5 Commits (d24fe3e68be4be16b3654e6aedafaa71ac9d307c)

Author	SHA1	Message	Date
Salva Corts	d24fe3e68b	Max bytes read limit (#8670) ... **What this PR does / why we need it**: This PR implements two new per-tenant limits that are enforced on log and metric queries (both range and instant) when TSDB is used: - `max_query_bytes_read`: Refuse queries that would read more than the configured bytes here. Overall limit regardless of splitting/sharding. The goal is to refuse queries that would take too long. The default value of 0 disables this limit. - `max_querier_bytes_read`: Refuse queries in which any of their subqueries after splitting and sharding would read more than the configured bytes here. The goal is to avoid a querier from running a query that would load too much data in memory and can potentially get OOMed. The default value of 0 disables this limit. These new limits can be configured per tenant and per query (see https://github.com/grafana/loki/pull/8727). The bytes a query would read are estimated through TSDB's index stats. Even though they are not exact, they are good enough to have a rough estimation of whether a query is too big to run or not. For more details on this refer to this discussion in the PR: https://github.com/grafana/loki/pull/8670#discussion_r1124858508. Both limits are implemented in the frontend. Even though we considered implementing `max_querier_bytes_read` in the querier, this way, the limits for pre and post splitting/sharding queries are enforced close to each other on the same component. Moreover, this way we can reduce the number of index stats requests issued to the index gateways by reusing the stats gathered while sharding the query. With regard to how index stats requests are issued: - We parallelize index stats requests by splitting them into queries that span up to 24h since our indices are sharded by 24h periods. On top of that, this prevents a single index gateway from processing a single huge request like `{app=~".+"} for 30d`. - If sharding is enabled and the query is shardable, for `max_querier_bytes_read`, we re-use the stats requests issued by the sharding ware. Specifically, we look at the [bytesPerShard][1] to enforce this limit. Note that once we merge this PR and enable these limits, the load of index stats requests will increase substantially and we may discover bottlenecks in our index gateways and TSDB. After speaking with @owen-d, we think it should be fine as, if needed, we can scale up our index gateways and support caching index stats requests. Here's a demo of this working: <img width="1647" alt="image" src="https://user-images.githubusercontent.com/8354290/226918478-d4b6c2fd-de4d-478a-9c8b-e38fe148fa95.png"> <img width="1647" alt="image" src="https://user-images.githubusercontent.com/8354290/226918798-a71b1db8-ea68-4d00-933b-e5eb1524d240.png"> **Which issue(s) this PR fixes**: This PR addresses https://github.com/grafana/loki-private/issues/674. **Special notes for your reviewer**: - @jeschkies has reviewed the changes related to query-time limits. - I've done some refactoring in this PR: - Extracted logic to get stats for a set of matches into a new function [getStatsForMatchers][2]. - Extracted the _Handler_ interface implementation for [queryrangebase.roundTripper][3] into a new type [queryrangebase.roundTripperHandler][4]. This is used to create the handler that skips the rest of configured middlewares when sending an index stat quests ([example][5]). **Checklist** - [x] Reviewed the [`CONTRIBUTING.md`](https://github.com/grafana/loki/blob/main/CONTRIBUTING.md) guide (**required**) - [x] Documentation added - [x] Tests updated - [x] `CHANGELOG.md` updated - [ ] Changes that require user attention or interaction to upgrade are documented in `docs/sources/upgrading/_index.md` [1]: ff847305af/pkg/querier/queryrange/shard_resolver.go (L179-L186) [2]: ff847305af/pkg/querier/queryrange/shard_resolver.go (L72) [3]: 3d2fff3a2d/pkg/querier/queryrange/queryrangebase/roundtrip.go (L124) [4]: 3d2fff3a2d/pkg/querier/queryrange/queryrangebase/roundtrip.go (L163) [5]: f422e0a52b/pkg/querier/queryrange/roundtrip.go (L521)	3 years ago
Owen Diehl	6a7403c4f5	correctly calculate max shards (#8494)	3 years ago
Owen Diehl	30db6c120e	[TSDB] 600MB max per shard in query planning (#7004) ... This PR gives a little better understanding into shard query planning and targets a range of `(300MB,600MB]` per shard. Doubling this also allows us to halve query parallelism configs and still schedule the same amount of work in parallel, which should make for easier schema upgrades as the parallelism differences between TSDB and prior period configs will be less. Co-authored-by: Dylan Guedes <djmgguedes@gmail.com>	3 years ago
Owen Diehl	094f8f3b20	[TSDB] fingerprint offsets is now correctly 16 byte aligned (#6630) ... * simpler shard factor calculations, disallows identity factor of 1 Signed-off-by: Owen Diehl <ow.diehl@gmail.com> * log interval span as soon as it finishes Signed-off-by: Owen Diehl <ow.diehl@gmail.com> * another shard bounds test Signed-off-by: Owen Diehl <ow.diehl@gmail.com> * indexclient span logging Signed-off-by: Owen Diehl <ow.diehl@gmail.com> * more index span logging Signed-off-by: Owen Diehl <ow.diehl@gmail.com> * correctly match single shard Signed-off-by: Owen Diehl <ow.diehl@gmail.com> * shardedPostings test Signed-off-by: Owen Diehl <ow.diehl@gmail.com> * shardedPostings maxOffset is properly exclusive Signed-off-by: Owen Diehl <ow.diehl@gmail.com> * minor posting idiomatic-ness Signed-off-by: Owen Diehl <ow.diehl@gmail.com> * store 16 byte aligned offsets for fingerprint table Signed-off-by: Owen Diehl <ow.diehl@gmail.com>	4 years ago
Owen Diehl	d6f50ca5e1	[TSDB] Use index sampling to determine shard factor (#6396) ... * use index sampling to determine shard factor * logging/tracing + better parallelism planning * queryrange downstreamer now checks max_query_parallelism * lint * handles interval, offset in tsdb planning and adds logging * fixes ns->ms confusion in index stats proto * handle zero shard value without panics * shardmapper will downstream a single unsharded query * uses concat expr with no shards to avoid query parsing errors * better logging * fixes wrong Size() method call and rounds to nearest KB when calculating chunk size * humanize bytes in log line * only adds defaultLookback to index sampling when interval is zero * removes comment * more logging * adjust through correctly * adds query length for index queries	4 years ago