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Diffstat (limited to 'doc/development/redis.md')
| -rw-r--r-- | doc/development/redis.md | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/doc/development/redis.md b/doc/development/redis.md index ebc7c0271a1..19a6b8e75d4 100644 --- a/doc/development/redis.md +++ b/doc/development/redis.md @@ -56,7 +56,7 @@ the entry, instead of relying on the key changing. ### Multi-key commands -GitLab supports Redis Cluster only for the Redis [rate-limiting](https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/redis/rate_limiting.rb) type, introduced in [epic 823](https://gitlab.com/groups/gitlab-com/gl-infra/-/epics/823). +GitLab supports Redis Cluster for [cache-related workloads](https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/redis/cache.rb) type, introduced in [epic 878](https://gitlab.com/groups/gitlab-com/gl-infra/-/epics/878). This imposes an additional constraint on naming: where GitLab is performing operations that require several keys to be held on the same Redis server - for @@ -81,6 +81,12 @@ Developers are highly encouraged to use [hash-tags](https://redis.io/docs/refere where appropriate to facilitate future adoption of Redis Cluster in more Redis types. For example, the Namespace model uses hash-tags for its [config cache keys](https://gitlab.com/gitlab-org/gitlab/-/blob/1a12337058f260d38405886d82da5e8bb5d8da0b/app/models/namespace.rb#L786). +To perform multi-key commands, developers may use the [`Gitlab::Redis::CrossSlot::Pipeline`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/redis/cross_slot.rb) wrapper. +However, this does not work for [transactions](https://redis.io/docs/interact/transactions/) as Redis Cluster does not support cross-slot transactions. + +For `Rails.cache`, we handle the `MGET` command found in `read_multi_get` by [patching it](https://gitlab.com/gitlab-org/gitlab/-/blob/c2bad2aac25e2f2778897bd4759506a72b118b15/lib/gitlab/patch/redis_cache_store.rb#L10) to use the `Gitlab::Redis::CrossSlot::Pipeline` wrapper. +The minimum size of the pipeline is set to 1000 commands and it can be adjusted by using the `GITLAB_REDIS_CLUSTER_PIPELINE_BATCH_LIMIT` environment variable. + ## Redis in structured logging For GitLab Team Members: There are <i class="fa fa-youtube-play youtube" aria-hidden="true"></i> |