KB-1431 "Unable to acquire a Read/Write connection. Safe to retry."

Parmida Borhani — Wed, 04 Sep 2019 07:02:40 GMT

Current Revision posted to Appian Knowledge Base by Parmida Borhani on 9/4/2019 7:02:40 AM

Symptoms

At least once of the following messages in seen in the application server log:

ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: process-analytics0 (<HOSTNAME>:5018)
ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: process-analytics1 (<HOSTNAME>:5020)
ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: process-analytics2 (<HOSTNAME>:5022)
ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: process-execution0 (<HOSTNAME>:5024)
ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: process-execution1 (<HOSTNAME>:5026)
ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: process-execution2 (<HOSTNAME>:5028)
ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: personalization (<HOSTNAME>:5012)
ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: portal (<HOSTNAME>:5014)
ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: process-design (<HOSTNAME>:5016)
ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: content (<HOSTNAME>:5008)
ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: collaboration-statistics (<HOSTNAME>:5010)
ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: notify (<HOSTNAME>:5002)
ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: notify-email (<HOSTNAME>:5004)
ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: content (<HOSTNAME>:5008)
ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: channels (<HOSTNAME>:5006)
ERROR com.appiancorp.kougar.driver.ipc.IpcConnection - Failure to read socket: forums (<HOSTNAME>:5000)

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

This message indicates that the application server sent a request to a particular engine, but did not receive a response within an acceptable time frame. When this error is encountered, it may mean the engine is busy at that time, or that the application server was unable to connect to the engine.

Action

To check the responsiveness, availability, and status of the Appian engine servers, run the appropriate script based on the Appian version.
Appian 17.2 and prior

Run the checkengine script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

Appian 17.3 and above

Run the status script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/services/bin/status.bat|.sh.
If the engines are up and running without any issues, the error message is simply indicating that the particular request could not be handled at the time because the engine is busy processing work. The request will be retried again once resources are freed up. Review the performance logs from the time that the error was encountered to see if there was an unusually high load on the system.
If the application server and engines are not running on the same server, check that the appian-topology.xml is consistent across all servers.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: September 2019

Tags: engines, infrastructure

KB-1431 "Unable to acquire a Read/Write connection. Safe to retry."

Parmida Borhani — Mon, 23 Jul 2018 03:36:00 GMT

Revision 20 posted to Appian Knowledge Base by Parmida Borhani on 7/23/2018 3:36:00 AM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

Action

To check the responsiveness, availability, and status of the Appian engine servers, run the appropriate script based on the Appian version.
Appian 17.2 and prior

Run the checkengine script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

Appian 17.3 and above

Run the status script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/services/bin/status.bat|.sh.
If the engines are up and running without any issues, the error message is simply indicating that the particular request could not be handled at the time because the engine is busy processing work. The request will be retried again once resources are freed up. Review the performance logs from the time that the error was encountered to see if there was an unusually high load on the system.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines, infrastructure

KB-1431 "Unable to acquire a Read/Write connection. Safe to retry."

Parmida Borhani — Tue, 05 Dec 2017 02:29:57 GMT

Revision 19 posted to Appian Knowledge Base by Parmida Borhani on 12/5/2017 2:29:57 AM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

Action

To check the responsiveness, availability, and status of the Appian engine servers, run the appropriate script based on the Appian version.
Appian 17.2 and prior

Run the checkengine script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

Appian 17.3 and above

Run the status script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/services/bin/status.bat|.sh.
If the engines are up and running without any issues, the error message is simply indicating that the particular request could not be handled at the time because the engine is busy processing work. The request will be retried again once resources are freed up. Review the performance logs from the time that the error was encountered to see if there was an unusually high load on the system.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-1431 "Unable to acquire a Read/Write connection. Safe to retry."

