"bh yuan" <bhyuan@xxxxxxxxx> writes: > I use Postgresql 7.4.19 wiht 8G memory on Redhat5 x86_64. > And I modify the postgresql.conf file, > when I set > shared_buffers = 786432 # min 16, at least 7.4 does not support more than 2Gb (or maybe 4Gb, I forget) of shared memory. Furthermore, it so little imagines that you might want that much that it doesn't even guard itself against overflow. This is not really a problem because its buffer management algorithms are not good enough to support more than a few tens of thousands of shared buffers anyway. In short: don't do that. Modern versions of PG (say, 8.1 or later) are somewhat competent with large amounts of shared buffers. Why are you even trying such an obsolete version of PG on RHEL5? What Red Hat ships in RHEL5 is 8.1, and even that is pretty old in the view of most people on this list. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org/