7154aa16a6
Avoid accessing the leaf page's top parent tuple without a buffer lock held during the second phase of nbtree page deletion. The old approach was safe, though only because VACUUM never drops its buffer pin (and because only VACUUM itself can modify a half-dead page). Even still, it seems like a good idea to be strict here. Tighten things up by copying the top parent page's block number to a local variable before releasing the buffer lock on the leaf page -- not after. This is a follow-up to commit fa7ff642, which fixed a similar issue in the first phase of nbtree page deletion. Update some related comments in passing. Discussion: https://postgr.es/m/CAH2-WzkLgyN3zBvRZ1pkNJThC=xi_0gpWRUb_45eexLH1+k2_Q@mail.gmail.com
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/.