Re: (ITS#6310) Slapd with pcache crashes under load

[karavelov@spnet.net]

masarati@aero.polimi.it wrote:
> No.  Some overlay along the lines apparently mucks with e_private in the
> entry that back-ldap is sending.  It's probably slapo-pcache.  I need to
> debug this.  You say it happens seldom.  Can you recognize anything
> special in the operation that triggers the assertion failure?  I mean:
> either in terms of special data, or in terms of special state of the
> cache?  This could help narrow down some means to reproduce the issue.
>
> Thanks, p.
>
>
>   
What is interesting is that most of the logs are something like this one:

conn=6891 op=1 SRCH attr=spamassassin
query template of incoming query = (&(objectClass=)(cn=))
Entering QC, querystr = (&(objectClass=mailUser)(cn=nobody))
Lock QC index = 0x7e0a7b8
QUERY ANSWERABLE (answered 3267 times)
conn=6891 op=1 SEARCH RESULT tag=101 err=0 nentries=0 text=
conn=6891 fd=32 closed (connection lost)
query template of incoming query = (&(objectClass=)(uid=))
QUERY NOT ANSWERABLE
QUERY NOT CACHEABLE
query template of incoming query = (&(objectClass=)(uid=))
QUERY NOT ANSWERABLE
QUERY NOT CACHEABLE
query template of incoming query = (&(objectClass=)(uid=))
QUERY NOT ANSWERABLE
QUERY NOT CACHEABLE
query template of incoming query = (&(objectClass=)(uid=))
QUERY NOT ANSWERABLE
QUERY NOT CACHEABLE
query template of incoming query = (&(objectClass=)(uid=))
QUERY NOT ANSWERABLE
QUERY NOT CACHEABLE
conn=3573 op=812 SRCH base="dc=ciela.net,dc=hosting,dc=spnet,dc=net" 
scope=1 deref=0 filter="(&(objectClass=mailUser)(uid=diana))"
conn=3573 op=812 SRCH attr=uid userPassword mailMessageStore uidNumber 
gidNumber
query template of incoming query = (&(objectClass=)(uid=))
Entering QC, querystr = (&(objectClass=mailUser)(uid=diana))
Lock QC index = 0x7ee9fe8
Base of added query = dc=ciela.net,dc=hosting,dc=spnet,dc=net
QUERY ANSWERABLE (answered 63 times)
conn=3573 op=812 SEARCH RESULT tag=101 err=0 nentries=1 text=
slapd: /home/luben/openldap-2.4.18-h/servers/slapd/entry.c:483: 
entry_clean: Assertion `e->e_private == ((void *)0)' failed.

This sequence of :
query template of incoming query = (&(objectClass=)(uid=))
QUERY NOT ANSWERABLE
QUERY NOT CACHEABLE

is something I could not explain. There is not a log entry for incomming 
search. I have restarted the cache with more logging 
(stats+trace+pcache) to see from where they come.

I have some core dumps and if you tell me for what to look for, tomorrow 
I will debug them and see if there is a common pattern.

Luben