This page lists known issues with Hive 3 on MR3. Note that here we do not report known bugs in Apache Hive 3, whether fixed in Apache Hive 4 or not.
1. LOG_LEVEL in kubernetes/env.sh (on Kubernetes)
The environment variable LOG_LEVEL is used only for DAGAppMaster and ContainerWorkers.
LOG_LEVEL=INFO
To change the logging level for Metastore and HiveServer2,
update kubernetes/conf/hive-log4j2.properties.
2. Invalid cache of DynamicValue
If the user switches to another database and executes the same query again that has been executed previously,
a wrong result may be returned
because Hive internally uses the cache of DynamicValue populated with the previous database.
A practical workaround is to delete all running ContainerWorkers,
if the user intends to execute the same query again,
after switching to another database.
Alternatively the user can set the configuration key hive.io.sarg.cache.max.weight.mb to 0 in hive-site.xml
(which is not recommended).
3. GroupByOperator estimating memory usage
When multiple TaskAttempts run inside a DAGAppMaster in local mode,
GroupByOperator conservatively estimates the size of memory used by a TaskAttempt.
As a result, GroupByOperator flushes hash tables more often than necessary.
The user can mitigate this issue by increasing the value for the configuration key hive.map.aggr.hash.force.flush.memory.threshold in hive-site.xml.
