Appendix I. Tuning DB2 UDB in the IBM LDAP Environment

Appendix I. Tuning DB2 UDB in the IBM LDAP Environment

This appendix describes some performance and tuning tips for DB2 UDB ESE in the IBM LDAP environment.

  • On a multi-processor AIX machine set MALLOCMULTIHEAP to the number of processor before starting LDAP. For example, to set the heap on a machine with eight processors:

    $ export MALLOCMULTIHEAP=heaps:8
  • Adjust the value of SHEAPTHRES parameter. This would help only if you are using fuzzy searches, search filters with Boolean operators, etc. Use database monitor to see whether your sort heap is exceeding its limit.

  • Adjust the value of BUFFPAGE parameter.

  • Adjust the value of DBHEAP parameter.

  • Adjust the value of SORTHEAP parameter.

  • Adjust the value of MAXLOCKS parameter.

  • Create index all attributes that you want to use in a search. Indexes are defined in LDAP schema files.

  • Perform REORGCHK, REORT, RUNSTATS, or REBIND as necessary after a large number of update, insert, or delete activities.

  • Enable LDAP concurrent read/write (by default, the current read/write is disabled).

For version 3.1 or earlier:


For version 3.2 or later:

  • Increase the entry cache size. The effectiveness of your LDAP cache depends on your workload. If your workload makes multiple requests for the same entry within a short period of time, bigger cache size might help. By default, the entry cache size is 1,000 (meaning it will cache 1,000 entries). To set the size to a different value, set RDBM_CACHE_SIZE to that value.

  • Disable the access control cache if and only if the clients bind as the LDAP administrator. If your application binds to the LDAP server as the LDAP administrator (which frequently is the case), the access control cache is not used. To turn off the access control cache, set ACLCACHE to NO; default is YES.

    $ set ACLCACHE=NO
  • If clients bind as individual users, do not turn the access control cache off. You may change its size by setting ACLCACHESIZE (default is RDBM_CACHE_SIZE).