redis "10000 changes in 60 seconds" is running only every 3 minutes

Question

I'm investigating redis memory issues on our system.

I'm trying to figure out what are the 10000 changes that are made (it is too many in my opinion)

The weird thing is that I'm getting 10000 changes in 60 seconds. Saving... but every 3 minutes and not 60 seconds as I would have expected.

Log sample:

[10993] 03 Jan 06:37:46.166 * 10000 changes in 60 seconds. Saving...
[10993] 03 Jan 06:37:46.167 * Background saving started by pid 4802
[4802] 03 Jan 06:37:46.170 * DB saved on disk
[4802] 03 Jan 06:37:46.170 * RDB: 2 MB of memory used by copy-on-write
[10993] 03 Jan 06:37:46.268 * Background saving terminated with success
[10993] 03 Jan 06:40:27.140 * 10000 changes in 60 seconds. Saving...
[10993] 03 Jan 06:40:27.141 * Background saving started by pid 5081
[5081] 03 Jan 06:40:27.145 * DB saved on disk
[5081] 03 Jan 06:40:27.145 * RDB: 2 MB of memory used by copy-on-write
[10993] 03 Jan 06:40:27.242 * Background saving terminated with success
[10993] 03 Jan 06:43:08.335 * 10000 changes in 60 seconds. Saving...

redis_version:2.8.4

Answer 1

save 60 10000 in your config means that redis periodically checks if there has been at least 10000 changes and its been at least 60 seconds since the last rdb save. Only when both of these conditions are met (for any of your save points) does a new rdb save start.

Also, if you think 10000 changes in ~3min sounds like a lot, don't forget that one command can increase the change count by more than one, e.g. MSET.