Hello. I am trying to figure out a quick way to query features that are on a feature service or map service so that I can go on to create visualizations from them. Feature services have a limit of how many records you can query at once. This limit is usually 1000. So, as a result I have to keep re-querying until I have all records. So far one way I found to do this is using QueryTask. However it seems quite slow compared to operations dashboard. Is this a bad approach? Here is my current method for querying records: html > head > meta name = " description " content = " DevLav: Query a feature layer " > meta charset = " utf-8 " > meta name = " viewport " content = " initial-scale = 1,maximum-scale = 1,user-scalable = no " > title > Query All using QueryTask title > style > html, body, #viewDiv { padding : 0 ; margin : 0 ; height : 100% ; width : 100% ; } style > link rel = " stylesheet " href = " https://js.arcgis.com/4.11/esri/css/main.css " > script src = " https://js.arcgis.com/4.11/ " > script > head > script > require ( [ "esri/Map" , "esri/views/MapView" , "esri/tasks/support/Query" , "esri/tasks/QueryTask" , "esri/Graphic" , "dojo/domReady!" ] , function ( Map , MapView , Query , QueryTask , Graphic ) { serviceUrl = "https://services.arcgis.com/V6ZHFr6zdgNZuVG0/ArcGIS/rest/services/earthquakes_geojson/FeatureServer/0" ; var map = new Map ( { basemap : "topo-vector" } ) ; var view = new MapView ( { container : "viewDiv" , map : map } ) ; // gets a time delta dictionary between two Date objects, 'start' and 'stop' function getTimeDelta ( start , stop ) { var timeDelta = parseInt ( stop - start ) ; var days = parseInt ( timeDelta / 86400000 ) ; var daysRem = timeDelta - ( days * 86400000 ) ; var hours = parseInt ( daysRem / 3600000 ) ; var hoursRem = daysRem - ( hours * 3600000 ) ; var minutes = parseInt ( hoursRem / 60000 ) ; var minutesRem = hoursRem - ( minutes * 60000 ) ; var seconds = parseInt ( minutesRem / 1000 ) ; var milliseconds = minutesRem - ( seconds * 1000 ) ; var results = { days : days , hours : hours , minutes : minutes , seconds : seconds , milliseconds : milliseconds } return results ; } // return Promise (should be total number of records, since OBJECTID should never be blank) function getNumRecords ( ) { var query = new Query ( ) ; query . where = "'OBJECTID' LIKE '%'" ; query . outFields = [ '*' ] ; query . returnGeometry = true ; var queryTask = new QueryTask ( { url : serviceUrl } ) ; return queryTask . executeForCount ( query ) ; } function createQueryFunction ( startId , numRecords ) { return function ( ) { var query = new Query ( ) ; query . start = startId ; query . num = numRecords ; query . outFields = [ '*' ] ; query . returnGeometry = true ; var queryTask = new QueryTask ( { url : serviceUrl } ) ; return queryTask . execute ( query ) } } async function doWork ( promises ) { var results = [ ] ; for ( var promise of promises ) { result = await promise ( ) ; results = results . concat ( result . features ) ; } return results ; } var startTime = new Date ( ) ; getNumRecords ( ) . then ( function ( numRecords ) { console . log ( numRecords ) ; var promises = [ ] ; for ( var i = 0 ; i numRecords ; i + = 1000 ) { promises . push ( createQueryFunction ( i , 1000 ) ) ; } doWork ( promises ) . then ( results = > { console . log ( 'results' , results ) ; var stopTime = new Date ( ) ; console . log ( getTimeDelta ( startTime , stopTime ) ) ; } ) ; } ) ; } ) ; script > head > body > div id = " viewDiv " > div > body > html >

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How to quickly query features from feature service?

VincentLantaca1

Hello. I am trying to figure out a quick way to query features that are on a feature service or map service so that I can go on to create visualizations from them.

