Reduce the cache entry expiration TTL #1481
Conversation
| @@ -242,7 +242,7 @@ | |||
| # https://docs.pulpproject.org/pulpcore/configuration/settings.html#pulp-cache | |||
| CACHE_ENABLED = True | |||
| CACHE_SETTINGS = { | |||
| "EXPIRES_TTL": 86400, | |||
pulpcore/app/settings.py
Outdated
| @@ -242,7 +242,7 @@ | |||
| # https://docs.pulpproject.org/pulpcore/configuration/settings.html#pulp-cache | |||
| CACHE_ENABLED = True | |||
| CACHE_SETTINGS = { | |||
| "EXPIRES_TTL": 86400, | |||
| "EXPIRES_TTL": 480, # 8 minutes | |||
There was a problem hiding this comment.
According to @jlsherrill , most large users would have their clusters updating over a fairly short timeframe, so an expiration time measured in minutes is reasonable and would still result in high utilization.
We want to reduce the impact / risk of any significant cache-invalidation events. (e.g. Redis goes down, Pulp keeps going and invalidates cache, Redis comes back)
The ideal amount of time is up for debate though, and perhaps we should consider adding a little bit of randomness to amortize the cost of cache expiration events.
|
Attached issue: https://pulp.plan.io/issues/8996 |
| @@ -0,0 +1 @@ | |||
| Reduced the default expiration TTL of entries in the Pulp content app cache. | |||
There was a problem hiding this comment.
I feel like this is maybe worth exposing to users.
There was a problem hiding this comment.
We never advertised the default to begin with so I don't really think it's necessary. However I've just added it to the configuration docs.
If Redis goes down then its persisted data can get out of sync with Pulp, because cache invalidation events cannot occur. We should mitigate the impact by letting cache entries expire after a shorter period of time. closes: #8996 https://pulp.plan.io/issues/8996
dralley
force-pushed
the
cache-expiration
branch
from
6645d7a
to
9f5d494
Compare
If Redis goes down then its persisted data can get out of sync with
Pulp, because cache invalidation events cannot occur. We should mitigate
the impact by letting cache entries expire after a shorter period of
time.
closes: #8996
https://pulp.plan.io/issues/8996