Re: (ITS#6200) slapd crashes under load w/ syncrepl

[joacim.breiler@hgo.se]

We are trying out the 2.4.18 release with a syncrepl Multi-Master setup 
and are experiencing similar problems as mentioned above.

It will shut down with a segfault after heavy processing/updating of 
about 3000-17000 entries. We can reproduce this in about 10-20 minutes 
of heavy load. However, in this short execution time we can't find any 
signs of memory leakage.

Unfortunatly I can't get any good tracebacks from gdb. I've tried 
compiling openldap with:
export CPPFLAGS="-D_GNU_SOURCE -g". And also --enable-debug with 
/configure. Any pointers?

This is the traceback I get, but I guess it isn't very helpful without 
the complete debugging information:

(gdb) where
#0  0x00007fc7e24fb8eb in syncprov_op_mod (op=0x7fc7aedb37d0, rs=<value 
optimized out>) at syncprov.c:1970
#1  0x000000000049531a in overlay_op_walk ()
#2  0x0000000000495e7a in ?? ()
#3  0x000000000044a2e2 in fe_op_modify ()
#4  0x000000000044ac67 in do_modify ()
#5  0x00000000004321bf in ?? ()
#6  0x0000000000432e6c in ?? ()
#7  0x00000000004dd960 in ?? ()
#8  0x00007fc7e2e9b3ea in start_thread () from /lib/libpthread.so.0
#9  0x00007fc7e29f3cbd in clone () from /lib/libc.so.6
#10 0x0000000000000000 in ?? ()
(gdb)

Could these problems be related? And is there something we can do to 
help resolve it?

Regards,
Joacim Breiler



Configuration:

dn: olcDatabase={1}hdb,cn=config
objectClass: olcDatabaseConfig
objectClass: olcHdbConfig
olcDatabase: {1}hdb
olcDbDirectory: /srv/ldap
olcSuffix: dc=hgo,dc=se
olcAccess: {0}to attrs=userPassword,shadowLastChange by dn="cn=admin,dc=hgo,
 dc=se" write by anonymous auth by self write by * none
olcLastMod: TRUE
olcRootDN: cn=admin,dc=hgo,dc=se
olcRootPW: xxxxxxxx
olcSizeLimit: -1
olcSyncrepl: {0}rid=004 provider=ldap://diablo binddn="cn=admin,dc=hgo,dc=se
 " bindmethod=simple credentials="xxxxxxx" searchbase="dc=hgo,dc=se" ty
 pe=refreshAndPersist retry="5 5 300 5" timeout=1
olcSyncrepl: {1}rid=003 provider=ldap://mephisto binddn="cn=admin,dc=hgo,dc=
 se" bindmethod=simple credentials="xxxxxxx" searchbase="dc=hgo,dc=se"
 type=refreshAndPersist retry="5 5 300 5" timeout=1
olcMirrorMode: TRUE
olcDbCheckpoint: 2048 5
olcDbIDLcacheSize: 90000
olcDbIndex: objectClass,entryCSN,entryUUID,cn eq
olcDbCacheSize: 10000
olcDbConfig: {0}set_cachesize 1 0 0
olcDbConfig: {1}set_lk_max_objects 32000
olcDbConfig: {2}set_lk_max_locks 32000
olcDbConfig: {3}set_lk_max_lockers 1500
olcDbConfig: {4}set_flags DB_LOG_AUTOREMOVE
olcDbConfig: {5}set_lg_bsize 104857600
olcDbConfig: {6}set_lg_dir /srv/ldap