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If a query against an inheritance tree runs concurrently with an ALTER TABLE that's disinheriting one of the tree members, it's possible to get a "could not find inherited attribute" error because after obtaining lock on the removed member, make_inh_translation_list sees that its columns have attinhcount=0 and decides they aren't the columns it's looking for. An ideal fix, perhaps, would avoid including such a just-removed member table in the query at all; but there seems no way to accomplish that without adding expensive catalog rechecks or creating a likelihood of deadlocks. Instead, let's just drop the check on attinhcount. In this way, a query that's included a just-disinherited child will still succeed, which is not a completely unreasonable behavior. This problem has existed for a long time, so back-patch to all supported branches. Also add an isolation test verifying related behaviors. Patch by me; the new isolation test is based on Kyotaro Horiguchi's work. Discussion: https://postgr.es/m/20170626.174612.23936762.horiguchi.kyotaro@lab.ntt.co.jp
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. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.