[infinispan-issues] [Red Hat JIRA] (ISPN-12128) Remote read during state transfer should store entry in data container

Remote read during state transfer should store entry in data container ---------------------------------------------------------------------- Key: ISPN-12128 URL: https://issues.redhat.com/browse/ISPN-12128 Project: Infinispan Issue Type: Bug Components: Core, State Transfer Affects Versions: 11.0.1.Final Reporter: Dan Berindei Assignee: Dan Berindei Priority: Minor Fix For: 12.1.0.Final A cache with {{await-initial-transfer="false"}} will execute cache operations while it is receiving state, during rebalance phase {{READ_OLD_WRITE_ALL}}. State transfer can take a long time, and during that time, it is not a read owner for any segments, it is only a write owner for the segments it is receiving. That means {{cache.get(k)}} will perform a remote lookup every time, even AFTER the node received entry {{k=v}} via transfer, as long as not all the nodes have confirmed the end of state transfer and the coordinator hasn't changed the rebalance phase to {{READ_ALL_WRITE_ALL}}. The extra remote lookups can have a negative impact on application performance. Especially in a replicated cache, the application would expect reads to be very fast, and the repeated remote lookups would break that assumption. In order to encourage {{await-initial-transfer="false"}} and eventually make it the default (ISPN-9112), we should limit the number of remote lookups performed by a node while is is a write-only owner of a key: * Remote reads should write the entry in the data container, the same way state transfer would (i.e. skipping the write if a write operation already changed the entry). * Reads should first look up the key in the local data container before going remotely. If the key exists locally, the value can be returned directly.