fix(interactive): Remove Unnecessary JNA Structure Creation to Save M…

…emory Consumption (#3354)

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## What do these changes do?
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Fixes

interactive_engine/compiler/src/main/java/com/alibaba/graphscope/common/intermediate/ArgVariable.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2020 Alibaba Group Holding Limited.
+ *
+ * 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.
+ */
+
+package com.alibaba.graphscope.common.intermediate;
+
+public class ArgVariable {
+    private final String tagName;
+    private final String propertyName;
+
+    public ArgVariable(String tagName, String propertyName) {
+        this.tagName = tagName;
+        this.propertyName = propertyName;
+    }
+
+    @Override
+    public String toString() {
+        return (propertyName == null || propertyName.isEmpty())
+                ? "@" + tagName
+                : "@" + tagName + "." + propertyName;
+    }
+}

interactive_engine/compiler/src/main/java/com/alibaba/graphscope/gremlin/transform/PredicateExprTransformFactory.java

@@ -16,7 +16,7 @@
 
 package com.alibaba.graphscope.gremlin.transform;
 
-import com.alibaba.graphscope.common.intermediate.ArgUtils;
+import com.alibaba.graphscope.common.intermediate.ArgVariable;
 
 import org.apache.tinkerpop.gremlin.process.traversal.P;
 import org.apache.tinkerpop.gremlin.process.traversal.Step;
@@ -64,7 +64,7 @@ public String apply(Step arg) {
         public String apply(Step arg) {
             WhereTraversalStep.WhereEndStep endStep = (WhereTraversalStep.WhereEndStep) arg;
             String matchTag = endStep.getScopeKeys().iterator().next();
-            P predicate = P.eq(ArgUtils.asVar(matchTag, ""));
+            P predicate = P.eq(new ArgVariable(matchTag, ""));
             return flatPredicate("@", predicate);
         }
     }

interactive_engine/compiler/src/main/java/com/alibaba/graphscope/gremlin/transform/StepTransformFactory.java

@@ -401,17 +401,13 @@ public InterOpBase apply(Step step) {
         private String getMapKey(TraversalMapStep step) {
             Step groupStep = getPreviousGroupStep(step);
             int stepIdx = TraversalHelper.stepIndex(groupStep, groupStep.getTraversal());
-            FfiAlias.ByValue keyAlias =
-                    AliasManager.getFfiAlias(new AliasArg(AliasPrefixType.GROUP_KEYS, stepIdx));
-            return keyAlias.alias.name;
+            return AliasManager.getAliasName(new AliasArg(AliasPrefixType.GROUP_KEYS, stepIdx));
         }
 
         private String getMapValue(TraversalMapStep step) {
             Step groupStep = getPreviousGroupStep(step);
             int stepIdx = TraversalHelper.stepIndex(groupStep, groupStep.getTraversal());
-            FfiAlias.ByValue valueAlias =
-                    AliasManager.getFfiAlias(new AliasArg(AliasPrefixType.GROUP_VALUES, stepIdx));
-            return valueAlias.alias.name;
+            return AliasManager.getAliasName(new AliasArg(AliasPrefixType.GROUP_VALUES, stepIdx));
         }
 
         private Step getPreviousGroupStep(Step step) {

interactive_engine/compiler/src/main/java/com/alibaba/graphscope/gremlin/transform/TraversalParentTransform.java

@@ -19,6 +19,7 @@
 import com.alibaba.graphscope.common.exception.OpArgIllegalException;
 import com.alibaba.graphscope.common.intermediate.ArgAggFn;
 import com.alibaba.graphscope.common.intermediate.ArgUtils;
+import com.alibaba.graphscope.common.intermediate.ArgVariable;
 import com.alibaba.graphscope.common.intermediate.operator.InterOpBase;
 import com.alibaba.graphscope.common.intermediate.operator.ProjectOp;
 import com.alibaba.graphscope.common.jna.type.FfiAggOpt;
@@ -245,6 +246,22 @@ default FfiVariable.ByValue getExpressionAsVar(String expr) {
         return ArgUtils.asVar(tag, property);
     }
 
