A request for serializable transaction isolation actually provided snapshot isolation.
#Postgresql serial full
The SQL standard provides a specific SQLSTATE for errors generated when a transaction rolls back for this reason, so that transactions can be retried automatically.īefore version 9.1, PostgreSQL did not support a full serializable isolation level. Where conflicts with other transactions would result in an inconsistent state within the database or an inconsistent view of the data, a serializable transaction will block or roll back to prevent the anomaly. Serializable transaction isolation is attractive for shops with active development by many programmers against a complex schema because it guarantees data integrity with very little staff time - if a transaction can be shown to always do the right thing when it is run alone (before or after any other transaction), it will always do the right thing in any mix of concurrent serializable transactions.
Serializable and Snapshot Transaction Isolation Levels Another description of SSI and how PostgreSQL's implementation differs from previous work is available in our paper Serializable Snapshot Isolation in PostgreSQL from VLDB 2012. For information oriented toward application programmers and database administrators, see the SSI Wiki page. This document is oriented toward the techniques used to implement the feature in PostgreSQL. With true serializable transactions, if you can show that your transaction will do the right thing if there are no concurrent transactions, it will do the right thing in any mix of serializable transactions or be rolled back with a serialization failure.
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