How to repair Pg 9.1?

Recently I started a hard query (ALTER TABLE) and then Postgresql was
killed by OOM killer.

Since that clients lose their connection and Postgresql says in log:

2012-04-15 16:46:02 MSK LOG: server process (PID 825) was terminated by signal 11: Segmentation fault
2012-04-15 16:46:02 MSK LOG: terminating any other active server processes
2012-04-15 16:46:02 MSK WARNING: terminating connection because of crash of another server process
2012-04-15 16:46:02 MSK DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2012-04-15 16:46:02 MSK HINT: In a moment you should be able to reconnect to the database and repeat your command.
2012-04-15 16:46:02 MSK WARNING: terminating connection because of crash of another server process
2012-04-15 16:46:02 MSK DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2012-04-15 16:46:02 MSK HINT: In a moment you should be able to reconnect to the database and repeat your command.
2012-04-15 16:46:02 MSK WARNING: terminating connection because of crash of another server process
2012-04-15 16:46:02 MSK DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2012-04-15 16:46:02 MSK HINT: In a moment you should be able to reconnect to the database and repeat your command.
2012-04-15 16:46:02 MSK LOG: all server processes terminated; reinitializing
2012-04-15 16:46:02 MSK LOG: database system was interrupted; last known up at 2012-04-15 16:45:17 MSK
2012-04-15 16:46:02 MSK LOG: database system was not properly shut down; automatic recovery in progress
2012-04-15 16:46:02 MSK LOG: consistent recovery state reached at 58/21C44D18
2012-04-15 16:46:02 MSK LOG: redo starts at 58/21C44D18
2012-04-15 16:46:02 MSK LOG: record with zero length at 58/21CA7E20
2012-04-15 16:46:02 MSK LOG: redo done at 58/21CA7DE0
2012-04-15 16:46:02 MSK LOG: last completed transaction was at log time 2012-04-15 16:46:02.620188+04
2012-04-15 16:46:02 MSK LOG: autovacuum launcher started
2012-04-15 16:46:02 MSK LOG: database system is ready to accept connections

What can I do in the situation?

Postgresql 9.1/Debian wheezy
--

. ''`. Dmitry E. Oboukhov
: :’ : email: unera(at)debian(dot)org jabber://UNera(at)uvw(dot)ru
`. `~’ GPGKey: 1024D / F8E26537 2006-11-21
`- 1B23 D4F8 8EC0 D902 0555 E438 AB8C 00CF F8E2 6537