Feature services have a limit of how many records you can query at once. This limit is usually 1000. So, as a result I have to keep re-querying until I have all records. So far one way I found to do this is using QueryTask. However it seems quite slow compared to operations dashboard.

Is this a bad approach?

Here is my current method for querying records:

<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>html</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>head</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
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  <SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>meta</SPAN> <SPAN class="attr-name token">charset</SPAN><SPAN class="attr-value token"><SPAN class="punctuation token">=</SPAN><SPAN class="punctuation token">"</SPAN>utf-8<SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN>
  <SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>meta</SPAN> <SPAN class="attr-name token">name</SPAN><SPAN class="attr-value token"><SPAN class="punctuation token">=</SPAN><SPAN class="punctuation token">"</SPAN>viewport<SPAN class="punctuation token">"</SPAN></SPAN> <SPAN class="attr-name token">content</SPAN><SPAN class="attr-value token"><SPAN class="punctuation token">=</SPAN><SPAN class="punctuation token">"</SPAN>initial-scale<SPAN class="punctuation token">=</SPAN>1,maximum-scale<SPAN class="punctuation token">=</SPAN>1,user-scalable<SPAN class="punctuation token">=</SPAN>no<SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN>
  <SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>title</SPAN><SPAN class="punctuation token">></SPAN></SPAN>Query All using QueryTask<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>title</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
  <SPAN class="language-css style token"><SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>style</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
    <SPAN class="selector token">html,
    body,
    #viewDiv</SPAN> <SPAN class="punctuation token">{</SPAN>
      <SPAN class="property token">padding</SPAN><SPAN class="punctuation token">:</SPAN> 0<SPAN class="punctuation token">;</SPAN>
      <SPAN class="property token">margin</SPAN><SPAN class="punctuation token">:</SPAN> 0<SPAN class="punctuation token">;</SPAN>
      <SPAN class="property token">height</SPAN><SPAN class="punctuation token">:</SPAN> 100%<SPAN class="punctuation token">;</SPAN>
      <SPAN class="property token">width</SPAN><SPAN class="punctuation token">:</SPAN> 100%<SPAN class="punctuation token">;</SPAN>
    <SPAN class="punctuation token">}</SPAN>
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  <SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>link</SPAN> <SPAN class="attr-name token">rel</SPAN><SPAN class="attr-value token"><SPAN class="punctuation token">=</SPAN><SPAN class="punctuation token">"</SPAN>stylesheet<SPAN class="punctuation token">"</SPAN></SPAN> <SPAN class="attr-name token">href</SPAN><SPAN class="attr-value token"><SPAN class="punctuation token">=</SPAN><SPAN class="punctuation token">"</SPAN>https://js.arcgis.com/4.11/esri/css/main.css<SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN>
  <SPAN class="language-javascript script token"><SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>script</SPAN> <SPAN class="attr-name token">src</SPAN><SPAN class="attr-value token"><SPAN class="punctuation token">=</SPAN><SPAN class="punctuation token">"</SPAN>https://js.arcgis.com/4.11/<SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN><SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>script</SPAN><SPAN class="punctuation token">></SPAN></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>head</SPAN><SPAN class="punctuation token">></SPAN></SPAN>

<SPAN class="language-javascript script token"><SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>script</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
  <SPAN class="token function">require</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">[</SPAN>
    <SPAN class="string token">"esri/Map"</SPAN><SPAN class="punctuation token">,</SPAN>
    <SPAN class="string token">"esri/views/MapView"</SPAN><SPAN class="punctuation token">,</SPAN>
    <SPAN class="string token">"esri/tasks/support/Query"</SPAN><SPAN class="punctuation token">,</SPAN>
    <SPAN class="string token">"esri/tasks/QueryTask"</SPAN><SPAN class="punctuation token">,</SPAN>
    <SPAN class="string token">"esri/Graphic"</SPAN><SPAN class="punctuation token">,</SPAN>
    <SPAN class="string token">"dojo/domReady!"</SPAN>
  <SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">,</SPAN>
  <SPAN class="keyword token">function</SPAN><SPAN class="punctuation token">(</SPAN>
    Map<SPAN class="punctuation token">,</SPAN> 
    MapView<SPAN class="punctuation token">,</SPAN>
    Query<SPAN class="punctuation token">,</SPAN>
    QueryTask<SPAN class="punctuation token">,</SPAN>
    Graphic
  <SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">{</SPAN>
    serviceUrl <SPAN class="operator token">=</SPAN> <SPAN class="string token">"https://services.arcgis.com/V6ZHFr6zdgNZuVG0/ArcGIS/rest/services/earthquakes_geojson/FeatureServer/0"</SPAN><SPAN class="punctuation token">;</SPAN>

