Jonathan Clarke wrote:
Hi,
I've set up an ldap backend, with a pcache overlay to cache binds for PAM.
The config is below, for info.
My question concerns the pcachePersist parameter. From the man page:
pcachePersist { TRUE | FALSE }
Specify whether the cached queries should be saved across restarts of
the caching proxy, to provide hot startup of the cache. Only non-expired
queries are reloaded. The default is FALSE.
As I understand this, given pcachePersist FALSE (or not specified),
cached queries should no longer be in the cache after restarting slapd. Am
I right?
However, once a bind is successfully cached, I take the proxied server
offline and I can restart slapd many times, however my bind is still served
from cache.
Is this a bug in the docs, a bug in the implementation or just me not
getting something?
The proxycache writes all cached data into the cache DB. As such, cached
results are always present after a restart; this has always been the case.
That can be considered a bug, because it did not save any information about
the queries to which each cached entry belonged. So on a restart, the cache DB
contains stuff but the overlay doesn't know about it.
With pcachePersist set TRUE, the query info is also stored in the DB, and
re-loaded on restart. Thus the overlay will know the complete contents of the
cache DB.
Thanks,
Jonathan
PS: the simplified config:
8--
databaseldap
suffix dc=proxy
rootdn cn=manager,dc=proxy
uri ldap://my.other.ldap.server/
timeout 5
overlay pcache
pcache hdb 1 1 2 60
pcacheAttrset 0 *
# cache binds for 900 seconds = 15 minutes
pcacheTemplate (uid=) 0 900
pcacheBind (uid=) 0 900 sub dc=proxy
pcachePersist FALSE
pcacheOffline FALSE
directory /var/cache/ldap
cachesize 1
index objectClass,sAMAccountName,pcacheQueryideq
8--
--
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/
