---
id: dd27e2d1-98c4-4c22-9a0e-a64f8b0d42df
---

# Airflow Connection Pool Exhaustion Incident
---

Apache Airflow connection pool exhaustion incident refers to a situation where the connection pool of Apache Airflow, a popular open-source platform to programmatically create, schedule, and monitor workflows, becomes exhausted and unable to handle additional requests. This can lead to a variety of issues, including slow performance, timeouts, and failures in task execution. The incident can impact the overall productivity and efficiency of the workflows running on the Apache Airflow platform. This type of incident is typically resolved by identifying the root cause of the connection pool exhaustion and implementing measures to optimize connection management, such as increasing the pool size or reducing the connection timeout.

### Parameters
```shell
export PATH_TO_AIRFLOW_CONFIG="PLACEHOLDER"

export DESIRED_POOL_SIZE="PLACEHOLDER"

export PATH_TO_AIRFLOW_HOME_DIRECTORY="PLACEHOLDER"

export PATH_TO_AIRFLOW_LOG_FILE="PLACEHOLDER"

export EXPECTED_NUMBER_OF_CONNECTIONS="PLACEHOLDER"
```

## Debug

### 1. Check the system resource utilization
```shell
top
```

### 2. Check the Apache Airflow process status
```shell
systemctl status airflow-webserver
```

### 3. Check the Apache Airflow logs for any connection pool-related errors
```shell
grep "connection pool" /var/log/airflow/*.log
```

### 4. Check the current number of connections in the pool
```shell
pgrep -f airflow | xargs -I {} sh -c 'echo -n {}" "; ps -eo pid,cmd | grep {} | grep -v grep | awk "{print \$1}" | xargs -I {} sh -c "echo -n ' '; lsof -p {} | grep airflow | grep -c ESTABLISHED"'
```

### 5. Check the Apache Airflow configuration for connection pool settings
```shell
cat ${PATH_TO_AIRFLOW_CONFIG}/airflow.cfg | grep -i connection_pool
```

### 6. Monitor the system and Apache Airflow processes for connection pool exhaustion
```shell
watch -n 1 "pgrep -f airflow | xargs -I {} sh -c 'echo -n {}\" \"; ps -eo pid,cmd | grep {} | grep -v grep | awk \"{print \$1}\" | xargs -I {} sh -c \"echo -n ' '; lsof -p {} | grep airflow | grep -c ESTABLISHED\"'"
```

### High traffic: A sudden surge in user traffic or an increase in the number of workflow tasks can put a strain on the connection pool and lead to exhaustion.
```shell
bash

#!/bin/bash



# Set variables

AIRFLOW_HOME=${PATH_TO_AIRFLOW_HOME_DIRECTORY}

LOG_FILE=${PATH_TO_AIRFLOW_LOG_FILE}

CONNECTIONS=${EXPECTED_NUMBER_OF_CONNECTIONS}



# Get current number of connections

CURRENT_CONNECTIONS=$(psql -h localhost -p 5432 -U postgres -d airflow -c "SELECT COUNT(*) FROM connection;" | grep -o '[0-9]*')



# Compare current number of connections with expected number of connections

if [ "$CURRENT_CONNECTIONS" -gt "$CONNECTIONS" ]; then

    # Log message

    echo "$(date) - High traffic causing connection pool exhaustion" >> "$LOG_FILE"



    # Restart Airflow services

    sudo systemctl restart airflow-webserver

    sudo systemctl restart airflow-scheduler

else

    # Log message

    echo "$(date) - Connection pool is healthy" >> "$LOG_FILE"

fi


```

## Repair

### Increase the connection pool size: One of the most common remediation strategies for connection pool exhaustion is to increase the pool size. This can be done by modifying the configuration settings of the Apache Airflow platform to allocate more resources to the connection pool.
```shell


#!/bin/bash



# Set the path to the Apache Airflow configuration file

CONFIG_FILE=${PATH_TO_AIRFLOW_CONFIG}



# Set the desired pool size

POOL_SIZE=${DESIRED_POOL_SIZE}



# Update the connection pool size in the configuration file

sed -i "s/^parallelism = .*/parallelism = $POOL_SIZE/" $CONFIG_FILE



# Restart Apache Airflow

sudo systemctl restart airflow-webserver

sudo systemctl restart airflow-scheduler


```


Apache Airflow connection pool exhaustion incident refers to a situation where the connection pool of Apache Airflow, a popular open-source platform to programmatically create, schedule, and monitor workflows, becomes exhausted and unable to handle additional requests. This can lead to a variety of issues, including slow performance, timeouts, and failures in task execution. The incident can impact the overall productivity and efficiency of the workflows running on the Apache Airflow platform. This type of incident is typically resolved by identifying the root cause of the connection pool exhaustion and implementing measures to optimize connection management, such as increasing the pool size or reducing the connection timeout.


When too many requests are sent to a Tomcat server, the thread pools that handle these requests can run out of available threads. This means that incoming requests will not be processed, leading to service degradation or even a complete outage. This incident type is critical for web applications that rely on Tomcat as their application server.


Tomcat thread pool exhaustion.

This incident type is related to the Tomcat server, which is a popular open-source Java application server. It occurs when the available threads in the connection pool are running low, which means that there are not enough resources to serve incoming requests. This can cause delays or even failures in the application's performance, impacting the end-user experience. It is important to monitor and address this issue promptly to ensure that the application runs smoothly and efficiently.