+    default ArgVariable getExpressionAsArgVar(String expr) {
+        if (expr.startsWith("{") && expr.endsWith("}")) {
+            throw new OpArgIllegalException(
+                    OpArgIllegalException.Cause.INVALID_TYPE,
+                    "can not convert expression of valueMap to variable");
+        }
+        String[] splitExpr = expr.split("\\.");
+        if (splitExpr.length == 0) {
+            throw new OpArgIllegalException(
+                    OpArgIllegalException.Cause.INVALID_TYPE, "expr " + expr + " is invalid");
+        }
+        String tag = (splitExpr[0].length() > 0) ? splitExpr[0].substring(1) : splitExpr[0];
+        String property = (splitExpr.length > 1) ? splitExpr[1] : "";
+        return new ArgVariable(tag, property);
+    }
+
     default Map<String, Traversal.Admin> getProjectTraversals(TraversalParent parent) {
         if (parent instanceof SelectOneStep) {
             SelectOneStep step = (SelectOneStep) parent;
@@ -272,9 +289,6 @@ default Map<String, Traversal.Admin> getProjectTraversals(TraversalParent parent
     // AliasManager in an automatic way or is given by the query)
     // and get aggregate variable, set to NONE by default
     default ArgAggFn getAggFn(Step step, int stepIdx, int subId) {
-        FfiAlias.ByValue alias =
-                AliasManager.getFfiAlias(
-                        new AliasArg(AliasPrefixType.GROUP_VALUES, stepIdx, subId));
         FfiAggOpt aggOpt;
         if (step instanceof CountGlobalStep) {
             aggOpt = FfiAggOpt.Count;
@@ -293,11 +307,16 @@ default ArgAggFn getAggFn(Step step, int stepIdx, int subId) {
                     OpArgIllegalException.Cause.UNSUPPORTED_TYPE,
                     "invalid aggFn " + step.getClass());
         }
+        FfiAlias.ByValue alias;
         // group().by(..).by(count().as("a")), "a" is the query given alias of group value
         Set<String> labels = step.getLabels();
         if (labels != null && !labels.isEmpty()) {
             String label = labels.iterator().next();
             alias = ArgUtils.asAlias(label, true);
+        } else {
+            alias =
+                    AliasManager.getFfiAlias(
+                            new AliasArg(AliasPrefixType.GROUP_VALUES, stepIdx, subId));
         }
         // set to NONE by default
         return new ArgAggFn(aggOpt, alias);

interactive_engine/compiler/src/main/java/com/alibaba/graphscope/gremlin/transform/TraversalParentTransformFactory.java

@@ -19,6 +19,7 @@
 import com.alibaba.graphscope.common.exception.OpArgIllegalException;
 import com.alibaba.graphscope.common.intermediate.ArgAggFn;
 import com.alibaba.graphscope.common.intermediate.ArgUtils;
+import com.alibaba.graphscope.common.intermediate.ArgVariable;
 import com.alibaba.graphscope.common.intermediate.operator.*;
 import com.alibaba.graphscope.common.jna.type.*;
 import com.alibaba.graphscope.gremlin.InterOpCollectionBuilder;
@@ -495,7 +496,7 @@ private void traverseAndUpdateP(
                                 stepId,
                                 subId,
                                 applys);
-                FfiVariable.ByValue var = getExpressionAsVar(expr);
+                ArgVariable var = getExpressionAsArgVar(expr);
                 predicate.setValue(var);
             }
         }

interactive_engine/compiler/src/main/java/com/alibaba/graphscope/gremlin/transform/alias/AliasManager.java

@@ -27,6 +27,12 @@ public static FfiAlias.ByValue getFfiAlias(AliasArg prefix) {
         return ArgUtils.asAlias(alias, false);
     }
 
+    public static String getAliasName(AliasArg prefix) {
+        int stepIdx = prefix.getStepIdx();
+        int subTraversalId = prefix.getSubTraversalIdx();
+        return prefix.getPrefix() + "_" + stepIdx + "_" + subTraversalId;
+    }
+
     // prefix is as the gremlin result key which is used to display
     public static String getPrefix(String aliasName) {
         String[] splits = aliasName.split("_");