python data_error ai_generated true

sqlalchemy.exc.StaleDataError: UPDATE statement on table 'users' expected to update 1 row(s); 0 were matched.

ID: python/sqlalchemy-stale-data-race

Also available as: JSON · Markdown · 中文
80%Fix Rate
82%Confidence
0Evidence
2024-05-20First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
1.4.x active — — —
2.0.x active — — —

Root Cause

Another transaction deleted or modified the row between the SELECT and UPDATE, causing the ORM's version check or rowcount to fail.

generic

中文

在 SELECT 和 UPDATE 之间，另一个事务删除或修改了该行，导致 ORM 的版本检查或行计数失败。

Workarounds

  1. 90% success 
    Implement optimistic locking with version_id_col: class User(Base): __mapper_args__ = {'version_id_col': version}
  2. 85% success 
    Catch StaleDataError and retry the whole transaction with fresh data: for attempt in range(3): try: update() break except StaleDataError: session.rollback()

Dead Ends

Common approaches that don't work:

  1. 70% fail

    Autoflush doesn't affect the underlying row version; the issue is concurrent modification, not flush timing.

  2. 60% fail

    Refresh may still see stale data if the other transaction hasn't committed yet; it doesn't solve the race condition.