Task Resource

The Task resource provides a set of REST endpoints that give Presto servers the ability to communicate about tasks and task output. This isn’t a service that will be used by end users, but it supports the execution of queries on a Presto installation.

GET /v1/task()

Returns information about all tasks known to a Presto server.

Note that the output of a call to /v1/task can be quite large. If you execute this against a busy Presto server the response received will include a listing of every task known to that server along with detailed statistics about operators and drivers.

The following example response shows a trivial task response that has been truncated to fit this manual. A real response from a busy Presto server would generate pages and pages of output. Here there is a taskId for a task which is in the CANCELED state.

Example response:

  1. [ {
  2.   "taskId" : "20131222_183944_00011_dk5x2.1.0",
  3.   "version" : 9223372036854775807,
  4.   "state" : "CANCELED",
  5.   "self" : "unknown",
  6.   "lastHeartbeat" : "2013-12-22T13:54:46.566-05:00",
  7.   "outputBuffers" : {
  8.     "state" : "FINISHED",
  9.     "masterSequenceId" : 0,
  10.     "pagesAdded" : 0,
  11.     "buffers" : [ ]
  12.   },
  13.   "noMoreSplits" : [ ],
  14.   "stats" : {
  15.     "createTime" : "2013-12-22T13:54:46.566-05:00",
  16.     "elapsedTime" : "0.00ns",
  17.     "queuedTime" : "92.00us",
  18.     "totalDrivers" : 0,
  19.     "queuedDrivers" : 0,
  20.     "runningDrivers" : 0,
  21.     "completedDrivers" : 0,
  22.     "memoryReservation" : "0B",
  23.     "totalScheduledTime" : "0.00ns",
  24.     "totalCpuTime" : "0.00ns",
  25.     "totalBlockedTime" : "0.00ns",
  26.     "rawInputDataSize" : "0B",
  27.     "rawInputPositions" : 0,
  28.     "processedInputDataSize" : "0B",
  29.     "processedInputPositions" : 0,
  30.     "outputDataSize" : "0B",
  31.     "outputPositions" : 0,
  32.     "pipelines" : [ ]
  33.   },
  34.   "failures" : [ ],
  35.   "outputs" : { }
  36. }]

POST /v1/task/{taskId}()

DELETE /v1/task/{taskId}()

Deletes a given task from a Presto server.

GET /v1/task/{taskId}()

Retrieves information about a specific task by taskId.

The following example lists the output of a task. It contains the following high-level sections:

  • outputBuffers

  • noMoreSplits

  • stats

  • failures

  • outputs

This is the same output that is also present in the response from the Query resource which lists all of the stages and tasks involved in a particular query. This is call is used by Presto to coordinate a queries.

Example response:

