Redis获取连接池失败的原因剖析

今天打开网页提示服务器异常，查看服务器的log，发现了异常：

Caused by: redis.clients.jedis.exceptions.JedisException: Could not get a resource from the pool
    at redis.clients.util.Pool.getResource(Pool.java:51) ~[jedis-2.9.0.jar:?]
    at redis.clients.jedis.JedisPool.getResource(JedisPool.java:226) ~[jedis-2.9.0.jar:?]
    at redis.clients.jedis.JedisPool.getResource(JedisPool.java:16) ~[jedis-2.9.0.jar:?]
    at org.springframework.data.redis.connection.jedis.JedisConnectionFactory.fetchJedisConnector(JedisConnectionFactory.java:194) ~[spring-data-redis-1.8.6.RELEASE.jar:?]
    ... 85 more
Caused by: java.util.NoSuchElementException: Unable to validate object
    at org.apache.commons.pool2.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:506) ~[commons-pool2-2.4.2.jar:2.4.2]
    at org.apache.commons.pool2.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:363) ~[commons-pool2-2.4.2.jar:2.4.2]
    at redis.clients.util.Pool.getResource(Pool.java:49) ~[jedis-2.9.0.jar:?]
    at redis.clients.jedis.JedisPool.getResource(JedisPool.java:226) ~[jedis-2.9.0.jar:?]
    at redis.clients.jedis.JedisPool.getResource(JedisPool.java:16) ~[jedis-2.9.0.jar:?]
    at org.springframework.data.redis.connection.jedis.JedisConnectionFactory.fetchJedisConnector(JedisConnectionFactory.java:194) ~[spring-data-redis-1.8.6.RELEASE.jar:?]
    ... 85 more

大意就是获取连接池失败，在linux的terminal输入命令确保redis server开启：

image.png

输入命令redis-cli开启redis客户端，测试ping一下，发现错误；尝试插入一个值set test hello，一样的错误：

image.png
大意为：（错误）misconf redis被配置以保存数据库快照，但misconf redis目前不能在硬盘上持久化。用来修改数据集合的命令不能用，请使用日志的错误详细信息。

这是由于强制停止redis快照，不能持久化引起的。

运行info命令查看redis快照的状态，如下:

image.png

解决方案如下：

运行config set stop-writes-on-bgsave-error no命令关闭配置项stop-writes-on-bgsave-error解决该问题。