| 摘要 |
This disclosure provides systems and methods for updating database servers with schema changes to avoid concurrency anomalies. The system may receive a snapshot of a table to be updated with a new schema, wherein the snapshot is taken at a given time, and wherein the table includes a number of rows. The system may then read each row from the snapshot and read each row from the table to be updated at a second time. The system may then compare the rows read from the snapshot to the rows read from the table at the second time. Furthermore, the system may determine, based on the comparison, the rows from the snapshot that have not changed between the given time and the second time. The system may then write the rows that have not changed to the table to be updated.
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