10.5. Resource Group Configuration

Note

Resource groups are currently experimental and must be enabled with the experimental.resource-groups-enabled=true config flag.

Resource groups place limits on resource usage, and can enforce queueing policies on queries that run within them or divide their resources among sub groups. A query belongs to a single resource group, and consumes resources from that group (and its ancestors). Except for the limit on queued queries, when a resource group runs out of a resource it does not cause running queries to fail; instead new queries become queued. A resource group may have sub groups or may accept queries, but may not do both.

The resource groups and associated selection rules are configured by a manager which is pluggable. An implementation that uses a static file can be installed via the presto-resource-group-managers plugin and enabled by adding resource-groups.configuration-manager=file to etc/resource-groups.properties and setting resource-groups.config-file to the location of a JSON config file with the properties described below.

Resource Group Properties

  • name (required): name of the group. May be a template (see below).

  • maxQueued (required): maximum number of queued queries. Once this limit is reached new queries will be rejected.

  • maxRunning (required): maximum number of running queries.

  • softMemoryLimit (required): maximum amount of distributed memory this group may use before new queries become queued. May be specified as an absolute value (i.e. 1GB) or as a percentage (i.e. 10%) of the cluster’s memory.

  • softCpuLimit (optional): maximum amount of CPU time this group may use in a period (see cpuQuotaPeriod) before a penalty will be applied to the maximum number of running queries. hardCpuLimit must also be specified.

  • hardCpuLimit (optional): maximum amount of CPU time this group may use in a period.

  • schedulingPolicy (optional): specifies how queued queries are selected to run, and how sub groups become eligible to start their queries. May be one of three values:

    • fair (default): queued queries are processed first-in-first-out, and sub groups must take turns starting new queries (if they have any queued).
    • weighted: queued queries are selected stochastically in proportion to their priority (specified via the query_priority session property). Sub groups are selected to start new queries in proportion to their schedulingWeight.
    • query_priority: all sub groups must also be configured with query_priority. Queued queries will be selected strictly according to their priority.

  • schedulingWeight (optional): weight of this sub group. See above. Defaults to 1.

  • jmxExport (optional): If true, group statistics are exported to JMX for monitoring. Defaults to false.

  • subGroups (optional): list of sub groups.

Selector Properties

  • user (optional): regex to match against user name. Defaults to .*
  • source (optional): regex to match against source string. Defaults to .*
  • group (required): the group these queries will run in.

Global Properties

  • cpuQuotaPeriod (optional): the period in which cpu quotas are enforced.

Selectors are processed sequentially and the first one that matches will be used. In the example configuration below, there are five resource group templates. In the adhoc_${USER} group, ${USER} will be expanded to the name of the user that submitted the query. ${SOURCE} is also supported, which expands to the source submitting the query. The source name can be set as follows:

  • CLI: use the --source option.
  • JDBC: set the ApplicationName client info property on the Connection instance.

There are three selectors that define which queries run in which resource group:

  • The first selector places queries from bob into the admin group.
  • The second selector states that all queries that come from a source that includes “pipeline” should run in the user’s personal pipeline group, which belongs to the global.pipeline parent group.
  • The last selector is a catch all, which puts all queries into the user’s adhoc group.

All together these selectors implement the policy that bob is an admin and all other users are subject to the following limits:

  • Users are allowed to have up to 2 adhoc queries running. Additionally, they may run one pipeline.
  • No more than 5 “pipeline” queries may run at once.
  • No more than 100 total queries may run at once, unless they’re from the admin.
{
  "rootGroups": [
    {
      "name": "global",
      "softMemoryLimit": "80%",
      "maxRunning": 100,
      "maxQueued": 1000,
      "schedulingPolicy": "weighted",
      "jmxExport": true,
      "subGroups": [
        {
          "name": "adhoc_${USER}",
          "softMemoryLimit": "10%",
          "maxRunning": 2,
          "maxQueued": 1,
          "schedulingWeight": 9,
          "schedulingPolicy": "query_priority"
        },
        {
          "name": "pipeline",
          "softMemoryLimit": "20%",
          "maxRunning": 5,
          "maxQueued": 100,
          "schedulingWeight": 1,
          "jmxExport": true,
          "subGroups": [
            {
              "name": "pipeline_${USER}",
              "softMemoryLimit": "10%",
              "maxRunning": 1,
              "maxQueued": 100,
              "schedulingPolicy": "query_priority"
            }
          ]
        }
      ]
    },
    {
      "name": "admin",
      "softMemoryLimit": "100%",
      "maxRunning": 200,
      "maxQueued": 100,
      "schedulingPolicy": "query_priority",
      "jmxExport": true
    }
  ],
  "selectors": [
    {
      "user": "bob",
      "group": "admin"
    },
    {
      "source": ".*pipeline.*",
      "group": "global.pipeline.pipeline_${USER}"
    },
    {
      "group": "global.adhoc_${USER}"
    }
  ],
  "cpuQuotaPeriod": "1h"
}