

Prefetch User Database
======================


Prefetch userdb can be used to combine passdb and userdb lookups into a single lookup. It's usually used with >>SQL<<, >>LDAP<< and >>checkpassword<< passdbs. 
Prefetch basically works by requiring that the passdb returns the userdb information in >>extra fields<< with 'userdb_' prefixes. For example if a userdb typically returns 'uid', 'gid' and 'home' fields, the passdb would have to return 'userdb_uid', 'userdb_gid' and 'userdb_home' fields. 
If you're using >>deliver<<, you still need a valid userdb which can be used to locate the users. You can do this by adding a normal SQL/LDAP userdb after the userdb prefetch. See below for examples. 
LDAP's 'auth_bind_userdn=yes' setting is incompatible with prefetch, because no passdb lookup is done then. If you want zero LDAP lookups, you might want to user >>static userdb<< instead of prefetch. 


SQL example
===========


'dovecot.conf': 
---%<-------------------------------------------------------------------------
passdb sql {
  args = /etc/dovecot-sql.conf
}
userdb prefetch {
}
# The userdb below is used only by deliver.
userdb sql {
  args = /etc/dovecot-sql.conf
}
---%<-------------------------------------------------------------------------

'dovecot-sql.conf': 
---%<-------------------------------------------------------------------------
# NOTE: '\' line splitting is used only for readability, currently Dovecot doesn't support it
password_query = SELECT password, \
  home AS userdb_home, uid AS userdb_uid, gid AS userdb_gid \
  FROM users \
  WHERE userid = '%u'

# For deliver:
user_query = SELECT home, uid, gid FROM users WHERE userid = '%u'
---%<-------------------------------------------------------------------------



LDAP example
============


'dovecot.conf': 
---%<-------------------------------------------------------------------------
passdb ldap {
  args = /etc/dovecot-ldap.conf
}
userdb prefetch {
}
# The userdb below is used only by deliver.
userdb ldap {
  args = /etc/dovecot-ldap.conf
}
---%<-------------------------------------------------------------------------

'dovecot-ldap.conf': 
---%<-------------------------------------------------------------------------
# NOTE: '\' line splitting is used only for readability, currently Dovecot doesn't support it
pass_attrs = uid=user,userPassword=password, \
  homeDirectory=userdb_home,uidNumber=userdb_uid,gidNumber=userdb_gid

# For deliver:
user_attrs = homeDirectory=home,uidNumber=uid,gidNumber=gid
---%<-------------------------------------------------------------------------

(This file was created from the wiki on 2007-12-11 04:42)