Parmida Borhani — Mon, 04 Dec 2017 21:24:04 GMT

Revision 18 posted to Appian Knowledge Base by Parmida Borhani on 12/4/2017 9:24:04 PM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

This message indicates that the application server sent a request to a particular engine, but did not receive a response within an acceptable time frame. This error is often seen when starting up an environment. It can also be seen at other times when the environment is already up and running, but there is a high load on the system.

Action

To check the responsiveness, availability, and status of the Appian engine servers, run the appropriate script based on the Appian version.
Appian 17.2 and prior

Run the checkengine script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

Appian 17.3 and above

Run the status script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/services/bin/status.bat|.sh.
If the engines are up and running without any issues, the error message is simply indicating that the particular request could not be handled at the time because the engine is busy processing work. The request will be retried again once resources are freed up. Review the performance logs from the time that the error was encountered to see if there was an unusually high load on the system.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-1431 "Unable to acquire a Read/Write connection. Safe to retry."

Nick Vigilante — Mon, 04 Dec 2017 08:27:07 GMT

Revision 17 posted to Appian Knowledge Base by Nick Vigilante on 12/4/2017 8:27:07 AM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

This message indicates that a particular engine received a request to do something, but did not receive a response within an acceptable time frame. This error is often seen when starting up an environment. It can also be seen at other times when the environment is already up and running, but there is a high load on the system. Any of the following are reasons why this message could be seen in the logs:

The engine that threw the error was busy.
Another engine that received the request from the engine that threw the error was busy.
The application server was busy.

Action

To check the responsiveness, availability, and status of the Appian engine servers, run the appropriate script based on the Appian version.
Appian 17.2 and prior

Run the checkengine script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

Appian 17.3 and above

Run the status script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/services/bin/status.bat|.sh.
If the engines are up and running without any issues, the error message is simply indicating that the particular request could not be handled at the time because the system is busy processing work. The request will be retried again once resources are freed up. Review the performance logs from the time that the error was encountered to see if there was an unusually high load on the system.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-1431 "Unable to acquire a Read/Write connection. Safe to retry."

Nick Vigilante — Mon, 04 Dec 2017 08:25:17 GMT

Revision 16 posted to Appian Knowledge Base by Nick Vigilante on 12/4/2017 8:25:17 AM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

The engine that threw the error was busy.
Another engine that received the request from the engine that threw the error was busy.
The application server was busy.

Action

To check the responsiveness, availability, and status of the Appian engine servers, run the appropriate script based on the Appian version.
Appian 17.2 and prior

Run the checkengine script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

Appian 17.3 and above

Run the status script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/services/bin/status.bat|.sh.
If the engines are up and running without any issues, the error message is simply indicating that the particular request could not be handled at the time because the system is busy processing work. The request will be retried again once resources are freed up. Review the performance logs from the time that the error was encountered to see if there was an unusually high load on the system.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-1431 "Unable to acquire a Read/Write connection. Safe to retry."

Nick Vigilante — Mon, 04 Dec 2017 08:24:47 GMT

Revision 15 posted to Appian Knowledge Base by Nick Vigilante on 12/4/2017 8:24:47 AM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

The engine that threw the error was busy.
Another engine that received the request from the engine that threw the error was busy.
The application server was busy.

Action

To check the responsiveness, availability, and status of the Appian engine servers, run the appropriate script based on the Appian version.
Appian 17.2 and prior

Run the checkengine script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

Appian 17.3 and above

Run the status script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/services/bin/status.bat|.sh.
If the engines are up and running without any issues, the error message is simply indicating that the particular request could not be handled at the time because the system is busy processing work. The request will be retried again once resources are freed up. Review the performance logs from the time that the error was encountered to see if there was an unusually high load on the system.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-1431 "Unable to acquire a Read/Write connection. Safe to retry."

Nick Vigilante — Mon, 04 Dec 2017 08:24:14 GMT

Revision 14 posted to Appian Knowledge Base by Nick Vigilante on 12/4/2017 8:24:14 AM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

The engine that threw the error was busy.
Another engine that received the request from the engine that threw the error was busy.
The application server was busy.

