This bug is created as a clone of upstream ticket:
Heavily nested DIT LDIF files can take a long time when generating numsubordinates and ancestorIDs. There is no logging during these phases and it can appear that the import is hung.
There are also some internal "loops" in the import code that do not check for "aborts", and can actually hang the server if you attempt to stop it.
Hi Mark, could you provide the steps to verify?
Test that a shutdown aborts an online import
 Setup a DS instance using dc=example,dc=com
 Create a 300k entry ldif
 Run ldif2db.pl:
ldif2db.pl -Z INSTANCE -n userroot -D "cn=directory manager" -w Secret123 -i <LDIF FILE>
 Wait 5 seconds to allow the import to get started
 Stop the DS (this should not timeout or appear to "hang")
 Grep the errors log for "Aborting all Import threads"
$ rpm -qa | grep 389
I followed verification steps in #c4
$ grep Abort /var/log/dirsrv/slapd-rhel7ds/errors
[11/Dec/2014:00:58:45 +0100] - import userRoot: Aborting all Import threads...
Server didn't timeout or appear to hang.
Marking as VERIFIED.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.