Tomcat Low Available Threads in Connection Pool

This incident type refers to a situation where the Tomcat server's JDBC connection pool usage surpasses its configured limits. This can lead to a shortage of available connections for incoming requests, resulting in slow response times or even server crashes. It is important to monitor and manage the JDBC connection pool usage to prevent such incidents from occurring.


Tomcat High JDBC Connection Pool Usage Incident.

Tomcat Connection Pool Exhaustion Incident occurs when the maximum number of connections that a Tomcat server can handle has been reached. This can happen due to an increase in traffic or a sudden surge in user activity. When the connection pool is exhausted, new requests cannot be handled, and the application may become unavailable. This type of incident requires immediate attention to ensure that the application is restored to its normal functioning state.


Tomcat Connection Pool Exhaustion Incident

This incident type occurs when the number of concurrent connections to a MySQL database server exceeds the configured limit of 80%. This can lead to performance degradation or even database server crashes, making the application or system that relies on the database server unavailable for the end-users. This type of incident typically requires immediate attention and resolution to restore normal operation of the affected service.


MySQL too many connections incident

```shell
export PATH_TO_AIRFLOW_CONFIG="PLACEHOLDER"

export DESIRED_POOL_SIZE="PLACEHOLDER"

export PATH_TO_AIRFLOW_HOME_DIRECTORY="PLACEHOLDER"

export PATH_TO_AIRFLOW_LOG_FILE="PLACEHOLDER"

export EXPECTED_NUMBER_OF_CONNECTIONS="PLACEHOLDER"
```


### 1. Check the system resource utilization

```shell
top
```

### 2. Check the Apache Airflow process status

```shell
systemctl status airflow-webserver
```

### 3. Check the Apache Airflow logs for any connection pool-related errors

```shell
grep "connection pool" /var/log/airflow/*.log
```

### 4. Check the current number of connections in the pool

```shell
pgrep -f airflow | xargs -I {} sh -c 'echo -n {}" "; ps -eo pid,cmd | grep {} | grep -v grep | awk "{print \$1}" | xargs -I {} sh -c "echo -n ' '; lsof -p {} | grep airflow | grep -c ESTABLISHED"'
```

### 5. Check the Apache Airflow configuration for connection pool settings

```shell
cat ${PATH_TO_AIRFLOW_CONFIG}/airflow.cfg | grep -i connection_pool
```

### 6. Monitor the system and Apache Airflow processes for connection pool exhaustion

```shell
watch -n 1 "pgrep -f airflow | xargs -I {} sh -c 'echo -n {}\" \"; ps -eo pid,cmd | grep {} | grep -v grep | awk \"{print \$1}\" | xargs -I {} sh -c \"echo -n ' '; lsof -p {} | grep airflow | grep -c ESTABLISHED\"'"
```

### High traffic: A sudden surge in user traffic or an increase in the number of workflow tasks can put a strain on the connection pool and lead to exhaustion.

```shell
bash

#!/bin/bash



# Set variables

AIRFLOW_HOME=${PATH_TO_AIRFLOW_HOME_DIRECTORY}

LOG_FILE=${PATH_TO_AIRFLOW_LOG_FILE}

CONNECTIONS=${EXPECTED_NUMBER_OF_CONNECTIONS}



# Get current number of connections

CURRENT_CONNECTIONS=$(psql -h localhost -p 5432 -U postgres -d airflow -c "SELECT COUNT(*) FROM connection;" | grep -o '[0-9]*')



# Compare current number of connections with expected number of connections

if [ "$CURRENT_CONNECTIONS" -gt "$CONNECTIONS" ]; then

    # Log message

    echo "$(date) - High traffic causing connection pool exhaustion" >> "$LOG_FILE"



    # Restart Airflow services

    sudo systemctl restart airflow-webserver

    sudo systemctl restart airflow-scheduler

else

    # Log message

    echo "$(date) - Connection pool is healthy" >> "$LOG_FILE"

fi


```


### Increase the connection pool size: One of the most common remediation strategies for connection pool exhaustion is to increase the pool size. This can be done by modifying the configuration settings of the Apache Airflow platform to allocate more resources to the connection pool.

```shell


#!/bin/bash



# Set the path to the Apache Airflow configuration file

CONFIG_FILE=${PATH_TO_AIRFLOW_CONFIG}



# Set the desired pool size

POOL_SIZE=${DESIRED_POOL_SIZE}



# Update the connection pool size in the configuration file

sed -i "s/^parallelism = .*/parallelism = $POOL_SIZE/" $CONFIG_FILE



# Restart Apache Airflow

sudo systemctl restart airflow-webserver

sudo systemctl restart airflow-scheduler


```


Airflow Connection Pool Exhaustion Incident

Overview

Parameters

Debug

1. Check the system resource utilization

2. Check the Apache Airflow process status

4. Check the current number of connections in the pool

5. Check the Apache Airflow configuration for connection pool settings

6. Monitor the system and Apache Airflow processes for connection pool exhaustion

High traffic: A sudden surge in user traffic or an increase in the number of workflow tasks can put a strain on the connection pool and lead to exhaustion.

Repair

Increase the connection pool size: One of the most common remediation strategies for connection pool exhaustion is to increase the pool size. This can be done by modifying the configuration settings of the Apache Airflow platform to allocate more resources to the connection pool.

Learn more

Related Runbooks

Tomcat thread pool exhaustion.

Tomcat Low Available Threads in Connection Pool

Tomcat High JDBC Connection Pool Usage Incident.

Tomcat Connection Pool Exhaustion Incident

Support