3881561d77
Formerly, when updating an auto-updatable view, or a relation with rules, if the original query had any data-modifying CTEs, the rewriter would rewrite those CTEs multiple times as RewriteQuery() recursed into the product queries. In most cases that was harmless, because RewriteQuery() is mostly idempotent. However, if the CTE involved updating an always-generated column, it would trigger an error because any subsequent rewrite would appear to be attempting to assign a non-default value to the always-generated column. This could perhaps be fixed by attempting to make RewriteQuery() fully idempotent, but that looks quite tricky to achieve, and would probably be quite fragile, given that more generated-column-type features might be added in the future. Instead, fix by arranging for RewriteQuery() to rewrite each CTE exactly once (by tracking the number of CTEs already rewritten as it recurses). This has the advantage of being simpler and more efficient, but it does make RewriteQuery() dependent on the order in which rewriteRuleAction() joins the CTE lists from the original query and the rule action, so care must be taken if that is ever changed. Reported-by: Bernice Southey <bernice.southey@gmail.com> Author: Bernice Southey <bernice.southey@gmail.com> Author: Dean Rasheed <dean.a.rasheed@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Kirill Reshke <reshkekirill@gmail.com> Discussion: https://postgr.es/m/CAEDh4nyD6MSH9bROhsOsuTqGAv_QceU_GDvN9WcHLtZTCYM1kA@mail.gmail.com Backpatch-through: 14
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.