Hi Gaurav 1.When you opened index to write,till you close that index, there will be a lock to do further write. But not for search. During merge, index needs 3X ( not sure 2X?) of more storage space, i believe that is the reason for no blocking for search. ( any other experts can clarify you more on this )
2. Merge will be taken care by default values( merge factor 2) of lucene. If u need to control more on merge policy, please go through about merge by size or by number of segments or many merge policies. Hope this will help you a little bit. -- Kumaran R Sent from Phone > On 04-Aug-2014, at 8:04 pm, Gaurav gupta <gupta.gaurav0...@gmail.com> wrote: > > Hi, > > We are planning to use Lucene 4.8.1 over Oracle (1 to 2 TB data) and > seeking information on "How Lucene conduct housekeeping or maintenance of > indexes over a period of time". *Is it a blocking operation for write and > search or it will not block anything while merging is going on? * > > I found :- *"Since Lucene adds the updated document to the index and marks > all previous versions as deleted. So to get rid of deleted documents Lucene > needs to do some housekeeping over a period of time. Under the hood is that > from time to time segments are merged into (usually) bigger segments > using configurable MergePolicy > <http://lucene.apache.org/java/3_4_0/api/core/org/apache/lucene/index/MergePolicy> > (TieredMergePolicy). > "* > > 1- Is it's a blocking operation for write and search both or it will not > block anything while merging is going on? > > 2- What is the best practice to avoid any blocking in production servers? > Not sure how Solr or Elasticsearch is handling it. > Should we control the merging by calling *forcemerge(int) at low traffic > time *to avoid any unpredictable blocking operation? Is it recommended or > Lucene do intelligent merging and don't block anything (updates and > searches) or there are ways to reduce the blocking time to a very small > duration (1 -2 minutes) using some API or demon thread etc. > > Looking for your professional guidance on it. > > Regards > Gaurav --------------------------------------------------------------------- To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org For additional commands, e-mail: java-user-h...@lucene.apache.org
