Error :

sqlalchemy.exc.TimeoutError: QueuePool limit of size 5 overflow 10 reached, connection timed out, timeout 30.00

Reason :

The timeout occurs due to the open connection.

  • You must ensure that your sessions are closed; otherwise, they will keep your connections open and never return to the pool.
  • log your pool status at some points, so that you can see how many connections are open.

To close sessions:




Issue : Following is a build error received when building a CAR project.

[ERROR] Failed to execute goal org.wso2.maven:wso2-esb-api-plugin:2.1.0:pom-gen (api) on project TESTESB: Execution api of goal org.wso2.maven:wso2-esb-api-plugin:2.1.0:pom-gen failed: A required class was missing while executing org.wso2.maven:wso2-esb-api-plugin:2.1.0:pom-gen: javax/activation/DataSource
[ERROR] -----------------------------------------------------
[ERROR] realm = extension>org.wso2.maven:wso2-esb-api-plugin:2.1.0
[ERROR] strategy = org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy
Environment setup => java version : 17.0.1
maven version : Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f)
operating system : macOS Big Sur

Cause and resolution:

In this case of Maven, we specify the compiler plugin to use Maven with Java 17. Here the plugin does not support Java 17 which causes the issue. Downgraded the java version to the most commonly used java version “1.8.0_301" which resolved the issue.



Issue : Following is an error received when connecting PostgreSQL and Flutter. The error occurs when trying to connect through the android emulator in a development environment.

E/flutter ( 8084): [ERROR:flutter/lib/ui/] Unhandled Exception: SocketException: OS Error: Connection refused, errno = 111, address = localhost, port = 43992

Solution :

  1. Make sure you have given internet permission in your app’s by adding the following lines in the android/app/src/main/AndroidManifest.xml file
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

2. Replace localhost with or android emulator)



Given the following soap message the use case it to extract only the elements of the body (exclude the soap envelope and body tags). Following is the XML message in which the content is needed to be extracted from.

<?xml version="1.0" encoding="UTF-8"?> <soapenv:Envelope xmlns:soapenv="">    <soapenv:Body>       
<EventIdentification EventActionCode="U" EventDateTime="not specialized" EventOutcomeIndicator="not specialized">

Use the following expression to extract the content in the body

<property expression="$body/*" name="syslogMessage"
scope="default" type="STRING"
xmlns:ns="http://org.apache.synapse/xsd" xmlns:ns2="http://org.apache.synapse/xsd"/>

The output is as follows,

<EventIdentification EventActionCode="U" EventDateTime="not specialized" EventOutcomeIndicator="not specialized">