---
id: c352ec61-5faa-4428-ba21-57fca192ebaf
---

# Redis Cache Invalidation Incident.
---

Redis Cache Invalidation Incident refers to the situation where the Redis cache which is a key-value data store, fails to invalidate or remove data that has been modified or deleted in the primary data store. This can lead to inconsistencies and errors in the application that relies on the cache for faster data retrieval. The incident requires the identification of the root cause and the implementation of a solution to ensure that the cache stays in sync with the primary data store.

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

export PATH_TO_REDIS_CONFIG_FILE="PLACEHOLDER"

export CACHE_EVICTION_POLICY="PLACEHOLDER"
```

## Debug

### Check Redis server is running
```shell
systemctl status redis-server
```

### Check connection to Redis server
```shell
redis-cli ping
```

### Check Redis keys
```shell
redis-cli keys *
```

### Check Redis cache size
```shell
redis-cli info | grep used_memory_human
```

### Check last time Redis cache was saved
```shell
redis-cli lastsave
```

### Check Redis cache memory usage
```shell
redis-cli info memory
```

### Check Redis cache AOF (Append Only File) size
```shell
redis-cli info persistence | grep aof
```

### Check Redis cache RDB (Redis Database File) size
```shell
redis-cli info persistence | grep rdb
```

## Repair

### Review the Redis cache configuration settings to ensure that it is set up for proper data expiration and eviction policies that match the data access patterns of the application.
```shell


#!/bin/bash



REDIS_CONFIG_FILE=${PATH_TO_REDIS_CONFIG_FILE}

REDIS_CACHE_EXPIRATION=${CACHE_EXPIRATION_TIME_IN_SECONDS}

REDIS_CACHE_EVICTION_POLICY=${CACHE_EVICTION_POLICY}



# Check if Redis config file exists

if [[ ! -f $REDIS_CONFIG_FILE ]]; then

  echo "Redis config file not found: $REDIS_CONFIG_FILE"

  exit 1

fi



# Update Redis cache expiration time and eviction policy

sed -i "s/^# *maxmemory-policy.*/maxmemory-policy $REDIS_CACHE_EVICTION_POLICY/g" $REDIS_CONFIG_FILE

sed -i "s/^# *expire.*/expire $REDIS_CACHE_EXPIRATION/g" $REDIS_CONFIG_FILE



# Restart Redis service

systemctl restart redis



echo "Redis cache configuration updated successfully"


```

Redis Cache Invalidation Incident refers to the situation where the Redis cache which is a key-value data store, fails to invalidate or remove data that has been modified or deleted in the primary data store. This can lead to inconsistencies and errors in the application that relies on the cache for faster data retrieval. The incident requires the identification of the root cause and the implementation of a solution to ensure that the cache stays in sync with the primary data store.


```shell
export CACHE_EXPIRATION_TIME_IN_SECONDS="PLACEHOLDER"

export PATH_TO_REDIS_CONFIG_FILE="PLACEHOLDER"

export CACHE_EVICTION_POLICY="PLACEHOLDER"
```


### Check Redis server is running

```shell
systemctl status redis-server
```

### Check connection to Redis server

```shell
redis-cli ping
```

### Check Redis keys

```shell
redis-cli keys *
```

### Check Redis cache size

```shell
redis-cli info | grep used_memory_human
```

### Check last time Redis cache was saved

```shell
redis-cli lastsave
```

### Check Redis cache memory usage

```shell
redis-cli info memory
```

### Check Redis cache AOF (Append Only File) size

```shell
redis-cli info persistence | grep aof
```

### Check Redis cache RDB (Redis Database File) size

```shell
redis-cli info persistence | grep rdb
```


### Review the Redis cache configuration settings to ensure that it is set up for proper data expiration and eviction policies that match the data access patterns of the application.

```shell


#!/bin/bash



REDIS_CONFIG_FILE=${PATH_TO_REDIS_CONFIG_FILE}

REDIS_CACHE_EXPIRATION=${CACHE_EXPIRATION_TIME_IN_SECONDS}

REDIS_CACHE_EVICTION_POLICY=${CACHE_EVICTION_POLICY}



# Check if Redis config file exists

if [[ ! -f $REDIS_CONFIG_FILE ]]; then

  echo "Redis config file not found: $REDIS_CONFIG_FILE"

  exit 1

fi



# Update Redis cache expiration time and eviction policy

sed -i "s/^# *maxmemory-policy.*/maxmemory-policy $REDIS_CACHE_EVICTION_POLICY/g" $REDIS_CONFIG_FILE

sed -i "s/^# *expire.*/expire $REDIS_CACHE_EXPIRATION/g" $REDIS_CONFIG_FILE



# Restart Redis service

systemctl restart redis



echo "Redis cache configuration updated successfully"


```


Redis Cache Invalidation Incident.

Overview

Parameters

Debug

Check Redis server is running

Check connection to Redis server

Check Redis keys

Check Redis cache size

Check last time Redis cache was saved

Check Redis cache memory usage

Check Redis cache AOF (Append Only File) size

Check Redis cache RDB (Redis Database File) size

Repair

Review the Redis cache configuration settings to ensure that it is set up for proper data expiration and eviction policies that match the data access patterns of the application.

Learn more

Related Runbooks

Support