func (s PeerFlowE2ETestSuitePG) comparePGTables(srcSchemaQualified, dstSchemaQualified, selector string) error {
 	// Execute the two EXCEPT queries
-	for {
-		err := s.compareQuery(srcSchemaQualified, dstSchemaQualified, selector)
-		// while testing, the prepared plan might break due to schema changes
-		// solution is to retry, prepared statement should be evicted upon the first error
-		if err != nil && !strings.Contains(err.Error(), "cached plan must not change result type") {
-			return err
-		}
-		if err == nil {
-			break
-		}
+	if err := s.compareQuery(srcSchemaQualified, dstSchemaQualified, selector); err != nil {
+		return err
 	}
-
-	for {
-		err := s.compareQuery(dstSchemaQualified, srcSchemaQualified, selector)
-		// while testing, the prepared plan might break due to schema changes
-		// solution is to retry, prepared statement should be evicted upon the first error
-		if err != nil && !strings.Contains(err.Error(), "cached plan must not change result type") {
-			return err
-		}
-		if err == nil {
-			break
-		}
+	if err := s.compareQuery(dstSchemaQualified, srcSchemaQualified, selector); err != nil {
+		return err
 	}
 
 	// If no error is returned, then the contents of the two tables are the same
@@ -131,7 +115,7 @@ func (s PeerFlowE2ETestSuitePG) checkEnums(srcSchemaQualified, dstSchemaQualifie
 func (s PeerFlowE2ETestSuitePG) compareQuery(srcSchemaQualified, dstSchemaQualified, selector string) error {
 	query := fmt.Sprintf("SELECT %s FROM %s EXCEPT SELECT %s FROM %s", selector, srcSchemaQualified,
 		selector, dstSchemaQualified)
-	rows, err := s.pool.Query(context.Background(), query)
+	rows, err := s.pool.Query(context.Background(), query, pgx.QueryExecModeExec)
 	if err != nil {
 		return err
 	}