Database > EasyCache > Developer Guide

Client Access

EasyCache can be accessed from applications in instances using the same VPC subnet. Since EasyCache is based on Redis, it supports various development programming languages.

JAVA

Jedis is a Redis client for JAVA.

The following is the JAR files required for installation. * jedis-2.9.0.jar * commons-pool2-2.4.2.jar

Code Example for Access

 public static void main( String[] args ) {
    Jedis jedis = new Jedis("localhost", 6379);
    jedis.set("foo", "bar");
}

PHP

Predis is a Redis client for PHP.

Code Example for Access

$client = new Predis\Client('tcp://127.0.0.1:6379');
$client->set('hogehoge','fugafuga');

Or

$client = new Predis\Client([
    'scheme' => 'tcp',
    'host'   => '192.168.10.33',
    'port'   => 6379,
]);
$client->set('hogehoge','fugafuga');

Python

redis-py is a Redis client for Python. redis-py can be installed as follows.

$ pip install redis

Code Example for Access

import redis

r = r = redis.StrictRedis(host='localhost', port=6379, db=0)
r.set('hoge', 'moge')

Or

import redis

pool = redis.ConnectionPool(host='localhost', port=6379, db=0)
r = redis.StrictRedis(connection_pool=pool)
r.set('hoge', 'moge')

Access EasyCache for Redis Server from an Instance

A Redis server can be accessed only from within the same VPC subnet. Create an instance in the same VPC subnet.

To use a Redis client, you must install Redis for each OS.

For CentOS:
yum -y install epel-release
yum -y install redis

When the installation is finished, check that it is installed properly.

redis-cli -v

Select the replication group to access and click the Access Information tab in the details. rep_de_005.PNG

  • Select the one between private and public commands and click the Copy button to copy the command. Paste the copied command on the instance's command window.
  • Connect to the Redis server.
  • When you click Show button on the password, the password is displayed and the Copy button is enabled.
  • Click the Copy button to copy the password.
  • Authenticate using the AUTH command.
    • AUTH {copied password}

Redis Command Restriction

Use of the following commands is restricted as it may have a fatal impact on the service.

  • BGREWRITEAOF
  • BGSAVE
  • CONFIG
  • DEBUG
  • MIGRATE
  • SAVE
  • SHUTDOWN
  • SLAVEOF
  • REPLICAOF
  • SYNC

When the number of key or item is large (more than hundreds of thousands), the performance may decrease or the system may hang if the following commands are used.

  • KEYS
  • FLUSHALL, FLUSHDB
  • Delete Collections
  • Get All Collections

Memory Management

If the system memory usage exceeds 80%, you must do the following to prevent out-of-memory situation on your instance.

  • You should monitor the memory usage. Learn about the EasyCache alarm function.
  • Enable activedefrag on the instance.
  • You should lower the maxmemory limit of the instance.
  • Choose an appropriate maxmemory-policy
    • If you are storing volatile data, choose one of the volatile- eviction policies. If you are storing non-volatile data, choose one of the allkeys- policies.
  • Follow the instance scaling instructions to increase instance capacity.
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