23c58c38e6
First, when following a right-link, we incorrectly marked the current page as the parent of the right sibling. In reality, the parent of the right page is the same as the parent of the current page (or some page to the right of it, gistFindCorrectParent() will sort that out). Secondly, when we follow a right-link, we must prepend, not append, the right page to our list of pages to visit. That's because we assume that once we hit a leaf page in the list, all the rest are leaf pages too, and give up. To hit these bugs, you need concurrent actions and several unlucky accidents. Another backend must split the root page, while you're in process of splitting a lower-level page. Furthermore, while you scan the internal nodes to re-find the parent, another backend needs to again split some more internal pages. Even then, the bugs don't necessarily manifest as user-visible errors or index corruption. While we're at it, make the error reporting a bit better if gistFindPath() fails to re-find the parent. It used to be an assertion, but an elog() seems more appropriate. Backpatch to all supported branches.
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: http://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. Changes between all PostgreSQL releases are recorded in the file HISTORY. 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 http://www.postgresql.org/download/. For more information look at our web site located at http://www.postgresql.org/.