  1. {
  2.   "taskId" : "20140115_170528_00004_dk5x2.0.0",
  3.   "version" : 42,
  4.   "state" : "FINISHED",
  5.   "self" : "http://10.193.207.128:8080/v1/task/20140115_170528_00004_dk5x2.0.0",
  6.   "lastHeartbeat" : "2014-01-15T12:12:12.518-05:00",
  7.   "outputBuffers" : {
  8.     "state" : "FINISHED",
  9.     "masterSequenceId" : 0,
  10.     "pagesAdded" : 1,
  11.     "buffers" : [ {
  12.       "bufferId" : "out",
  13.       "finished" : true,
  14.       "bufferedPages" : 0,
  15.       "pagesSent" : 1
  16.     } ]
  17.   },
  18.   "noMoreSplits" : [ "8" ],
  19.   "stats" : {
  20.     "createTime" : "2014-01-15T12:12:08.520-05:00",
  21.     "startTime" : "2014-01-15T12:12:08.526-05:00",
  22.     "endTime" : "2014-01-15T12:12:12.518-05:00",
  23.     "elapsedTime" : "4.00s",
  24.     "queuedTime" : "6.39ms",
  25.     "totalDrivers" : 1,
  26.     "queuedDrivers" : 0,
  27.     "runningDrivers" : 0,
  28.     "completedDrivers" : 1,
  29.     "memoryReservation" : "174.76kB",
  30.     "totalScheduledTime" : "4.19ms",
  31.     "totalCpuTime" : "4.09ms",
  32.     "totalBlockedTime" : "29.50ms",
  33.     "rawInputDataSize" : "10.90kB",
  34.     "rawInputPositions" : 154,
  35.     "processedInputDataSize" : "10.90kB",
  36.     "processedInputPositions" : 154,
  37.     "outputDataSize" : "10.90kB",
  38.     "outputPositions" : 154,
  39.     "pipelines" : [ {
  40.       "inputPipeline" : true,
  41.       "outputPipeline" : true,
  42.       "totalDrivers" : 1,
  43.       "queuedDrivers" : 0,
  44.       "runningDrivers" : 0,
  45.       "completedDrivers" : 1,
  46.       "memoryReservation" : "0B",
  47.       "queuedTime" : {
  48.         "maxError" : 0.0,
  49.         "count" : 1.0,
  50.         "total" : 5857000.0,
  51.         "p01" : 5857000,
  52.         "p05" : 5857000,
  53.         "p10" : 5857000,
  54.         "p25" : 5857000,
  55.         "p50" : 5857000,
  56.         "p75" : 5857000,
  57.         "p90" : 5857000,
  58.         "p95" : 5857000,
  59.         "p99" : 5857000,
  60.         "min" : 5857000,
  61.         "max" : 5857000
  62.       },
  63.       "elapsedTime" : {
  64.         "maxError" : 0.0,
  65.         "count" : 1.0,
  66.         "total" : 4.1812E7,
  67.         "p01" : 41812000,
  68.         "p05" : 41812000,
  69.         "p10" : 41812000,
  70.         "p25" : 41812000,
  71.         "p50" : 41812000,
  72.         "p75" : 41812000,
  73.         "p90" : 41812000,
  74.         "p95" : 41812000,
  75.         "p99" : 41812000,
  76.         "min" : 41812000,
  77.         "max" : 41812000
  78.       },
  79.       "totalScheduledTime" : "4.19ms",
  80.       "totalCpuTime" : "4.09ms",
  81.       "totalBlockedTime" : "29.50ms",
  82.       "rawInputDataSize" : "10.90kB",
  83.       "rawInputPositions" : 154,
  84.       "processedInputDataSize" : "10.90kB",
  85.       "processedInputPositions" : 154,
  86.       "outputDataSize" : "10.90kB",
  87.       "outputPositions" : 154,
  88.       "operatorSummaries" : [ {
  89.         "operatorId" : 0,
  90.         "operatorType" : "ExchangeOperator",
  91.         "addInputCalls" : 0,
  92.         "addInputWall" : "0.00ns",
  93.         "addInputCpu" : "0.00ns",
  94.         "addInputUser" : "0.00ns",
  95.         "inputDataSize" : "10.90kB",
  96.         "inputPositions" : 154,
  97.         "getOutputCalls" : 1,
  98.         "getOutputWall" : "146.00us",
  99.         "getOutputCpu" : "137.90us",
  100.         "getOutputUser" : "0.00ns",
  101.         "outputDataSize" : "10.90kB",
  102.         "outputPositions" : 154,
  103.         "blockedWall" : "29.50ms",
  104.         "finishCalls" : 0,
  105.         "finishWall" : "0.00ns",
  106.         "finishCpu" : "0.00ns",
  107.         "finishUser" : "0.00ns",
  108.         "memoryReservation" : "0B",
  109.         "info" : {
  110.           "bufferedBytes" : 0,
  111.           "averageBytesPerRequest" : 11158,
  112.           "bufferedPages" : 0,
  113.           "pageBufferClientStatuses" : [ {
