"Ben-Nes Michael" <miki@canaan.co.il> writes:
> VACUUM ANALYZE;
> pqReadData() -- backend closed the channel unexpectedly.
Can't help you with so little information. What Postgres version?
What platform? What shows up in the postmaster's stderr log?
(If you aren't keeping one, now's a good time to start.) Is there
a core file produced by the failed backend, and if so what do you
get from a debugger stack trace?
regards, tom lane