add shardKeyAttribute to pregel start parameters (#9149)

CHANGELOG

@@ -1,6 +1,8 @@
 devel
 -----
 
+* allow pregel to select the shard key via `shardKeyAttribute` in pregel start parameters
+
 * Added --server.jwt-secret-keyfile to arangosh.
 
 * fixed `Buffer.alloc` method

arangod/Pregel/Conductor.cpp

@@ -112,6 +112,11 @@ void Conductor::start() {
   MUTEX_LOCKER(guard, _callbackMutex);
   _callbackMutex.assertLockedByCurrentThread();
   _startTimeSecs = TRI_microtime();
+
+  _computationStartTimeSecs = _startTimeSecs;
+  _finalizationStartTimeSecs = _startTimeSecs;
+  _endTimeSecs = _startTimeSecs;
+
   _globalSuperstep = 0;
   _state = ExecutionState::RUNNING;
 

arangod/Pregel/Iterators.h

@@ -101,7 +101,7 @@ class RangeIterator {
     : _buffers(bufs),
       _beginBuffer(beginBuffer),
       _beginPtr(beginPtr),
-      _currentBufferEnd(bufs[_beginBuffer]->end()),
+      _currentBufferEnd(bufs.empty() ? beginPtr : bufs[_beginBuffer]->end()),
       _size(size) {}
 
   RangeIterator(RangeIterator const&) = delete;

arangod/Pregel/PregelFeature.cpp

@@ -83,6 +83,7 @@ std::pair<Result, uint64_t> PregelFeature::startExecution(
     std::vector<std::string> const& vertexCollections,
     std::vector<std::string> const& edgeCollections, VPackSlice const& params) {
 
+
   // make sure no one removes the PregelFeature while in use
   std::shared_ptr<PregelFeature> instance = ::instance;
 
@@ -162,10 +163,21 @@ std::pair<Result, uint64_t> PregelFeature::startExecution(
 
         if (!coll->isSmart()) {
           std::vector<std::string> eKeys = coll->shardKeys();
-          if (eKeys.size() != 1 || eKeys[0] != "vertex") {
+
+          std::string shardKeyAttribute = "vertex";
+          if(params.hasKey("shardKeyAttribute")) {
+           shardKeyAttribute =  params.get("shardKeyAttribute").copyString();
+          }
+
+          if (eKeys.size() != 1 || eKeys[0] != shardKeyAttribute) {
             return std::make_pair(Result{TRI_ERROR_BAD_PARAMETER,
                                          "Edge collection needs to be sharded "
-                                         "after 'vertex', or use smart graphs"},
+                                         "after shardKeyAttribute parameter ('"
+                                         + shardKeyAttribute
+                                         + "'), or use smart graphs. The current shardKey is: "
+                                         + (eKeys.empty() ? "undefined" : "'" + eKeys[0] + "'")
+
+                                         },
                                   0);
           }
         }