Action

To check the responsiveness, availability, and status of the Appian engine servers, run the appropriate script based on the Appian version.
Appian 17.2 and prior

Run the checkengine script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

Appian 17.3 and above

Run the status script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/services/bin/status.bat|.sh.
If the engines are up and running without any issues, the error message is simply indicating that the particular request could not be handled at the time because the system is busy processing work. The request will be retried again once resources are freed up. Review the performance logs from the time that the error was encountered to see if there was an unusually high load on the system.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-XXXX Unable to acquire a Read connection. Safe to retry

Parmida Borhani — Mon, 04 Dec 2017 00:16:44 GMT

Revision 1 posted to Appian Knowledge Base by Parmida Borhani on 12/4/2017 12:16:44 AM

Symptoms

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry

Cause

This error is often seen when starting up an environment. However, it can also be seen at other times when the environment is already up and running.

This error indicates your app server is unable to communicate with the engines.

This likely indicates that an Appian engine was too busy to handle the original request from the app server within a reasonable amount of time. As the error indicated, the request was safe to retry. So, as expected, once the necessary resources were freed up, and you retried, the request completed successfully.

Action

If you are running Appian version 17.2 or prior, run the checkengine script: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh

If you are running Appian version 17.3 or above, run the status script: <APPIAN_HOME>/services/bin/status.bat|.sh

I would recommend that you review the performance logs from the time that you encountered the error to see if there was an unusually high load on the system. Based on that information, it may be worthwhile to factor that amount of resource utilization into your application design and/or architecture.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-1431 "Unable to acquire a Read/Write connection. Safe to retry."

Parmida Borhani — Sun, 03 Dec 2017 22:20:34 GMT

Revision 13 posted to Appian Knowledge Base by Parmida Borhani on 12/3/2017 10:20:34 PM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

The engine that threw the error was busy.
Another engine that received the request from the engine that threw the error was busy.
The application server was busy.

Action

To check the responsiveness, availability, and status of the Appian engine servers, run the appropriate script based on the Appian version.
Appian 17.2 and prior

Run the checkengine script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

Appian 17.3 and above

Run the status script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/services/bin/status.bat|.sh.
If the engines are up and running without any issues, the error message is simply indicating that the particular request could not be handled at the time because the system is busy processing work. The request will be retried again once resources are freed up. Review the performance logs from the time that the error was encountered to see if there was an unusually high load on the system.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-XXXX "Unable to acquire a Read/Write connection. Safe to retry."

Parmida Borhani — Sun, 03 Dec 2017 20:24:07 GMT

Revision 12 posted to Appian Knowledge Base by Parmida Borhani on 12/3/2017 8:24:07 PM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

The engine that threw the error was busy.
Another engine that received the request from the engine that threw the error was busy.
The application server was busy.

Action

To check the responsiveness, availability, and status of the Appian engine servers, run the appropriate script based on the Appian version.
Appian 17.2 and prior

Run the checkengine script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

Appian 17.3 and above

Run the status script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/services/bin/status.bat|.sh.
If the engines are up and running without any issues, the error message is simply indicating that the particular request could not be handled at the time because the system is busy processing work. The request will be retried again once resources are freed up. Review the performance logs from the time that the error was encountered to see if there was an unusually high load on the system.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-XXXX "Unable to acquire a Read/Write connection. Safe to retry."

Parmida Borhani — Sun, 03 Dec 2017 20:21:07 GMT

Revision 11 posted to Appian Knowledge Base by Parmida Borhani on 12/3/2017 8:21:07 PM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

The engine that threw the error was busy.
Another engine that received the request from the engine that threw the error was busy.
The application server was busy.

