slapd memory footprint

[Stelios Grigoriadis <stelios.xx.grigoriadis@ericsson.com>]

After running some test we observed that slapd is consuming a 
considerable amount of memory, why is that? We ran one client that 
retrieved the entire tree (it was pretty small anyway) and 10 other 
clients that searched for a particular item. Comparing version 2.3.39 
with 2.3.32 the footprint increases. From top:

2.3.32:
 PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  SWAP CODE 
DATA COMMAND
6049 root      18   0  221m 4904 2568 S 11.5  0.2   0:33.27 216m 2844 
137m slapd

2.3.39:
 PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  SWAP CODE 
DATA COMMAND
13062 ldap      18   0  268m  80m  77m S 14.3 16.2   0:42.27 188m 2892 
185m slapd


Is this to be expected? By decreasing the cachesize we got:

 PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  SWAP CODE 
DATA COMMAND
22492 ldap      18   0  255m  80m  77m S 14.5 16.1   0:39.01 175m 2892 
172m slapd

which is still pretty big.

The whole ldap tree fits into a 14k large ldif file so the amount of 
data is not large. Is there any way we can influence the memory 
footprint (eg. by setting som parameter)?

/Stelios