    <SPAN class="keyword token">var</SPAN> map <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">Map</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">{</SPAN>
      basemap<SPAN class="punctuation token">:</SPAN> <SPAN class="string token">"topo-vector"</SPAN>
    <SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>

    <SPAN class="keyword token">var</SPAN> view <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">MapView</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">{</SPAN>
      container<SPAN class="punctuation token">:</SPAN> <SPAN class="string token">"viewDiv"</SPAN><SPAN class="punctuation token">,</SPAN>
      map<SPAN class="punctuation token">:</SPAN> map
    <SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>

    <SPAN class="comment token">// gets a time delta dictionary between two Date objects, 'start' and 'stop'</SPAN>
    <SPAN class="keyword token">function</SPAN> <SPAN class="token function">getTimeDelta</SPAN><SPAN class="punctuation token">(</SPAN>start<SPAN class="punctuation token">,</SPAN> stop<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">{</SPAN>
      <SPAN class="keyword token">var</SPAN> timeDelta <SPAN class="operator token">=</SPAN> <SPAN class="token function">parseInt</SPAN><SPAN class="punctuation token">(</SPAN>stop <SPAN class="operator token">-</SPAN> start<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
      <SPAN class="keyword token">var</SPAN> days <SPAN class="operator token">=</SPAN> <SPAN class="token function">parseInt</SPAN><SPAN class="punctuation token">(</SPAN>timeDelta <SPAN class="operator token">/</SPAN> <SPAN class="number token">86400000</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
      <SPAN class="keyword token">var</SPAN> daysRem <SPAN class="operator token">=</SPAN> timeDelta <SPAN class="operator token">-</SPAN> <SPAN class="punctuation token">(</SPAN>days <SPAN class="operator token">*</SPAN> <SPAN class="number token">86400000</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
      <SPAN class="keyword token">var</SPAN> hours <SPAN class="operator token">=</SPAN> <SPAN class="token function">parseInt</SPAN><SPAN class="punctuation token">(</SPAN>daysRem <SPAN class="operator token">/</SPAN> <SPAN class="number token">3600000</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
      <SPAN class="keyword token">var</SPAN> hoursRem <SPAN class="operator token">=</SPAN> daysRem <SPAN class="operator token">-</SPAN> <SPAN class="punctuation token">(</SPAN>hours <SPAN class="operator token">*</SPAN> <SPAN class="number token">3600000</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
      <SPAN class="keyword token">var</SPAN> minutes <SPAN class="operator token">=</SPAN> <SPAN class="token function">parseInt</SPAN><SPAN class="punctuation token">(</SPAN>hoursRem <SPAN class="operator token">/</SPAN> <SPAN class="number token">60000</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
      <SPAN class="keyword token">var</SPAN> minutesRem <SPAN class="operator token">=</SPAN> hoursRem <SPAN class="operator token">-</SPAN> <SPAN class="punctuation token">(</SPAN>minutes <SPAN class="operator token">*</SPAN> <SPAN class="number token">60000</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
      <SPAN class="keyword token">var</SPAN> seconds <SPAN class="operator token">=</SPAN> <SPAN class="token function">parseInt</SPAN><SPAN class="punctuation token">(</SPAN>minutesRem <SPAN class="operator token">/</SPAN> <SPAN class="number token">1000</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
      <SPAN class="keyword token">var</SPAN> milliseconds <SPAN class="operator token">=</SPAN> minutesRem <SPAN class="operator token">-</SPAN> <SPAN class="punctuation token">(</SPAN>seconds <SPAN class="operator token">*</SPAN> <SPAN class="number token">1000</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>

