c6ade7a8cd
On standby ginRedoDeletePage() can work concurrently with read-only queries. Those queries can traverse posting tree in two ways. 1) Using rightlinks by ginStepRight(), which locks the next page before unlocking its left sibling. 2) Using downlinks by ginFindLeafPage(), which locks at most one page at time. Original lock order was: page, parent, left sibling. That lock order can deadlock with ginStepRight(). In order to prevent deadlock this commit changes lock order to: left sibling, page, parent. Note, that position of parent in locking order seems insignificant, because we only lock one page at time while traversing downlinks. Reported-by: Chen Huajun Diagnosed-by: Chen Huajun, Peter Geoghegan, Andrey Borodin Discussion: https://postgr.es/m/31a702a.14dd.166c1366ac1.Coremail.chjischj%40163.com Author: Alexander Korotkov Backpatch-through: 9.4
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/.