mirror of
https://github.com/postgres/postgres.git
synced 2025-05-28 05:21:27 +03:00
f4d4bc827f
address of afterTriggers->query_stack[afterTriggers->query_depth] and hung onto it through all its firings of triggers. However, if a trigger causes sufficiently many nested query executions, query_stack will get repalloc'd bigger, leaving AfterTriggerEndQuery --- and hence afterTriggerInvokeEvents --- using a stale pointer. So far as I can find, the only consequence of this error is to stomp on a couple of words of already-freed memory; which would lead to a failure only if that chunk had already gotten re-allocated for something else. So it's hard to exhibit a simple failure case, but this is surely a bug. I noticed this while working on my recent patch to reduce pending-trigger space usage. The present patch is mighty ugly, because it requires making afterTriggerInvokeEvents know about all the possible event lists it might get called on. Fortunately, this is only needed in back branches because CVS HEAD avoids the problem in a different way: afterTriggerInvokeEvents only touches the passed AfterTriggerEventList pointer once at startup. Back branches are stable enough that wiring in knowledge of all possible call usages doesn't seem like a killer problem. Back-patch to 8.0. 7.4's trigger code is completely different and doesn't seem to have the problem (it doesn't even use repalloc).
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 including some of the more common listed below: C++ - http://thaiopensource.org/development/libpqxx/ JDBC - http://jdbc.postgresql.org ODBC - http://odbc.postgresql.org Perl - http://search.cpan.org/~dbdpg/ PHP - http://www.php.net Python - http://www.initd.org/ Ruby - http://ruby.scripting.ca/postgres/ Other language binding are available from a variety of contributing parties. PostgreSQL also has a great number of procedural languages available, a short but not complete list is below: PL/pgSQL - included in PostgreSQL source distribution PL/Perl - included in PostgreSQL source distribution PL/PHP - http://projects.commandprompt.com/projects/public/plphp PL/Python - included in PostgreSQL source distribution PL/Java - http://gborg.postgresql.org/project/pljava/projdisplay.php PL/Tcl - included in PostgreSQL source distribution 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/.