      <SPAN class="keyword token">var</SPAN> results <SPAN class="operator token">=</SPAN> <SPAN class="punctuation token">{</SPAN>
        days<SPAN class="punctuation token">:</SPAN> days<SPAN class="punctuation token">,</SPAN>
        hours<SPAN class="punctuation token">:</SPAN> hours<SPAN class="punctuation token">,</SPAN>
        minutes<SPAN class="punctuation token">:</SPAN> minutes<SPAN class="punctuation token">,</SPAN>
        seconds<SPAN class="punctuation token">:</SPAN> seconds<SPAN class="punctuation token">,</SPAN>
        milliseconds<SPAN class="punctuation token">:</SPAN> milliseconds
      <SPAN class="punctuation token">}</SPAN>

      <SPAN class="keyword token">return</SPAN> results<SPAN class="punctuation token">;</SPAN>
    <SPAN class="punctuation token">}</SPAN>

    <SPAN class="comment token">// return Promise<Number> (should be total number of records, since OBJECTID should never be blank)</SPAN>
    <SPAN class="keyword token">function</SPAN> <SPAN class="token function">getNumRecords</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">{</SPAN>
      <SPAN class="keyword token">var</SPAN> query <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">Query</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
      query<SPAN class="punctuation token">.</SPAN>where <SPAN class="operator token">=</SPAN> <SPAN class="string token">"'OBJECTID' LIKE '%'"</SPAN><SPAN class="punctuation token">;</SPAN>
      query<SPAN class="punctuation token">.</SPAN>outFields <SPAN class="operator token">=</SPAN> <SPAN class="punctuation token">[</SPAN><SPAN class="string token">'*'</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">;</SPAN>
      query<SPAN class="punctuation token">.</SPAN>returnGeometry <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">true</SPAN><SPAN class="punctuation token">;</SPAN>
      <SPAN class="keyword token">var</SPAN> queryTask <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">QueryTask</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">{</SPAN>
        url<SPAN class="punctuation token">:</SPAN> serviceUrl
      <SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>

      <SPAN class="keyword token">return</SPAN> queryTask<SPAN class="punctuation token">.</SPAN><SPAN class="token function">executeForCount</SPAN><SPAN class="punctuation token">(</SPAN>query<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
    <SPAN class="punctuation token">}</SPAN>

    <SPAN class="keyword token">function</SPAN> <SPAN class="token function">createQueryFunction</SPAN><SPAN class="punctuation token">(</SPAN>startId<SPAN class="punctuation token">,</SPAN> numRecords<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">{</SPAN>
      <SPAN class="keyword token">return</SPAN> <SPAN class="keyword token">function</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">{</SPAN>
        <SPAN class="keyword token">var</SPAN> query <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">Query</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
        query<SPAN class="punctuation token">.</SPAN>start <SPAN class="operator token">=</SPAN> startId<SPAN class="punctuation token">;</SPAN>
        query<SPAN class="punctuation token">.</SPAN>num <SPAN class="operator token">=</SPAN> numRecords<SPAN class="punctuation token">;</SPAN>
        query<SPAN class="punctuation token">.</SPAN>outFields <SPAN class="operator token">=</SPAN> <SPAN class="punctuation token">[</SPAN><SPAN class="string token">'*'</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">;</SPAN>
        query<SPAN class="punctuation token">.</SPAN>returnGeometry <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">true</SPAN><SPAN class="punctuation token">;</SPAN>
        <SPAN class="keyword token">var</SPAN> queryTask <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">QueryTask</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">{</SPAN>
          url<SPAN class="punctuation token">:</SPAN> serviceUrl
        <SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>