  114.             "uri" : "http://10.193.207.128:8080/v1/task/20140115_170528_00004_dk5x2.1.0/results/ab68e201-3878-4b21-b6b9-f6658ddc408b",
  115.             "state" : "closed",
  116.             "lastUpdate" : "2014-01-15T12:12:08.562-05:00",
  117.             "pagesReceived" : 1,
  118.             "requestsScheduled" : 3,
  119.             "requestsCompleted" : 3,
  120.             "httpRequestState" : "queued"
  121.           } ]
  122.         }
  123.       }, {
  124.         "operatorId" : 1,
  125.         "operatorType" : "FilterAndProjectOperator",
  126.         "addInputCalls" : 1,
  127.         "addInputWall" : "919.00us",
  128.         "addInputCpu" : "919.38us",
  129.         "addInputUser" : "0.00ns",
  130.         "inputDataSize" : "10.90kB",
  131.         "inputPositions" : 154,
  132.         "getOutputCalls" : 2,
  133.         "getOutputWall" : "128.00us",
  134.         "getOutputCpu" : "128.64us",
  135.         "getOutputUser" : "0.00ns",
  136.         "outputDataSize" : "10.45kB",
  137.         "outputPositions" : 154,
  138.         "blockedWall" : "0.00ns",
  139.         "finishCalls" : 5,
  140.         "finishWall" : "258.00us",
  141.         "finishCpu" : "253.19us",
  142.         "finishUser" : "0.00ns",
  143.         "memoryReservation" : "0B"
  144.       }, {
  145.         "operatorId" : 2,
  146.         "operatorType" : "OrderByOperator",
  147.         "addInputCalls" : 1,
  148.         "addInputWall" : "438.00us",
  149.         "addInputCpu" : "439.18us",
  150.         "addInputUser" : "0.00ns",
  151.         "inputDataSize" : "10.45kB",
  152.         "inputPositions" : 154,
  153.         "getOutputCalls" : 4,
  154.         "getOutputWall" : "869.00us",
  155.         "getOutputCpu" : "831.85us",
  156.         "getOutputUser" : "0.00ns",
  157.         "outputDataSize" : "10.45kB",
  158.         "outputPositions" : 154,
  159.         "blockedWall" : "0.00ns",
  160.         "finishCalls" : 4,
  161.         "finishWall" : "808.00us",
  162.         "finishCpu" : "810.18us",
  163.         "finishUser" : "0.00ns",
  164.         "memoryReservation" : "174.76kB"
  165.       }, {
  166.         "operatorId" : 3,
  167.         "operatorType" : "FilterAndProjectOperator",
  168.         "addInputCalls" : 1,
  169.         "addInputWall" : "166.00us",
  170.         "addInputCpu" : "166.66us",
  171.         "addInputUser" : "0.00ns",
  172.         "inputDataSize" : "10.45kB",
  173.         "inputPositions" : 154,
  174.         "getOutputCalls" : 5,
  175.         "getOutputWall" : "305.00us",
  176.         "getOutputCpu" : "241.14us",
  177.         "getOutputUser" : "0.00ns",
  178.         "outputDataSize" : "10.90kB",
  179.         "outputPositions" : 154,
  180.         "blockedWall" : "0.00ns",
  181.         "finishCalls" : 2,
  182.         "finishWall" : "70.00us",
  183.         "finishCpu" : "71.02us",
  184.         "finishUser" : "0.00ns",
  185.         "memoryReservation" : "0B"
  186.       }, {
  187.         "operatorId" : 4,
  188.         "operatorType" : "TaskOutputOperator",
  189.         "addInputCalls" : 1,
  190.         "addInputWall" : "50.00us",
  191.         "addInputCpu" : "51.03us",
  192.         "addInputUser" : "0.00ns",
  193.         "inputDataSize" : "10.90kB",
  194.         "inputPositions" : 154,
  195.         "getOutputCalls" : 0,
  196.         "getOutputWall" : "0.00ns",
  197.         "getOutputCpu" : "0.00ns",
  198.         "getOutputUser" : "0.00ns",
  199.         "outputDataSize" : "10.90kB",
  200.         "outputPositions" : 154,
  201.         "blockedWall" : "0.00ns",
  202.         "finishCalls" : 1,
  203.         "finishWall" : "35.00us",
  204.         "finishCpu" : "35.39us",
  205.         "finishUser" : "0.00ns",
  206.         "memoryReservation" : "0B"
  207.       } ],
  208.       "drivers" : [ ]
  209.     } ]
  210.   },
  211.   "failures" : [ ],
  212.   "outputs" : { }
  213. }

GET /v1/task/{taskId}/results/{outputId}/{token}()

This service is used by Presto to retrieve task output.

DELETE /v1/task/{taskId}/results/{outputId}()

This service is used by Presto to delete task output.