Action

To check the responsiveness, availability, and status of the Appian engine servers, run the appropriate script based on the Appian version.
Appian 17.2 and prior

Run the checkengine script to diagnose any potential engine related issues and work to resolve them based on the documentation:

<APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

Appian 17.3 and above

Run the status script to diagnose any potential engine related issues and work to resolve them based on the documentation:

<APPIAN_HOME>/services/bin/status.bat|.sh.
If the engines are up and running without any issues, the error message is simply indicating that the particular request could not be handled at the time because the system is busy processing work. The request will be retried again once resources are freed up. Review the performance logs from the time that the error was encountered to see if there was an unusually high load on the system.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-XXXX "Unable to acquire a Read/Write connection. Safe to retry."

Parmida Borhani — Sun, 03 Dec 2017 20:19:52 GMT

Revision 10 posted to Appian Knowledge Base by Parmida Borhani on 12/3/2017 8:19:52 PM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

The engine that threw the error was busy.
Another engine that received the request from the engine that threw the error was busy.
The application server was busy.

Action

To check the responsiveness, availability, and status of the Appian engine servers, run the appropriate script based on the Appian version.

Appian 17.2 and prior

Run the checkengine script to diagnose any potential engine related issues and work to resolve them based on the documentation:

<APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

Appian 17.3 and above

Run the status script to diagnose any potential engine related issues and work to resolve them based on the documentation:

<APPIAN_HOME>/services/bin/status.bat|.sh.

If the engines are up and running without any issues, the error message is simply indicating that the particular request could not be handled at the time because the system is busy processing work. The request will be retried again once resources are freed up. Review the performance logs from the time that the error was encountered to see if there was an unusually high load on the system.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-XXXX "Unable to acquire a Read/Write connection. Safe to retry."

Parmida Borhani — Sun, 03 Dec 2017 20:17:05 GMT

Revision 9 posted to Appian Knowledge Base by Parmida Borhani on 12/3/2017 8:17:05 PM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

The engine that threw the error was busy.
Another engine that received the request from the engine that threw the error was busy.
The application server was busy.

Action

If you are running Appian version 17.2 or prior, run the checkengine script to diagnose any potential engine related issues and work to resolve them based on the documentation:

<APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

If you are running Appian version 17.3 or above, run the status script to diagnose any potential engine related issues and work to resolve them based on the documentation:

<APPIAN_HOME>/services/bin/status.bat|.sh.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-XXXX "Unable to acquire a Read/Write connection. Safe to retry."

Parmida Borhani — Sun, 03 Dec 2017 20:16:01 GMT

Revision 8 posted to Appian Knowledge Base by Parmida Borhani on 12/3/2017 8:16:01 PM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

The engine that threw the error was busy.
Another engine that received the request from the engine that threw the error was busy.
The application server was busy.

Action

If you are running Appian version 17.2 or prior, run the checkengine script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

If you are running Appian version 17.3 or above, run the status script to diagnose any potential engine related issues and work to resolve them based on the documentation: <APPIAN_HOME>/services/bin/status.bat|.sh.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-XXXX "Unable to acquire a Read/Write connection. Safe to retry."

Parmida Borhani — Sun, 03 Dec 2017 19:35:23 GMT

Revision 7 posted to Appian Knowledge Base by Parmida Borhani on 12/3/2017 7:35:23 PM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

The engine that threw the error was busy.
Another engine that received the request from the engine that threw the error was busy.
The application server was busy.

Action

If you are running Appian version 17.2 or prior, run the checkengine script to diagnose any potential engine related issues: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

If you are running Appian version 17.3 or above, run the status script to diagnose any potential engine related issues: <APPIAN_HOME>/services/bin/status.bat|.sh.

https://docs.appian.com/suite/help/17.4/Status_Script.html

If there is an issue with any of the engines, work to resolve the issues based on the documentation.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-XXXX "Unable to acquire a Read/Write connection. Safe to retry."

Parmida Borhani — Sun, 03 Dec 2017 19:32:08 GMT

Revision 6 posted to Appian Knowledge Base by Parmida Borhani on 12/3/2017 7:32:08 PM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

The engine that threw the error was busy.
Another engine that received the request from the engine that threw the error was busy.
The application server was busy.

