proxymap uses 99% CPU

Hi

I use postfix 2.2.2 on SuSE Linux 9.2. It serves ~80 users and works
pretty fine. But 5-10 times a day, it starts a proxymap which then does
not terminate and uses 99% CPU. In /var/log/messages, I see this after
proxymap starts:

May 11 04:22:14 4s-box postfix/master[26558]: warning: process
/usr/lib/postfix/proxymap pid 30457 killed by signal 11
May 11 06:00:28 4s-box postfix/smtpd[31409]: warning: timeout on
private/proxymap socket while reading input attribute name
May 11 06:00:28 4s-box postfix/smtpd[31409]: warning:
dict_proxy_lookup: service private/proxymap socket: Connection timed
out
May 11 06:33:22 4s-box postfix/master[26558]: warning: process
/usr/lib/postfix/proxymap pid 30962 killed by signal 15
May 11 06:37:55 4s-box postfix/smtpd[31656]: warning: premature
end-of-input on private/proxymap socket while reading input attribute
name
May 11 06:37:55 4s-box postfix/smtpd[31656]: warning:
dict_proxy_lookup: service private/proxymap socket: Success

What ca I do to stop this? See below for main.cf
Many thanks for any suggestions.

Benjamin

main.cf:
queue_directory = /var/spool/postfix
daemon_directory = /usr/lib/postfix
mail_owner = postfix
unknown_local_recipient_reject_code = 550
debug_peer_level = 255
debugger_command =
PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin
xxgdb $daemon_directory/$process_name $process_id & sleep 5
sendmail_path = /usr/sbin/sendmail
newaliases_path = /usr/bin/newaliases
mailq_path = /usr/bin/mailq
setgid_group = maildrop
html_directory = /usr/share/doc/packages/postfix/html
manpage_directory = /usr/share/man
sample_directory = /usr/share/doc/packages/postfix/samples
readme_directory = /usr/share/doc/packages/postfix/README_FILES
mynetworks = x.x.x.x,y.y.y.y,z.z.z.z

biff = no
mail_spool_directory = /var/mail


canonical_maps = hash:/etc/postfix/canonical
virtual_maps = hash:/etc/postfix/virtual
relocated_maps = hash:/etc/postfix/relocated
transport_maps = hash:/etc/postfix/transport
sender_canonical_maps = hash:/etc/postfix/sender_canonical


masquerade_exceptions = root
masquerade_classes = envelope_sender, header_sender, header_recipient
myhostname = 4s-box.4s-hosting.ch
myorigin = $mydomain
program_directory = /usr/lib/postfix
inet_interfaces = all
masquerade_domains =
mydestination = $myhostname, localhost.$mydomain, $mydomain,
mail.$mydomain
defer_transports =
disable_dns_lookups = no
relayhost =
mailbox_command = /usr/bin/procmail
mailbox_transport =
strict_rfc821_envelopes = no


smtpd_helo_required = yes
smtpd_delay_reject = yes
smtpd_helo_restrictions =
permit_mynetworks,
reject_invalid_hostname,
reject_non_fqdn_hostname


smtpd_client_restrictions =
permit_sasl_authenticated,
permit_mynetworks,
reject_unknown_client


smtpd_sender_restrictions =
reject_unknown_sender_domain


smtpd_recipient_restrictions =
permit_mynetworks,
check_client_access hash:/etc/postfix/client_access,
reject_unauth_destination


smtp_sasl_auth_enable = no
smtpd_use_tls = no
smtp_use_tls = no
alias_maps = hash:/etc/aliases
virtual_alias_domains = hash:/etc/postfix/maildomains

smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
broken_sasl_auth_clients = yes