ctubbsii commented on PR #2665:
URL: https://github.com/apache/accumulo/pull/2665#issuecomment-1155935221

   > > Having this as behavior with an explicit API method to configure isn't 
any different. A configured dispatcher could just ignore that configuration and 
dispatch to an eventually consistent ScanServer instead of a TabletServer.
   > 
   > That can not happen in this PR as its currently coded. When a scanner is 
set to immediate consistency the scan server dispatcher plugin is never 
consulted and only the tserver is used.
   
   So, there's two separate dispatching paths? And the path for the scan server 
bypasses the per-table configured dispatcher `table.scan.dispatcher`? That 
seems very confusing, especially since this PR adds new properties to configure 
`sserver.scan.executors`... but there's no way to select an executor via hints 
to a dispatcher? My understanding is that we wanted to try to mirror the 
tserver scan behavior as much as possible. Having two paths, without a 
dispatcher in the scan server path is very confusing. Have two paths, period, 
is very confusing. It just seems dramatically simpler to have a per-table 
dispatcher that is aware of scan servers and capable of dispatching to 
`sserver.scan.executors` (depending on hints) in addition to the usual 
`tserver.scan.executors`.
   
   Even if a dispatcher is added to the path for the scan server, it still 
seems far more complex than just relying on a single dispatcher... which also 
gives us the "enabled or disabled for a table" feature that Dave mentioned... 
because you can choose whether to configure a dispatcher that is scan server 
aware or not for a given table... without any new APIs.
   
   I'm probably completely misunderstanding how the dispatching changed in this 
PR. Is there a diagram or something to help illustrate the new dispatching 
design?


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