"At last, please let me ask another question, is it true that after every commit, even if I had only updated one document, the SolrCloud cache is invalidated (i.e. Solr must open a new searcher)? Because this what the second clients does, updating a document at time and commit. In other words, how is good/bad having multiple hard commit in a short time (few seconds)? "
Your affirmation is correct when you open a new Searcher. Caches are invalidated and possibly warmed up again (if you configured to do that). This is valid for both hard and soft commits when you open a new searcher. To have visibility you need to open a new searcher. Given that, I would definitely not recommend one commit ( even a soft commit which is lighter than an hard one, but still not for free) per document. The overhead will be consistent, especially if you update few documents per second. I would go with an auto hard and soft commit on the updater client as well. You can set up a timing between the commits which is compatible with the maximum latency you can accept for updates to show up. Solr gives support to Near Real Time search (through soft commits), and it is definitely possible to tune it for "seconds" updates, but I always recommend to start from the most acceptable latency in updates and then reduce it if necessary. I will mention again a very valid blog from Erick, which explains in detail the different type of commits : https://lucidworks.com/2013/08/23/understanding-transaction-logs-softcommit-and-commit-in-sorlcloud/ ----- --------------- Alessandro Benedetti Search Consultant, R&D Software Engineer, Director Sease Ltd. - www.sease.io -- Sent from: http://lucene.472066.n3.nabble.com/Solr-User-f472068.html
