Node Redis Get Slow Log (Detailed Guide w/ Code Examples)

Use Case(s)

In Node.js, Redis 'SLOWLOG' command is used to interact with the Redis slow queries log. It can be useful for debugging performance issues.

Code Examples

Example 1: Retrieving the entire slow log

In this example, we use the slowlog method of a redis client to get the entire slow log.

const redis = require('redis');
const client = redis.createClient();

client.slowlog('get', (err, logEntries) => {
    if (err) throw err;
    console.log(logEntries);
});

Example 2: Adjusting the length of the slow log

In this example, we set the length of the slow log to a specific number using slowlog and 'config' commands.

const redis = require('redis');
const client = redis.createClient();

client.config('set', 'slowlog-log-slower-than', 10000, (err) => {
    if (err) throw err;
});

client.slowlog('get', 10, (err, logEntries) => {
    if (err) throw err;
    console.log(logEntries);
});

Best Practices

It's best not to leave the slow log turned on indefinitely or set it to a very high limit, as this might consume much memory.

Common Mistakes

Not handling errors properly when they occur during interacting with the slow log. Always ensure you have an error callback that can handle any potential errors.

FAQs

Q: Is there a way to reset the slow log in Redis? A: Yes, you can use the slowlog('reset') command to clear the slow log. E.g.,

client.slowlog('reset', (err) => {
  if (err) throw err;
});