tests/js/common/shell/shell-pregel-start-cluster.js

@@ -0,0 +1,319 @@
+/*jshint globalstrict:false, strict:false */
+/*global assertEqual, assertNotEqual, assertTrue JSON */
+'use strict';
+
+// //////////////////////////////////////////////////////////////////////////////
+// / @brief Pregel Tests
+// /
+// / @file
+// /
+// / DISCLAIMER
+// /
+// / Copyright 2017 ArangoDB GmbH, Cologne, Germany
+// /
+// / Licensed under the Apache License, Version 2.0 (the "License")
+// / you may not use this file except in compliance with the License.
+// / You may obtain a copy of the License at
+// /
+// /     http://www.apache.org/licenses/LICENSE-2.0
+// /
+// / Unless required by applicable law or agreed to in writing, software
+// / distributed under the License is distributed on an "AS IS" BASIS,
+// / WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// / See the License for the specific language governing permissions and
+// / limitations under the License.
+// /
+// / Copyright holder is ArangoDB GmbH, Cologne, Germany
+// /
+// / @author Jan Christoph Uhde
+// / @author Copyright 2019, ArangoDB GmbH, Cologne, Germany
+// //////////////////////////////////////////////////////////////////////////////
+
+var jsunity = require("jsunity");
+var db = require("@arangodb").db;
+var internal = require("internal");
+let pregel = require("@arangodb/pregel");
+var graph_module = require("@arangodb/general-graph");
+
+var EPS = 0.0001;
+
+const graphName = "UnitTest_pregel";
+const vColl = "UnitTest_pregel_v", eColl = "UnitTest_pregel_e";
+
+function shardKeysTestSuite() {
+  'use strict';
+  var pid;
+  return {
+
+    ////////////////////////////////////////////////////////////////////////////////
+    /// @brief set up
+    ////////////////////////////////////////////////////////////////////////////////
+
+    setUp: function () {
+      pid = 0;
+      db._create(vColl, { numberOfShards : 3 } );
+    },
+
+    ////////////////////////////////////////////////////////////////////////////////
+    /// @brief tear down
+    ////////////////////////////////////////////////////////////////////////////////
+
+    tearDown: function () {
+
+      if(pid !== 0) {
+        while(pregel.status(pid).state === 'running') {
+          internal.sleep(0.1);
+        }
+        pregel.cancel(pid); // delete contents
+      }
+
+      internal.wait(5.0);
+
+      db._drop(eColl);
+      db._drop(vColl);
+    },
+
+    testStartPregelShardKeyVertex: function () {
+      db._createEdgeCollection(eColl, { distributeShardsLike: vColl , shardKeys : [ "vertex" ] } );
+
+      pid = pregel.start("pagerank", {
+        vertexCollections:[vColl],
+        edgeCollections:[eColl]
+      }, {
+        threshold: 0.0000000001,
+        resultField: "result",
+        store: false,
+        useMemoryMaps: true,
+      });
+
+      assertNotEqual(0,pid);
+    },
+
+    testStartPregelShardKeyUndefined: function () {
+      db._createEdgeCollection(eColl, { distributeShardsLike: vColl } );
+
+      pid = pregel.start("pagerank", {
+        vertexCollections:[vColl],
+        edgeCollections:[eColl]
+      }, {
+        threshold: 0.0000000001,
+        resultField: "result",
+        store: false,
+        useMemoryMaps: true,
+        shardKeyAttribute: "_key"
+      });
+      assertNotEqual(0,pid);
+    },
+
+    testStartPregelShardKeyCustom: function () {
+      db._createEdgeCollection(eColl, { distributeShardsLike: vColl , shardKeys : [ "ulf" ] } );
+
+      pid = pregel.start("pagerank", {
+        vertexCollections:[vColl],
+        edgeCollections:[eColl]
+      }, {
+        threshold: 0.0000000001,
+        resultField: "result",
+        store: false,
+        useMemoryMaps: true,
+        shardKeyAttribute: "ulf"
+      });
+      assertNotEqual(0,pid);
+
+    },
+
+  }; //return
+}; //basic
+
+
+
+function basicTestSuite() {
+  'use strict';
+  const shardKey = "ulf";
+
+  function testAlgo(a, p) {
+    p.shardKeyAttribute = shardKey;
+    var pid = pregel.start(a, graphName, p);
+    var i = 10000;
+    do {
+      internal.wait(0.2);
+      var stats = pregel.status(pid);
+      if (stats.state !== "running") {
+        assertEqual(stats.vertexCount, 11, stats);
+        assertEqual(stats.edgeCount, 17, stats);
+  
+        db[vColl].all().toArray()
+          .forEach(function (d) {
+            if (d[a] && d[a] !== -1) {
+              var diff = Math.abs(d[a] - d.result);
+              if (diff > EPS) {
+                console.log("Error on " + JSON.stringify(d));
+                assertTrue(false);// peng
+              }
+            }
+          });
+        break;
+      }
+    } while (i-- >= 0);
+    if (i === 0) {
+      assertTrue(false, "timeout in pregel execution");
+    }
+  }
+
+  return {
+
+   ////////////////////////////////////////////////////////////////////////////////
+    /// @brief set up
+    ////////////////////////////////////////////////////////////////////////////////
+
+    setUp: function () {
+
+      var exists = graph_module._list().indexOf("demo") !== -1;
+      if (exists || db.demo_v) {
+        return;
+      }
+      var graph = graph_module._create(graphName);
+      db._create(vColl, { numberOfShards: 4 });
+      graph._addVertexCollection(vColl);
+      db._createEdgeCollection(eColl, {
+        numberOfShards: 4,
+        replicationFactor: 1,
+        shardKeys: [ shardKey ],
+        distributeShardsLike: vColl
+      });
+
+      var rel = graph_module._relation(eColl, [vColl], [vColl]);
+      graph._extendEdgeDefinitions(rel);
+
