Max Query Size

Summary: Query Size Limit in Python, Java, JavaScript

Reviewers: mferencevic, mislav.bradac, teon.banek

Reviewed By: mferencevic, teon.banek

Subscribers: pullbot, buda

Differential Revision: https://phabricator.memgraph.io/D508

docs/user_technical/quick-start.md

@@ -224,7 +224,7 @@ to remove in future versions.
 
 The maximum length of a query that can be sent from a driver in Python is
 `16378` characters, from a driver in Java `8184` and from a driver in
-JavaScript `1373` characters.
+JavaScript `1392` characters.
 
 #### Multiple-Query Transactions
 

tests/drivers/java/Basic.java

@@ -3,7 +3,7 @@ import org.neo4j.driver.v1.types.*;
 import static org.neo4j.driver.v1.Values.parameters;
 import java.util.*;
 
-public class test {
+public class Basic {
     public static void main(String[] args) {
         Config config = Config.build().withoutEncryption().toConfig();
         Driver driver = GraphDatabase.driver( "bolt://localhost:7687", AuthTokens.basic( "neo4j", "1234" ), config );

tests/drivers/java/MaxQueryLength.java

@@ -0,0 +1,59 @@
+/**
+ * Determines how long could be a query executed
+ * from Java driver.
+ *
+ * Performs binary search until the maximum possible
+ * query size has found.
+ */
+
+import java.util.*;
+
+import org.neo4j.driver.v1.*;
+import org.neo4j.driver.v1.types.*;
+import static org.neo4j.driver.v1.Values.parameters;
+
+public class MaxQueryLength {
+    public static void main(String[] args) {
+        // init driver
+        Config config = Config.build().withoutEncryption().toConfig();
+        Driver driver = GraphDatabase.driver("bolt://localhost:7687",
+                                             AuthTokens.basic( "", "" ),
+                                             config);
+        // init query
+        int property_size = 0;
+        int min_len = 1;
+        int max_len = 100000;
+        String query_template = "CREATE (n {name:\"%s\"})";
+        int template_size = query_template.length() - 2; // because of %s
+
+        // binary search
+        while (true) {
+            property_size = (max_len + min_len) / 2;
+            try (Session session = driver.session()) {
+                String property_value = new String(new char[property_size])
+                    .replace('\0', 'a');
+                String query = String.format(query_template, property_value);
+                session.run(query).consume();
+                if (min_len == max_len || property_size + 1 > max_len) {
+                    break;
+                }
+                min_len = property_size + 1;
+            }
+            catch (Exception e) {
+                System.out.println(String.format(
+                    "Query length: %d; Error: %s",
+                    property_size + template_size, e));
+                max_len = property_size - 1;
+            }
+        }
+
+        // final result
+        System.out.println(
+            String.format("\nThe max length of a query executed from " +
+                          "Java driver is: %s\n",
+                          property_size + template_size));
+
+        // cleanup
+        driver.close();
+    }
+}

tests/drivers/java/run.sh

@@ -1,5 +1,7 @@
 #!/bin/bash
 
+set -e
+
 JAVA=java
 JAVAC=javac
 
@@ -19,5 +21,8 @@ if [ ! -f $DRIVER ]; then
     wget -O $DRIVER http://central.maven.org/maven2/org/neo4j/driver/neo4j-java-driver/1.3.1/neo4j-java-driver-1.3.1.jar || exit 1
 fi
 
-javac -classpath .:$DRIVER test.java || exit 1
-java -classpath .:$DRIVER test || exit 1
+javac -classpath .:$DRIVER Basic.java
+java -classpath .:$DRIVER Basic
+
+javac -classpath .:$DRIVER MaxQueryLength.java
+java -classpath .:$DRIVER MaxQueryLength

