Hive LLAP Overview

The overview dashboard shows the aggregated information across all of the clusters: for example, the total cache memory from all the nodes.

This dashboard enables you to see that your cluster is configured and running correctly. For example, you might have configured 10 nodes but you see only 8 nodes running. If you find an issue by viewing this dashboard, you can open the LLAP Daemon dashboard to see which node is having the problem.

Table 1. HIVE LLAP Overview metrics descriptions
Row	Metrics	Description
OVERVIEW	Total Executor Threads	Shows the total number of executors across all nodes.
	Total Executor Memory	Shows the total amount of memory for executors across all nodes.
	Total Cache Memory	Shows the total amount of memory for cache across all nodes.
	Total JVM Memory	Shows the total amount of max Java Virtual Machine (JVM) memory across all nodes.
CACHE METRICS ACROSS ALL NODES	Total Cache Usage	Shows the total amount of cache usage (Total, Remaining, and Used) across all nodes.
	Average Cache Hit Rate	As the data is released from the cache, the curve should increase. For example, the first query should run at 0, the second at 80-90 seconds, and then the third 10% faster. If, instead, it decreases, there might be a problem in the cluster.
	Average Cache Read Requests	Shows how many requests are being made for the cache and how many queries you are able to run that make use of the cache. If it says 0, for example, your cache might not be working properly and this grid might reveal a configuration issue.
CACHE METRICS ACROSS ALL NODES	Total Cache Usage	Shows the total amount of cache usage (Total, Remaining, and Used) across all nodes.
	Average Cache Hit Rate	As the data is released from the cache, the curve should increase. For example, the first query should run at 0, the second at 80-90 seconds, and then the third 10% faster. If, instead, it decreases, there might be a problem in the cluster.
	Average Cache Read Requests	Shows how many requests are being made for the cache and how many queries you are able to run that make use of the cache. If it says 0, for example, your cache might not be working properly and this grid might reveal a configuration issue.
EXECUTOR METRICS ACROSS ALL NODES	Total Executor Requests	Shows the total number of task requests that were handled, succeeded, failed, killed, evicted and rejected across all nodes. Handled: Total requests across all sub-groups Succeeded: Total requests that were processed. For example, if you have 8 core machines, the number of total executor requests would be 8 Failed: Did not complete successfully because, for example, you ran out of memory Rejected: If all task priorities are the same, but there are still not enough slots to fulfill the request, the system will reject some tasks Evicted: Lower priority requests are evicted if the slots are filled by higher priority requests
	Total Execution Slots	Shows the total execution slots, the number of free or available slots, and number of slots occupied in the wait queue across all nodes. Ideally, the threads available (blue) result should be the same as the threads that are occupied in the queue result.
	Time to Kill Pre-empted Task (300s interval)	Shows the time that it took to kill a query due to pre-emption in percentile (50th, 90th, 99th) latencies in 300 second intervals.
	Max Time To Kill Task (due to preemption)	Shows the maximum time taken to kill a task due to pre-emption. This grid and the one above show you if you are wasting a lot of time killing queries. Time lost while a task is waiting to be killed is time lost in the cluster. If your max time to kill is high, you might want to disable this feature.
	Pre-emption Time Lost (300s interval)	Shows the time lost due to pre-emption in percentile (50th, 90th, 99th) latencies in 300 second intervals.
	Max Time Lost In Cluster (due to pre-emption)	Shows the maximum time lost due to pre-emption. If your max time to kill is high, you might want to disable this feature.
IO ELEVATOR METRICS ACROSS ALL NODES	Column Decoding Time (30s interval)	Shows the percentile (50th, 90th, 99th) latencies for time it takes to decode the column chunk (convert encoded column chunk to column vector batches for processing) in 30 second intervals. The cache comes from IO Elevator. It loads data from HDFS to the cache, and then from the cache to the executor. This metric shows how well the threads are performing and is useful to see that the threads are running.
IO ELEVATOR METRICS ACROSS ALL NODES	Max Column Decoding Time	Shows the maximum time taken to decode column chunk (convert encoded column chunk to column vector batches for processing).
JVM METRICS ACROSS ALL NODES	Average JVM Heap Usage	Shows the average amount of Java Virtual Machine (JVM) heap memory used across all nodes. If the heap usage keeps increasing, you might run out of memory and the task failure count would also increase.
	Average JVM Non-Heap Usage	Shows the average amount of JVM non-heap memory used across all nodes.
	Max GcTotalExtraSleepTime	Shows the maximum garbage collection extra sleep time in milliseconds across all nodes. Garbage collection extra sleep time measures when the garbage collection monitoring is delayed (for example, the thread does not wake up after 500 milliseconds).
	Max GcTimeMillis	Shows the total maximum GC time in milliseconds across all nodes.
	Total JVM Threads	Shows the total number of JVM threads that are in a NEW, RUNNABLE, WAITING, TIMED_WAITING, and TERMINATED state across all nodes.
JVM METRICS	Total JVM Heap Used	Shows the total amount of Java Virtual Machine (JVM) heap memory used in the daemon. If the heap usage keeps increasing, you might run out of memory and the task failure count would also increase.
	Total JVM Non-Heap Used	Shows the total amount of JVM non-heap memory used in the LLAP daemon. If the non-heap memory is over-allocated, you might run out of memory and the task failure count would also increase.
	Max GcTotalExtraSleepTime	Shows the maximum garbage collection extra sleep time in milliseconds in the LLAP daemon. Garbage collection extra sleep time measures when the garbage collection monitoring is delayed (for example, the thread does not wake up after 500 milliseconds).
	Max GcTimeMillis	Shows the total maximum GC time in milliseconds in the LLAP daemon.
	Max JVM Threads Runnable	Shows the maximum number of Java Virtual Machine (JVM) threads that are in RUNNABLE state.
	Max JVM Threads Blocked	Shows the maximum number of JVM threads that are in BLOCKED state. If you are seeing spikes in the threads blocked, you might have a problem with your LLAP daemon.
	Max JVM Threads Waiting	Shows the maximum number of JVM threads that are in WAITING state.
	Max JVM Threads Timed Waiting	Shows the maximum number of JVM threads that are in TIMED_WAITING state.