+      var vertices = db[vColl];
+      var edges = db[eColl];
+
+
+      var A = vertices.insert({ _key: 'A', sssp: 3, pagerank: 0.027645934 })._id;
+      var B = vertices.insert({ _key: 'B', sssp: 2, pagerank: 0.3241496 })._id;
+      var C = vertices.insert({ _key: 'C', sssp: 3, pagerank: 0.289220 })._id;
+      var D = vertices.insert({ _key: 'D', sssp: 2, pagerank: 0.0329636 })._id;
+      var E = vertices.insert({ _key: 'E', sssp: 1, pagerank: 0.0682141 })._id;
+      var F = vertices.insert({ _key: 'F', sssp: 2, pagerank: 0.0329636 })._id;
+      var G = vertices.insert({ _key: 'G', sssp: -1, pagerank: 0.0136363 })._id;
+      var H = vertices.insert({ _key: 'H', sssp: -1, pagerank: 0.01363636 })._id;
+      var I = vertices.insert({ _key: 'I', sssp: -1, pagerank: 0.01363636 })._id;
+      var J = vertices.insert({ _key: 'J', sssp: -1, pagerank: 0.01363636 })._id;
+      var K = vertices.insert({ _key: 'K', sssp: 0, pagerank: 0.013636363 })._id;
+
+      edges.insert({ _from: B, _to: C, [shardKey]: 'B' });
+      edges.insert({ _from: C, _to: B, [shardKey]: 'C' });
+      edges.insert({ _from: D, _to: A, [shardKey]: 'D' });
+      edges.insert({ _from: D, _to: B, [shardKey]: 'D' });
+      edges.insert({ _from: E, _to: B, [shardKey]: 'E' });
+      edges.insert({ _from: E, _to: D, [shardKey]: 'E' });
+      edges.insert({ _from: E, _to: F, [shardKey]: 'E' });
+      edges.insert({ _from: F, _to: B, [shardKey]: 'F' });
+      edges.insert({ _from: F, _to: E, [shardKey]: 'F' });
+      edges.insert({ _from: G, _to: B, [shardKey]: 'G' });
+      edges.insert({ _from: G, _to: E, [shardKey]: 'G' });
+      edges.insert({ _from: H, _to: B, [shardKey]: 'H' });
+      edges.insert({ _from: H, _to: E, [shardKey]: 'H' });
+      edges.insert({ _from: I, _to: B, [shardKey]: 'I' });
+      edges.insert({ _from: I, _to: E, [shardKey]: 'I' });
+      edges.insert({ _from: J, _to: E, [shardKey]: 'J' });
+      edges.insert({ _from: K, _to: E, [shardKey]: 'K' });
+    },
+
+    ////////////////////////////////////////////////////////////////////////////////
+    /// @brief tear down
+    ////////////////////////////////////////////////////////////////////////////////
+
+    tearDown: function () {
+      graph_module._drop(graphName, true);
+    },
+
+    testSSSPNormal: function () {
+      testAlgo("sssp", { async: false, source: vColl + "/K", resultField: "result", store: true });
+    },
+
+    testSSSPAsync: function () {
+      testAlgo("sssp", { async: true, source: vColl + "/K", resultField: "result", store: true });
+    },
+
+    testPageRank: function () {
+      // should test correct convergence behaviour, might fail if EPS is too low
+      testAlgo("pagerank", { threshold: EPS / 10, resultField: "result", store: true });
+    },
+
+    testPageRankMMap: function () {
+      // should test correct convergence behaviour, might fail if EPS is too low
+      testAlgo("pagerank", { threshold: EPS / 10, resultField: "result", store: true, useMemoryMaps: true });
+    },
+
+    testPageRankSeeded: function () {
+      // test that pagerank picks the seed value
+      testAlgo("pagerank", { maxGSS: 1, sourceField: "pagerank", resultField: "result", store: true });
+      // since we already use converged values this should not change anything
+      testAlgo("pagerank", { maxGSS: 5, sourceField: "pagerank", resultField: "result", store: true });
+    },
+
+    // test the PREGEL_RESULT AQL function
+    testPageRankAQLResult: function () {
+      var pid = pregel.start("pagerank", graphName, { shardKeyAttribute: shardKey, threshold: EPS / 10, store: false });
+      var i = 10000;
+      do {
+        internal.wait(0.2);
+        var stats = pregel.status(pid);
+        if (stats.state !== "running") {
+          assertEqual(stats.vertexCount, 11, stats);
+          assertEqual(stats.edgeCount, 17, stats);
+
+          let vertices = db._collection(vColl);
+          // no result was written to the default result field
+          vertices.all().toArray().forEach(d => assertTrue(!d.result));
+
+          let array = db._query("RETURN PREGEL_RESULT(@id)", { "id": pid }).toArray();
+          assertEqual(array.length, 1);
+          let results = array[0];
+          assertEqual(results.length, 11);
+
+          // verify results
+          results.forEach(function (d) {
+            let v = vertices.document(d._key);
+            assertTrue(v !== null);
+            assertTrue(Math.abs(v.pagerank - d.result) < EPS);
+          });
+
+          array = db._query("RETURN PREGEL_RESULT(@id, true)", { "id": pid }).toArray();
+          assertEqual(array.length, 1);
+          results = array[0];
+          assertEqual(results.length, 11);
+
+          // verify results
+          results.forEach(function (d) {
+            let v = vertices.document(d._key);
+            assertTrue(v !== null);
+            assertTrue(Math.abs(v.pagerank - d.result) < EPS);
+
+            let v2 = db._document(d._id);
+            assertEqual(v, v2);
+          });
+
+          pregel.cancel(pid); // delete contents
+          internal.wait(5.0);
+
+          array = db._query("RETURN PREGEL_RESULT(@id)", { "id": pid }).toArray();
+          assertEqual(array.length, 1);
+          results = array[0];
+          assertEqual(results.length, 0);
+
+          break;
+        }
+      } while (i-- >= 0);
+      if (i === 0) {
+        assertTrue(false, "timeout in pregel execution");
+      }
+    }
+  };
+};
+
+jsunity.run(shardKeysTestSuite);
+jsunity.run(basicTestSuite);
+
+return jsunity.done();