Revert "retry on serialization errors"

storage/sql/sql.go

@@ -2,15 +2,14 @@
 package sql
 
 import (
-	"context"
 	"database/sql"
 	"regexp"
 	"time"
 
-	"github.com/lib/pq"
 	"github.com/sirupsen/logrus"
 
 	// import third party drivers
+	_ "github.com/lib/pq"
 	_ "github.com/mattn/go-sqlite3"
 )
 
@@ -40,66 +39,31 @@ func matchLiteral(s string) *regexp.Regexp {
 	return regexp.MustCompile(`\b` + regexp.QuoteMeta(s) + `\b`)
 }
 
-// Detect a serialization failure, which should trigger retrying the
-// transaction according to PostgreSQL docs:
-//
-// https://www.postgresql.org/docs/current/transaction-iso.html#XACT-SERIALIZABLE
-//
-// "applications using this level must be prepared to retry transactions due to
-// serialization failures"
-func isRetryableSerializationFailure(err error) bool {
-	if pqErr, ok := err.(*pq.Error); ok {
-		return pqErr.Code.Name() == "serialization_failure"
-	}
-
-	return false
-}
-
 var (
 	// The "github.com/lib/pq" driver is the default flavor. All others are
 	// translations of this.
 	flavorPostgres = flavor{
-		// The default behavior for Postgres transactions is consistent reads, not
-		// consistent writes. For each transaction opened, ensure it has the
-		// correct isolation level.
+		// The default behavior for Postgres transactions is consistent reads, not consistent writes.
+		// For each transaction opened, ensure it has the correct isolation level.
 		//
 		// See: https://www.postgresql.org/docs/9.3/static/sql-set-transaction.html
 		//
-		// Be careful not to wrap sql errors in the callback 'fn', otherwise
-		// serialization failures will not be detected and retried.
+		// NOTE(ericchiang): For some reason using `SET SESSION CHARACTERISTICS AS TRANSACTION` at a
+		// session level didn't work for some edge cases. Might be something worth exploring.
 		executeTx: func(db *sql.DB, fn func(sqlTx *sql.Tx) error) error {
-			ctx, cancel := context.WithCancel(context.TODO())
-			defer cancel()
-
-			opts := &sql.TxOptions{
-				Isolation: sql.LevelSerializable,
+			tx, err := db.Begin()
+			if err != nil {
+				return err
 			}
+			defer tx.Rollback()
 
-			for {
-				tx, err := db.BeginTx(ctx, opts)
-				if err != nil {
-					return err
-				}
-
-				if err := fn(tx); err != nil {
-					if isRetryableSerializationFailure(err) {
-						continue
-					}
-
-					return err
-				}
-
-				err = tx.Commit()
-				if err != nil {
-					if isRetryableSerializationFailure(err) {
-						continue
-					}
-
-					return err
-				}
-
-				return nil
+			if _, err := tx.Exec(`SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;`); err != nil {
+				return err
 			}
+			if err := fn(tx); err != nil {
+				return err
+			}
+			return tx.Commit()
 		},
 
 		supportsTimezones: true,