## E.169. Release 8.2.21

### Release Date

2011-04-18

This release contains a variety of fixes from 8.2.20. For information about new features in the 8.2 major release, see Section E.190, “Release 8.2”.

### E.169.1. Migration to Version 8.2.21

A dump/restore is not required for those running 8.2.X. However, if you are upgrading from a version earlier than 8.2.14, see Section E.176, “Release 8.2.14”.

### E.169.2. Changes

- Avoid potential deadlock during catalog cache initialization (Nikhil Sontakke)

  In some cases the cache loading code would acquire share lock on a system index before locking the index's catalog. This could deadlock against processes trying to acquire exclusive locks in the other, more standard order.

- Fix dangling-pointer problem in `BEFORE ROW UPDATE` trigger handling when there was a concurrent update to the target tuple (Tom Lane)

  This bug has been observed to result in intermittent “cannot extract system attribute from virtual tuple” failures while trying to do `UPDATE RETURNING ctid`. There is a very small probability of more serious errors, such as generating incorrect index entries for the updated tuple.

- Disallow `DROP TABLE` when there are pending deferred trigger events for the table (Tom Lane)

  Formerly the `DROP` would go through, leading to “could not open relation with OID nnn” errors when the triggers were eventually fired.

- Fix PL/Python memory leak involving array slices (Daniel Popowich)

- Fix pg_restore to cope with long lines (over 1KB) in TOC files (Tom Lane)

- Put in more safeguards against crashing due to division-by-zero with overly enthusiastic compiler optimization (Aurelien Jarno)

- Support use of dlopen() in FreeBSD and OpenBSD on MIPS (Tom Lane)

  There was a hard-wired assumption that this system function was not available on MIPS hardware on these systems. Use a compile-time test instead, since more recent versions have it.

- Fix compilation failures on HP-UX (Heikki Linnakangas)

- Fix path separator used by pg_regress on Cygwin (Andrew Dunstan)

- Update time zone data files to tzdata release 2011f for DST law changes in Chile, Cuba, Falkland Islands, Morocco, Samoa, and Turkey; also historical corrections for South Australia, Alaska, and Hawaii.