Action

If you are running Appian version 17.2 or prior, run the checkengine script to diagnose any potential engine related issues: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

If you are running Appian version 17.3 or above, run the status script to diagnose any potential engine related issues: <APPIAN_HOME>/services/bin/status.bat|.sh.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-XXXX "Unable to acquire a Read/Write connection. Safe to retry."

Parmida Borhani — Sun, 03 Dec 2017 19:31:03 GMT

Revision 5 posted to Appian Knowledge Base by Parmida Borhani on 12/3/2017 7:31:03 PM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

This message indicates that a particular engine received a request to do something, but did not receive a response within an acceptable time frame. This error is often seen when starting up an environment. It can also be seen at other times when the environment is already up and running, but there is a high load on the engines/the engines are busy processing work. Any of the following reasons could be reasons why this message in seen in the logs:

The engine that threw the error was busy.
Another engine that received the request from the engine that threw the error was busy.
The application server was busy.

Action

If you are running Appian version 17.2 or prior, run the checkengine script to diagnose any potential engine related issues: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

If you are running Appian version 17.3 or above, run the status script to diagnose any potential engine related issues: <APPIAN_HOME>/services/bin/status.bat|.sh.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-XXXX "Unable to acquire a Read/Write connection. Safe to retry."

Parmida Borhani — Sun, 03 Dec 2017 19:26:02 GMT

Revision 4 posted to Appian Knowledge Base by Parmida Borhani on 12/3/2017 7:26:02 PM

Symptoms

At least once of the following messages in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Write connection. Safe to retry.

Cause

The error indicates that the application server is unable to communicate with the engines within a reasonable amount of time. This error is often seen when starting up an environment. It can also be seen at other times when the environment is already up and running, but there is a high load on the engines/the engines are busy processing work.

An engine received a request to do something (this engine is usually named somewhere near one of the above messages), but did not receive a response within an acceptable time frame. This is most likely due to one of the following reasons:

The engine that threw the error was busy.
Another engine that received the request from the engine that threw the error was busy.
The application server was busy.

Action

If you are running Appian version 17.2 or prior, run the checkengine script to diagnose any potential engine related issues: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

If you are running Appian version 17.3 or above, run the status script to diagnose any potential engine related issues: <APPIAN_HOME>/services/bin/status.bat|.sh.

If the engines are up and running without any issues, the error message is simply indicating that the particular request could not be handled at the time because the engines are busy processing work and will be retried later once resources are freed up. Review the performance logs from the time that the error was encountered to see if there was an unusually high load on the system.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-XXXX Unable to acquire a Read connection. Safe to retry

Parmida Borhani — Sun, 03 Dec 2017 19:23:41 GMT

Revision 3 posted to Appian Knowledge Base by Parmida Borhani on 12/3/2017 7:23:41 PM

Symptoms

The following error in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

Cause

Action

If you are running Appian version 17.2 or prior, run the checkengine script to diagnose any potential engine related issues: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

If you are running Appian version 17.3 or above, run the status script to diagnose any potential engine related issues: <APPIAN_HOME>/services/bin/status.bat|.sh.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines

KB-XXXX Unable to acquire a Read connection. Safe to retry

Parmida Borhani — Sun, 03 Dec 2017 19:20:58 GMT

Revision 2 posted to Appian Knowledge Base by Parmida Borhani on 12/3/2017 7:20:58 PM

Symptoms

The following error in seen in the application server log:

com.appiancorp.kougar.driver.exceptions.SafeRetryException: Unable to acquire a Read connection. Safe to retry.

Cause

Action

If you are running Appian version 17.2 or prior, run the checkengine script: <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat|.sh.

If you are running Appian version 17.3 or above, run the status script: <APPIAN_HOME>/services/bin/status.bat|.sh.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: December 2017

Tags: engines