perf(StringRedisTemplate): avoid redundant logger creation in execute().

[huangcanda]

Problem Description

Each invocation of StringRedisTemplate.execute() creates a new DefaultStringRedisConnection instance, resulting in repeated initialization of non-static logger instances. This causes redundant LogFactory lookups that ​consume an additional 10–15% CPU overhead.

Solution

Modify the private final Log logger field in DefaultStringRedisConnection to private static final Log logger.

Impact

10–15% reduction in CPU overhead for all Redis client command executions.

[christophstrobl]

Thanks for the heads up. There are a couple of other places in the codebase as well that would benefit from this kind of change. Would you like have a look and extend the PR to those, or should we take care of the rest.

[huangcanda]

Sure, I’d be happy to extend the PR.

However, since my initial change was based on a specific performance issue I encountered, I haven’t done a full review of the codebase.

If you could point me to the places you think would benefit from similar optimizations, I’ll gladly take a look and update the PR accordingly.

[christophstrobl]

great - thank you!
I think we should also change the following: DefaultStreamReceiver, JedisClusterConnection, JedisConnection, JedisConnectionFactory, LettuceClusterConnection, LettuceConnection, LettuceConnectionFactory, RedisAccessor, RedisKeyValueAdapter, RedisMessageListenerContainer, MessageListenerAdapter

[huangcanda]

I've updated the PR based on your suggestions. Please review when convenient. Thanks!