tests/drivers/javascript/max_query_length.js

@@ -0,0 +1,51 @@
+// Determines how long could be a query executed
+// from JavaScript driver.
+//
+// Performs binary search until the maximum possible
+// query size has found.
+
+// init driver
+var neo4j = require('neo4j-driver').v1;
+var driver = neo4j.driver("bolt://localhost:7687",
+                          neo4j.auth.basic("", ""),
+                          { encrypted: 'ENCRYPTION_OFF' });
+
+// init state
+var property_size = 0;
+var min_len = 1;
+var max_len = 1000000;
+
+// hacking with JS and callbacks concept
+function serial_execution() {
+  var next_size = [Math.floor((min_len + max_len) / 2)];
+  setInterval(function() {
+    if (next_size.length > 0) {
+      property_size = next_size.pop();
+      var query = "CREATE (n {name:\"" +
+        (new Array(property_size)).join("a")+ "\"})";
+      var session = driver.session();
+      session.run(query, {}).then(function (result) {
+        console.log("Success with the query length " + query.length);
+        if (min_len == max_len || property_size + 1 > max_len) {
+          console.log("\nThe max length of a query from JS driver is: " +
+            query.length + "\n");
+          session.close();
+          driver.close();
+          process.exit(0);
+        }
+        min_len = property_size + 1;
+        next_size.push(Math.floor((min_len + max_len) / 2));
+      }).catch(function (error) {
+        console.log("Failure with the query length " + query.length);
+        max_len = property_size - 1;
+        next_size.push(Math.floor((min_len + max_len) / 2));
+      }).then(function(){
+        session.close();
+      });
+    }
+  }, 100);
+}
+
+// execution
+console.log("\nDetermine how long can be a query sent from JavaScript driver.");
+serial_execution(); // I don't like JavaScript

tests/drivers/javascript/run.sh

@@ -1,5 +1,7 @@
 #!/bin/bash
 
+set -e
+
 NODE=nodejs
 NPM=npm
 
@@ -13,5 +15,7 @@ if ! which $NPM >/dev/null; then
     exit 1
 fi
 
-$NPM install neo4j-driver || exit 1
-$NODE test.js || exit 1
+$NPM install neo4j-driver
+
+$NODE basic.js
+$NODE max_query_length.js

tests/drivers/python/max_query_length.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+from neo4j.v1 import GraphDatabase, basic_auth
+
+driver = GraphDatabase.driver("bolt://localhost:7687",
+                              auth=basic_auth("", ""),
+                              encrypted=False)
+
+query_template = 'CREATE (n {name:"%s"})'
+template_size = len(query_template) - 2  # because of %s
+min_len = 1
+max_len = 1000000
+
+# binary search because we have to find the maximum size (in number of chars)
+# of a query that can be executed via driver
+while True:
+    assert min_len > 0 and max_len > 0, \
+        "The lengths have to be positive values! If this happens something" \
+        " is terrible wrong with min & max lengths OR the database" \
+        " isn't available."
+    property_size = (max_len + min_len) // 2
+    try:
+        driver.session().run(query_template % ("a" * property_size)).consume()
+        if min_len == max_len or property_size + 1 > max_len:
+            break
+        min_len = property_size + 1
+    except Exception as e:
+        print("Query size %s is too big!" % (template_size + property_size))
+        max_len = property_size - 1
+
+assert property_size == max_len, "max_len probably has to be increased!"
+
+print("\nThe max length of a query from Python driver is: %s\n" %
+      (template_size + property_size))
+
+# sessions are not closed bacause all sessions that are
+# executed with wrong query size might be broken
+driver.close()

tests/drivers/python/run.sh

@@ -1,12 +1,12 @@
 #!/bin/bash
 
+set -e
+
 VIRTUALENV=virtualenv
 PIP=pip
 PYTHON=python
 WORKING_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
-set -e
-
 cd ${WORKING_DIR}
 
 # system check
@@ -17,11 +17,12 @@ fi
 
 # setup virtual environment
 if [ ! -d "ve3" ]; then
-    virtualenv -p python3 ve3
+    virtualenv -p python3 ve3 || exit 1
 fi
 source ve3/bin/activate
 $PIP install --upgrade pip
 $PIP install neo4j-driver
 
 # execute test
-$PYTHON test.py
+$PYTHON basic.py
+$PYTHON max_query_length.py