        <SPAN class="keyword token">return</SPAN> queryTask<SPAN class="punctuation token">.</SPAN><SPAN class="token function">execute</SPAN><SPAN class="punctuation token">(</SPAN>query<SPAN class="punctuation token">)</SPAN>
      <SPAN class="punctuation token">}</SPAN>
    <SPAN class="punctuation token">}</SPAN>

    <SPAN class="keyword token">async</SPAN> <SPAN class="keyword token">function</SPAN> <SPAN class="token function">doWork</SPAN><SPAN class="punctuation token">(</SPAN>promises<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">{</SPAN>
      <SPAN class="keyword token">var</SPAN> results <SPAN class="operator token">=</SPAN> <SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">;</SPAN>

      <SPAN class="keyword token">for</SPAN> <SPAN class="punctuation token">(</SPAN><SPAN class="keyword token">var</SPAN> promise <SPAN class="keyword token">of</SPAN> promises<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">{</SPAN>
        result <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">await</SPAN> <SPAN class="token function">promise</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
        results <SPAN class="operator token">=</SPAN> results<SPAN class="punctuation token">.</SPAN><SPAN class="token function">concat</SPAN><SPAN class="punctuation token">(</SPAN>result<SPAN class="punctuation token">.</SPAN>features<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
      <SPAN class="punctuation token">}</SPAN>

      <SPAN class="keyword token">return</SPAN> results<SPAN class="punctuation token">;</SPAN>
    <SPAN class="punctuation token">}</SPAN>

    <SPAN class="keyword token">var</SPAN> startTime <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">Date</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>

    <SPAN class="token function">getNumRecords</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="token function">then</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="keyword token">function</SPAN><SPAN class="punctuation token">(</SPAN>numRecords<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">{</SPAN>
      console<SPAN class="punctuation token">.</SPAN><SPAN class="token function">log</SPAN><SPAN class="punctuation token">(</SPAN>numRecords<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>

      <SPAN class="keyword token">var</SPAN> promises <SPAN class="operator token">=</SPAN> <SPAN class="punctuation token">[</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="punctuation token">;</SPAN>
      <SPAN class="keyword token">for</SPAN> <SPAN class="punctuation token">(</SPAN><SPAN class="keyword token">var</SPAN> i<SPAN class="operator token">=</SPAN><SPAN class="number token">0</SPAN><SPAN class="punctuation token">;</SPAN> i<SPAN class="operator token"><</SPAN>numRecords<SPAN class="punctuation token">;</SPAN> i <SPAN class="operator token">+</SPAN><SPAN class="operator token">=</SPAN> <SPAN class="number token">1000</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">{</SPAN>
        promises<SPAN class="punctuation token">.</SPAN><SPAN class="token function">push</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="token function">createQueryFunction</SPAN><SPAN class="punctuation token">(</SPAN>i<SPAN class="punctuation token">,</SPAN> <SPAN class="number token">1000</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
      <SPAN class="punctuation token">}</SPAN>

      <SPAN class="token function">doWork</SPAN><SPAN class="punctuation token">(</SPAN>promises<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="token function">then</SPAN><SPAN class="punctuation token">(</SPAN>results <SPAN class="operator token">=</SPAN><SPAN class="operator token">></SPAN> <SPAN class="punctuation token">{</SPAN>
        console<SPAN class="punctuation token">.</SPAN><SPAN class="token function">log</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">'results'</SPAN><SPAN class="punctuation token">,</SPAN> results<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
        <SPAN class="keyword token">var</SPAN> stopTime <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">Date</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
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Accepted answers

JackFairfield

Hey Vincent,

Have you looked into ESRI's Rest JS library? It is useful when you don't necessarily need to show a map.

