Memory Configuration in Presto Cluster

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Presto cluster is sensitive to memory setup. As Presto is developed in Java, Java is foundation to configure it. In many cases, Presto server is not started because of memory configuration. During Presto server launch, the validation rules are applied to make sure that major memory settings are consistent. It does not guarantee of cluster stability and performance so spending time on initial memory setup can contribute to success of your cluster.

The article is based on CentOS 7 environment and Starburst version 332-e.1.

Disable Linux swap

Presto assumes that memory swap is disabled and is not mounted.

The current swappiness setting can be received.

cat /proc/sys/vm/swappiness

Turn off swappiness temporary.

sudo sysctl vm.swappiness=0

Turn off swappiness permanently changing vm.swappiness=0 setting in the file below.

sudo nano /etc/sysctl.conf

Swap memory information.

free -h

Output

              total        used        free      shared  buff/cache   available
Mem:           503G        182G        297G         10M         23G        319G
Swap:            0B          0B          0B

JVM configuration

The setting is defined in jvm.config file. It should be set up 70-80% of a server physical memory. If you are tough on resources, it can be at least 12GB less than physical memory. The more setting value is set up, the less stable system you get.

-Xmx480G

Default Presto configuration

The list of memory settings are below. If any value is skipped, it is taken as the default one.

query.max-memory-per-node
Default value: JVM max memory * 0.1
Description: Max amount of user memory a query can use on a worker.

query.max-total-memory-per-node
Default value: JVM max memory * 0.3
Description: Max amount of user and system memory a query can use on a worker.

query.max-memory
Default value: 20GB
Description: Max amount of user memory a query can use across the entire cluster.

query.max-total-memory
Default value: query.max-memory * 2
Description: Max amount of user and system memory a query can use across the entire cluster.

memory.heap-headroom-per-node
Default value: JVM max memory * 0.3
Description: Amount of memory set aside as headroom/buffer in the JVM heap for allocations that are not tracked by Presto.

Basic memory setup

  • Physical memory: 512GB
  • Workers: 10
  • JVM Xmx: physical memory * 70% = 358GB
  • query.max-memory-per-node: JVM Xmx * 0.5 = 179GB
  • query.max-total-memory-per-node: query.max-memory-per-node * 1.2 = 214GB
  • memory.heap-headroom-per-node: 50GB
  • query.max-memory: workers * query.max-memory-per-node = 1,790GB
  • query.max-total-memory: workers * query.max-total-memory-per-node = 2,140GB

Highly concurrent memory setup

  • Physical memory: 512GB
  • Workers: 10
  • JVM Xmx: physical memory * 70% = 358GB
  • query.max-memory-per-node: JVM Xmx * 0.1 = 36GB
  • query.max-total-memory-per-node: query.max-memory-per-node * 1.2 = 43GB
  • memory.heap-headroom-per-node = 50GB
  • query.max-memory: workers * query.max-memory-per-node = 360GB
  • query.max-total-memory: workers * query.max-total-memory-per-node = 430GB

Large data skew memory setup

  • Physical memory: 512GB
  • Workers: 10
  • JVM Xmx: physical memory * 80% = 410GB
  • query.max-memory-per-node: JVM Xmx * 0.7 = 287GB
  • query.max-total-memory-per-node: query.max-memory-per-node * 1.2 = 344GB
  • memory.heap-headroom-per-node = 30GB
  • query.max-memory: workers * query.max-memory-per-node = 2,870GB
  • query.max-total-memory: workers * query.max-total-memory-per-node = 3,440GB

Validation rule

JVM Xmx > query.max-total-memory-per-node + memory.heap-headroom-per-node

Killer policy in case of out of memory

Out of memory (OOM) is customizable. The setting is query.low-memory-killer.policy.

Spill to disk

OOM can be mitigated if spilling memory to disk is enabled. It does not cover all possible cases. The configuration file is config.properties. For example,

experimental.max-spill-per-node=500GB
experimental.query-max-spill-per-node=200GB
experimental.spill-enabled=true
experimental.spiller-spill-path=/mnt/presto/data/spill

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