IIUC, the reason you don't see any calls to sync() is because Solr's use of ZK is mostly based on Watchers? ... so we have callback functions to be notified anytime something (like leaeders, overseer, cluster state, etc...) changes and those calbacks update local copies of that state, which other (less zk savy) code can read on demand ... there shouldn't be much "polling" of ZK data in Solr that would require syncs?
: Date: Thu, 19 Apr 2018 21:16:41 +0000 : From: David Smiley <[email protected]> : Reply-To: [email protected] : To: "[email protected]" <[email protected]> : Subject: FYI Zookeeper.sync() : : As I was contemplating how it is that I see some weird behavior while : working on SolrCloud stuff could happen, I started to question my basic : assumptions. One assumption I held is that SolrZkClient.getData (which : calls ZooKeeper.getData) would always return the most up to date : information from the ZK cluster. The docs to ZooKeeper.getData say nothing : on this matter. If it did work this way, I imagine it would need to talk : to at least a majority of the ZK ensemble. Now that I reed the ZK : Programmer's guide RE consistency guarantees -- : http://zookeeper.apache.org/doc/r3.4.11/zookeeperProgrammers.html#ch_zkGuarantees : I : see reads may read stale data and that I can use ZooKeeper.sync() first to : get the latest. Okay wow. Interestingly we don't call this anywhere in : our codebase. With this newfound realization, I think at least one place : pertaining to TimeRoutedAliases really wants the most up to date : information, so I'll need to add a call to sync. Of course sync() should : be added deliberately not haphazardly; I'm sure it has overhead. : -- : Lucene/Solr Search Committer, Consultant, Developer, Author, Speaker : LinkedIn: http://linkedin.com/in/davidwsmiley | Book: : http://www.solrenterprisesearchserver.com : -Hoss http://www.lucidworks.com/ --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
