The SERVER_NAME_LOOKUP_NO_UPDATE setting can be used in NOTES.INI to delay Domino Directory index updates. Doing so can remove bottle necks to accessing the directory, which can improved server response.
While the Update task is explicitly updating Domino Directory (names.nsf) views, any NameLookup or NIFFindByKey calls that need to access a view being updated will back up on the locked collection until the update is done.
Any threads waiting on a NameLookup call will wait because the collection is being updated. Thus, you will see this behavior in the form of hangs. For example, NRPC connections (which do a NameLookup for authentication) might either take extra time to complete or return saying 'server is not available'.
Unnecessary view updating can be suppressed with the use of DEBUG_ENABLE_UPDATE_FIX=MASK (where MASK can equal any bit pattern up to 0x1FFF) & SERVER_NAME_LOOKUP_NO_UPDATE=1. These settings should be used together.
When absent, Domino Directory views can be updated unnecessarily. This default behavior is equivalent to SERVER_NAME_LOOKUP_NO_UPDATE=0
Staring with Domino 8.0, this Domino Directory view update suppression is enabled by default.
DEBUG_ENABLE_UPDATE_FIX has the default value of 8191 (0x1FFF)
Set DEBUG_ENABLE_UPDATE_FIX=8191 (0x1FFF). You can consider setting it to some subset of the bits. Technote 1254752 recommends 8191. Technote 1244315 describes these bit options in detail.
Introduced for Domino 6.5.5 & 7.0.2.
Prior to 8.0.1 if SERVER_NAME_LOOKUP_NO_UPDATE is enabled, then DEBUG_ENABLE_UPDATE_FIX must also be set.
As of 8.0.1 if DEBUG_ENABLE_UPDATE_FIX is absent, the default behavior is as if it was set to 8191. DEBUG_ENABLE_UPDATE_FIX can still be used to override the default 8191 value.
No restart required. Changes to this setting will be detected within 5 minutes.
Currently in the Domino 7.0.3, 8 & 8.5 code streams, setting SERVER_NAME_LOOKUP_NO_UPDATE=1 will cause the server console to spit back "Server_Name_Lookup_Fail_Update went to 0". The message is annoying, but harmless. It's actually a very good idea to have Server_Name_Lookup_Fail_Update absent or disabled with a value of 0.
The value of Server_Name_Lookup_Fail_Update is incorrectly associated to an explicitly set value of SERVER_NAME_LOOKUP_NO_UPDATE. The following SPR has been created: "HPES7LRJHA: SERVER_NAME_LOOKUP_FAIL_UPDATE is incorrectly tired to Server_Name_Lookup_No_Update". This bug is expected to be fixed for Domino 7.0.4, 8.0.3 & 8.5.1, thereby removing the erroneous console message.
NameLookup performance fixes that address unnecessary updates
Domino server hangs after replicating Domino Directory
Domino Configuration Tuner:
This setting is included in the DCT catalog of best practices.
There is no kown UI setting for this notes.ini variable. But you can specify this setting in the notes.ini settings tab of the configuration settings document.
IBM Wiki: Server_Name_Lookup_Fail_Update notes.ini entry