Apache Solr Reference Guide Covering Apache Solr 6.0

1000
commitWithin
The commitWithin settings allow forcing document commits to happen in a defined time period. This is used
most frequently with Near Real Time Searching, and for that reason the default is to perform a soft commit. This
does not, however, replicate new documents to slave servers in a master/slave environment. If that's a
requirement for your implementation, you can force a hard commit by adding a parameter, as in this example:
false
With this configuration, when you call commitWithin as part of your update message, it will automatically
perform a hard commit every time.
Event Listeners
The UpdateHandler section is also where update-related event listeners can be configured. These can be
triggered to occur after any commit ( event="postCommit" ) or only after optimize commands ( event="postO
ptimize").
Users can write custom update event listener classes, but a common use case is to run external executables via
the RunExecutableListener:
Setting
exe
Description
The name of the executable to run. It should include the path to the file, relative to Solr home.
dir The directory to use as the working directory. The default is ".".
wait Forces the calling thread to wait until the executable returns a response. The default is true.
args
env
Any arguments to pass to the program. The default is none.
Any environment variables to set. The default is none.
Transaction Log
As described in the section RealTime Get, a transaction log is required for that feature. It is configured in the upd
ateHandler section of solrconfig.xml.
Realtime Get currently relies on the update log feature, which is enabled by default. It relies on an update log,
which is configured in solrconfig.xml, in a section like:
${solr.ulog.dir:}
Three additional expert-level configuration settings affect indexing performance and how far a replica can fall
behind on updates before it must enter into full recovery - see the section on write side fault tolerance for more
Apache Solr Reference Guide 6.0
451