diff options
Diffstat (limited to 'internal/database/database.go')
| -rw-r--r-- | internal/database/database.go | 38 |
1 files changed, 19 insertions, 19 deletions
diff --git a/internal/database/database.go b/internal/database/database.go index 3e009e1c..2bd6b8cc 100644 --- a/internal/database/database.go +++ b/internal/database/database.go @@ -116,16 +116,26 @@ func (db *DB) RunQuery(ctx context.Context, query string, f func(*sql.Rows) erro return rows.Err() } -// Transact executes the given function in the context of a SQL transaction, -// rolling back the transaction if the function panics or returns an error. It -// uses the default transaction options. +// Transact executes the given function in the context of a SQL transaction at +// the given isolation level, rolling back the transaction if the function +// panics or returns an error. // // The given function is called with a DB that is associated with a transaction. // The DB should be used only inside the function; if it is used to access the // database after the function returns, the calls will return errors. -func (db *DB) Transact(ctx context.Context, txFunc func(*DB) error) (err error) { - defer derrors.Wrap(&err, "Transact") - return db.transact(ctx, nil, txFunc) +// +// If the isolation level requires it, Transact will retry the transaction upon +// serialization failure, so txFunc may be called more than once. + +func (db *DB) Transact(ctx context.Context, iso sql.IsolationLevel, txFunc func(*DB) error) (err error) { + defer derrors.Wrap(&err, "Transact(%s)", iso) + // For the levels which require retry, see + // https://www.postgresql.org/docs/11/transaction-iso.html. + opts := &sql.TxOptions{Isolation: iso} + if iso == sql.LevelRepeatableRead || iso == sql.LevelSerializable { + return db.transactWithRetry(ctx, opts, txFunc) + } + return db.transact(ctx, opts, txFunc) } // serializationFailureCode is the Postgres error code returned when a serializable @@ -133,23 +143,13 @@ func (db *DB) Transact(ctx context.Context, txFunc func(*DB) error) (err error) // See https://www.postgresql.org/docs/current/errcodes-appendix.html. const serializationFailureCode = "40001" -// TransactSerializable executes the given function in the context of a SQL transaction, -// rolling back the transaction if the function panics or returns an error. It uses -// the given context and the Serializable transaction isolation level. -// -// The given function is called with a DB that is associated with a transaction. -// The DB should be used only inside the function; if it is used to access the -// database after the function returns, the calls will return errors. -// -// TransactSerializable will retry the transaction upon serialization failure, so txFunc -// may be called more than once. -func (db *DB) TransactSerializable(ctx context.Context, txFunc func(*DB) error) (err error) { - defer derrors.Wrap(&err, "TransactSerializable") +func (db *DB) transactWithRetry(ctx context.Context, opts *sql.TxOptions, txFunc func(*DB) error) (err error) { + defer derrors.Wrap(&err, "transactWithRetry(%v)", opts) // Retry on serialization failure, up to some max. // See https://www.postgresql.org/docs/11/transaction-iso.html. const maxRetries = 30 for i := 0; i <= maxRetries; i++ { - err = db.transact(ctx, &sql.TxOptions{Isolation: sql.LevelSerializable}, txFunc) + err = db.transact(ctx, opts, txFunc) var perr *pq.Error if errors.As(err, &perr) && perr.Code == serializationFailureCode { db.mu.Lock() |