Logwatchchecks (and also other checks) that return quotes with values raise this Warning Message in zabbix-server and also in postgresql.log:

HINT: Use the escape string syntax for backslashes, e.g., E'
'.
WARNING: nonstandard use of
in a string literal
LINE 1: ....log,sshd
[]') or (h.host='vlxp01-dd' and i.key_='log[/var/...
^
HINT: Use the escape string syntax for backslashes, e.g., E'
'.
WARNING: nonstandard use of
in a string literal
LINE 1: ....log,sshd
[]') or (h.host='vlxp01-dd' and i.key_='log[/var/...
^
HINT: Use the escape string syntax for backslashes, e.g., E'
'.
WARNING: nonstandard use of
in a string literal
LINE 1: ....log,sshd
[]') or (h.host='vlxp01-dd' and i.key_='log[/var/...
^
HINT: Use the escape string syntax for backslashes, e.g., E'
'.
WARNING: nonstandard use of
in a string literal
LINE 1: ....log,sshd
[]') or (h.host='vlxp01-dd' and i.key_='log[/var/...
^
HINT: Use the escape string syntax for backslashes, e.g., E'
'.
WARNING: nonstandard use of
in a string literal
LINE 1: ....log,sshd
[]') or (h.host='vlxp01-dd' and i.key_='log[/var/...
^
HINT: Use the escape string syntax for backslashes, e.g., E'
'.

This concerns changes in postgresql 8.x that are discussed here:

• http://www.postgresql.org/docs/8.3/interactive/sql-syntax-lexical.html

It bulks the logfile a lot in both postgresql and zabbix-server, please fix.