This page in other versions: 8.4 / 9.0 / 9.1 / 9.2 / 9.3  |  Development versions: devel / 9.4  |  Unsupported versions: 7.1 / 7.2 / 7.3 / 7.4 / 8.0 / 8.1 / 8.2 / 8.3

17.4. Visibility of Data Changes

PostgreSQL data changes visibility rule: during a query execution, data changes made by the query itself (via SQL-function, SPI-function, triggers) are invisible to the query scan. For example, in query

   INSERT INTO a SELECT * FROM a

tuples inserted are invisible for SELECT's scan. In effect, this duplicates the database table within itself (subject to unique index rules, of course) without recursing.

Changes made by query Q are visible to queries that are started after query Q, no matter whether they are started inside Q (during the execution of Q) or after Q is done.

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group