You could do something like this to fetch all of the features quickly:

https://jsbin.com/sehunejone/edit?html,output

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width">
    <title>ArcGIS REST JS - AMD</title>
</head>

<body>
    Open your console to see the demo.
</body>
<script src="https://unpkg.com/@esri/arcgis-rest-request@2.0.3/dist/umd/request.umd.js"></script>
<script src="https://unpkg.com/@esri/arcgis-rest-feature-layer@2.0.3/dist/umd/feature-layer.umd.js"></script>
<script>
    var url = "https://services.arcgis.com/V6ZHFr6zdgNZuVG0/ArcGIS/rest/services/earthquakes_geojson/FeatureServer/0";

    async function GetRecordCount() {
        var { count } = await arcgisRest.queryFeatures({
            url: url,
            returnCountOnly: true
        });
        return count;
    }

    async function GetData() {

        let numRecords = await GetRecordCount();
        let promises = [];
        let data = [];
        const maxRecordCount = 1000;

        for (var i = 0; i < numRecords; i += maxRecordCount) {
            let q = arcgisRest.queryFeatures({
                url: url,
                resultOffset: i,
                resultRecordCount: maxRecordCount
            });
            promises.push(q);
        }

        let dataArr = await Promise.all(promises);
        for (const res of dataArr) {
            data = data.concat(res.features);
        }
        return data;
    }
    var t0 = performance.now();
    GetData().then(function(res) {
        var t1 = performance.now();
        console.log("Query took " + Math.floor(t1 - t0) + " milliseconds.");
        console.log(res);
    })
</script>

</html>

All comments

VincentLantaca1

This is great, I had no idea this existed!

JackFairfield

Hey Vincent,

Have you looked into ESRI's Rest JS library? It is useful when you don't necessarily need to show a map.

You could do something like this to fetch all of the features quickly:

https://jsbin.com/sehunejone/edit?html,output

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width">
    <title>ArcGIS REST JS - AMD</title>
</head>

<body>
    Open your console to see the demo.
</body>
<script src="https://unpkg.com/@esri/arcgis-rest-request@2.0.3/dist/umd/request.umd.js"></script>
<script src="https://unpkg.com/@esri/arcgis-rest-feature-layer@2.0.3/dist/umd/feature-layer.umd.js"></script>
<script>
    var url = "https://services.arcgis.com/V6ZHFr6zdgNZuVG0/ArcGIS/rest/services/earthquakes_geojson/FeatureServer/0";

    async function GetRecordCount() {
        var { count } = await arcgisRest.queryFeatures({
            url: url,
            returnCountOnly: true
        });
        return count;
    }

    async function GetData() {

        let numRecords = await GetRecordCount();
        let promises = [];
        let data = [];
        const maxRecordCount = 1000;

        for (var i = 0; i < numRecords; i += maxRecordCount) {
            let q = arcgisRest.queryFeatures({
                url: url,
                resultOffset: i,
                resultRecordCount: maxRecordCount
            });
            promises.push(q);
        }

        let dataArr = await Promise.all(promises);
        for (const res of dataArr) {
            data = data.concat(res.features);
        }
        return data;
    }
    var t0 = performance.now();
    GetData().then(function(res) {
        var t1 = performance.now();
        console.log("Query took " + Math.floor(t1 - t0) + " milliseconds.");
        console.log(res);
    })
</script>

</html>

VincentLantaca1

Thanks. One reason I didn't do this was that I was worried about CPU usage. However this seems to work fine. Oddly enough, operations dashboards seem to create visualizations based on all records yet they load fast and don't use up as much CPU. I'm wondering if there are other approaches to querying records with ArcGIS JS.

JackFairfield

One thing you can do to slightly improve performance is to make sure all of your requests aren't waiting for the previous query to finish before they run. You can change the doWork function to something like this:

async function doWork(promiseFunctions) {
    var promises = [];
    for (var func of promiseFunctions) {
        promises.push(func());
    }
    var results = [];
    for (var result of await Promise.all(promises)) {
        results = results.concat(result.features);
    }
    return results;
}

This way, you are awaiting all of the promises at once instead of doing them in order and having to await each one.

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