fix(vlv): include contextID in subsequent VLV requests - #618
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The VLV request control did not encode the optional contextID field, even when it was present on the request control object. The LDAP server uses the contextID returned in a VLV response to continue an existing virtual list search. Omitting it causes each subsequent request to be treated as a new VLV search, preventing state reuse and leading to significantly increased processing time and memory usage on the LDAP server. Encode contextID whenever it is available to allow servers to resume an existing VLV search context as intended by RFC 3876. Co-Authored-By: Felix Botner <botner@univention.de>
mistotebe
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Aug 25, 2026
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LGTM
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We wondered about the performance and usage of the whole memory when using the VLV control in a request:
A environment with 200.000 users and 8 GB RAM:
normal LDAP search: 6.125s
SSS + VLV with PAGE_SIZE=50: aborted after 3-4 minutes, RAM completely full
SSS + VLV with PAGE_SIZE=2000: 1m36.634s (slapd Mem 65.7 %)
SimplePagedResultsControl PAGE_SIZE=50: 10.394s
SimplePagedResultsControl PAGE_SIZE=2000: 6.248s
The VLV request control did not encode the optional contextID field, even when it was present on the request control object.
The LDAP server uses the contextID returned in a VLV response to continue an existing virtual list search. Omitting it causes each subsequent request to be treated as a new VLV search, preventing state reuse and leading to significantly increased processing time and memory usage on the LDAP server.
Encode contextID whenever it is available to allow servers to resume an existing VLV search context as intended by RFC 3876.