Vacuum/corruption

Hi folks,

Looking for suggestions..

Have a table with 5 cols. about 1 gig, on a dual
PII 450, 512 megs of ram, running redhat. How long
should a vacuum take ?

Also , could droping an index while data is being inserted
corrupt a table ? I thinking there is data corruption because
i get the following error in 2 situations
   1: while trying to do a select into
   2: while trying to recreate the index.

getranked=> create index click_timestamp_idx on clicks (timestamp);
pqReadData() -- backend closed the channel unexpectedly.
        This probably means the backend terminated abnormally
        before or while processing the request.
We have lost the connection to the backend, so further processing is
impossible.  Terminating.

also got this error in the log..

StartTransactionCommand
ProcessUtility
/usr/bin/postmaster: reaping dead processes...
/usr/bin/postmaster: CleanupProc: pid 31209 exited with status 139
/usr/bin/postmaster: CleanupProc: sending SIGUSR1 to process 31208
/usr/bin/postmaster: CleanupProc: sending SIGUSR1 to process 31204
/usr/bin/postmaster: CleanupProc: sending SIGUSR1 to process 31203
/usr/bin/postmaster: CleanupProc: sending SIGUSR1 to process 31201
NOTICE:  Message from PostgreSQL backend:
        The Postmaster has informed me that some other backend died
abnormally and possibly corrupted shared memory.
        I have rolled back the current transaction and am going to terminate
your database system connection and exit.
        Please reconnect to the database system and repeat your query.
/usr/bin/postmaster: CleanupProc: reinitializing shared memory and
semaphores
shmem_exit(0) [#0]
NOTICE:  Message from PostgreSQL backend:
        The Postmaster has informed me that some other backend died
abnormally and possibly corrupted shared memory.
        I have rolled back the current transaction and am going to terminate
your database system connection and exit.
        Please reconnect to the database system and repeat your query.
/usr/bin/postmaster: CleanupProc: pid 31208 exited with status 0
NOTICE:  Message from PostgreSQL backend:
        The Postmaster has informed me that some other backend died
abnormally and possibly corrupted shared memory.
        I have rolled back the current transaction and am going to terminate
your database system connection and exit.
        Please reconnect to the database system and repeat your query.
/usr/bin/postmaster: CleanupProc: pid 31201 exited with status 0
/usr/bin/postmaster: reaping dead processes...
NOTICE:  Message from PostgreSQL backend:
        The Postmaster has informed me that some other backend died
abnormally and possibly corrupted shared memory.
        I have rolled back the current transaction and am going to terminate
your database system connection and exit.
        Please reconnect to the database system and repeat your query.
/usr/bin/postmaster: reaping dead processes...
/usr/bin/postmaster: CleanupProc: pid 31203 exited with status 0
/usr/bin/postmaster: reaping dead processes...
/usr/bin/postmaster: CleanupProc: pid 31204 exited with status 0

======================================================
Jeff MacDonald
    jeff@pgsql.com    irc: bignose on EFnet
======================================================