Questions about OpenLDAP2.2~ release

[ZhangPu <zhang@fjh.fujitsu.com>]

Hello,

I've read the administration guide. 
Here questions about OpenLDAP2.2~ release.

In section "14. LDAP Sync Replication": 
-----------
While slapd (8) can function as the LDAP Sync provider only when it is configured 
with either back-bdb or back-hdb backend, the syncrepl engine, which is a 
consumer-side replication engine, can work with any backends.
-----------
Does this mean function "LDAP Syncrep" only can be applied with back-bdb/back-hdb? 
It cannot be supported with other backends? (For example, back-sql and etc.)

In section "15. The Proxy Cache Engine", also it wrote:
-----------
The <DB> parameter specifies which underlying database is to be used to hold cached 
entries. It should be set to bdb, hdb, or ldbm.
-----------
Does this mean function "Proxy Cache" only can be executed on back-bdb/hdb/ldbm?
It cannot be supported with other backends? 

If the answer is "yes", about the following new functions of 2.2~ version, are there 
other items only can be applied with back-bdb/hdb/ldb?
-------------------------------------------
"LDAP Sync"-based lightweight replication
Proxy Cache Support
Hierarchical Backend
NS-SLAPI Support
Backend Layering
Access Control extensions including dynamic group support
LDAPv3 extensions:
	ACID extensions
	Cancel Operation
	Content Synchronization Operation
	DIT Content Rules
	Duplicate Entry Extension
	Simple Paged Results Extension
	Proxy Authorization Extension
-------------------------------------------

Best regards.
Thanks
+------------------------------------------------------------+
 Zhang Pu zhang@fjh.fujitsu.com