# Which Problems Are Solved
Cached object may have a different schema between Zitadel versions.
# How the Problems Are Solved
Use the curent build version in DB based cache connectors PostgreSQL and
Redis.
# Additional Changes
- Cleanup the ZitadelVersion field from the authz Instance
- Solve potential race condition on global variables in build package.
# Additional Context
- Closes https://github.com/zitadel/zitadel/issues/10648
- Obsoletes https://github.com/zitadel/zitadel/pull/10646
- Needs to be back-ported to v4 over
https://github.com/zitadel/zitadel/pull/10645
(cherry picked from commit f6f37d3a31)
# Which Problems Are Solved
If a redis cache has connection issues or any other type of permament
error,
it tanks the responsiveness of ZITADEL.
We currently do not support things like Redis cluster or sentinel. So
adding a simple redis cache improves performance but introduces a single
point of failure.
# How the Problems Are Solved
Implement a [circuit
breaker](https://learn.microsoft.com/en-us/previous-versions/msp-n-p/dn589784(v=pandp.10)?redirectedfrom=MSDN)
as
[`redis.Limiter`](https://pkg.go.dev/github.com/redis/go-redis/v9#Limiter)
by wrapping sony's [gobreaker](https://github.com/sony/gobreaker)
package. This package is picked as it seems well maintained and we
already use their `sonyflake` package
# Additional Changes
- The unit tests constructed an unused `redis.Client` and didn't cleanup
the connector. This is now fixed.
# Additional Context
Closes#8864
# Which Problems Are Solved
Add a cache implementation using Redis single mode. This does not add
support for Redis Cluster or sentinel.
# How the Problems Are Solved
Added the `internal/cache/redis` package. All operations occur
atomically, including setting of secondary indexes, using LUA scripts
where needed.
The [`miniredis`](https://github.com/alicebob/miniredis) package is used
to run unit tests.
# Additional Changes
- Move connector code to `internal/cache/connector/...` and remove
duplicate code from `query` and `command` packages.
- Fix a missed invalidation on the restrictions projection
# Additional Context
Closes#8130
