1 addpartial Overlay README
4 This package contains an OpenLDAP overlay called "addpartial" that
5 intercepts add requests, determines if the entry exists, determines what
6 attributes, if any, have changed, and modifies those attributes. If the
7 entry does not exist, the add request falls through and proceeds normally.
8 If the entry exists but no changes have been detected, the client receives
9 LDAP_SUCCESS (I suppose it is debatable what to do in this case, but this is
10 the most clean for my use. The LDAP_SUCCESS lets me know that the entry I
11 sent slapd == the entry already in my slapd DB. Perhaps this behavior
12 should be configurable in the future).
14 When a change is found, the addpartial overlay will replace all values for
15 the attribute (if an attribute does not exist in the new entry but exists
16 in the entry in the slapd DB, a replace will be done with an empty list of
19 Once a modify takes place, the addpartial overlay will write changes to the
20 replog (using the slap_replog_cb). If you are using syncrepl for
21 replication, the syncprov overlay will properly process the change, provided
22 that addpartial is the first overlay to run. Please see the CAVEATS for
23 more specifics about this.
25 The addpartial overlay makes it easy to replicate full entries to a slapd
26 instance without worrying about the differences between entries or even if
27 the entry exists. Using ldapadd to add entries, the addpartial overlay can
28 compare about 500 records per second. The intent of the addpartial overlay
29 is to make it easy to replicate records from a source that is not an LDAP
30 instance, such as a database. The overlay is also useful in places where it
31 is easier to create full entries rather than comparing an entry with an
32 entry that must be retrieved (with ldapsearch or similar) from an existing
33 slapd DB to find changes.
35 The addpartial overlay has been used in production since August 2004 and has
36 processed millions of records without incident.
39 A Makefile is included, please set your OPENLDAP_SRC directory properly.
42 After compiling the addpartial overlay, add the following to your
47 moduleload /path/to/addpartial-overlay.so
49 # after database directive...
50 # this overlay should be the last overlay in the config file to ensure that
51 # it properly intercepts the add request
57 - In order to ensure that addpartial does what it needs to do, it should be
58 the last overlay configured so it will run before the other overlays.
59 This is especially important if you are using syncrepl, as the modify that
60 addpartial does will muck with the locking that takes place in the