Redis
Table of contents
Find keys given a pattern
The SCAN command can be safely used in production. This may be a little slow (few hundred per second), but may be sufficient depending on how many keys you’re expecting to find.
redis-cli has command line flags to automatically iterate through the SCAN
results. The -i flag can be passed to throttle the SCAN commands, reducing
CPU usage on the server.
redis-cli -i 0.01 --scan --pattern 'user:*'
An alternative is to use redis-rdb-tools, if you have access to the RDB dump.
rdb --command justkeys --key "user:.*"
With redis-rdb-tools, you can create custom filters, for instance to find all non-expiring keys.
Latency spikes during RDB snapshots
The latency spikes may be caused by Transparent Huge Pages (THP) being enabled, which is typically the default. This setting should be disabled for Redis instances.
Other resources about THPs: