ea8e1bbc53
Previously, although the initial state of a proclist_node is expected to be next == prev == 0, proclist_delete_offset would reset nodes to next == prev == INVALID_PGPROCNO when removing them from a list. This is the same state that a node in a singleton list has, so that it's impossible to distinguish not-in-a-list from in-a-list. Change proclist_delete_offset to reset removed nodes to next == prev == 0, making it possible to distinguish those cases, and then add Asserts to the list add and delete functions that the supplied node isn't or is in a list at entry. Also tighten assertions about the node being in the particular list (not some other one) where it is possible to check that in O(1) time. In ConditionVariablePrepareToSleep, since we don't expect the process's cvWaitLink to already be in a list, remove the more-or-less-useless proclist_contains check; we'd rather have proclist_push_tail's new assertion fire if that happens. Improve various comments related to proclists, too. Patch by me, reviewed by Thomas Munro. This isn't back-patchable, since there could theoretically be inlined copies of proclist_delete_offset in third-party modules. But it's only improving debuggability anyway. Discussion: https://postgr.es/m/CAEepm=0NWKehYw7NDoUSf8juuKOPRnCyY3vuaSvhrEWsOTAa3w@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/.