Receive: Dont rebatch already replicated requests

[matej-g]

• I added CHANGELOG entry for this change.
• Change is not relevant to the end user.

Changes

Part of #5807.

Since change in #5604, we are already hashing each time series by endpoint and replica, meaning that replicated requests will now always be sent to the actual endpoint to which they are supposed to be written. This means the 're-batching' of series upon receiving a replicated request is redundant and can be skipped.

Verification

Tests are succeeding locally. I also added one more benchmark with replicated request to see changes:

name                                                                                   old time/op    new time/op    delta
HandlerReceiveHTTP/typical_labels_under_1KB,_500_of_them/OK-12                           1.00ms ± 7%    0.97ms ± 8%     ~     (p=0.123 n=10+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_500_of_them/OK-with-replicated-12            992µs ± 7%     817µs ± 6%  -17.60%  (p=0.000 n=10+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_500_of_them/conflict_errors-12              1.15ms ±10%    1.14ms ± 7%     ~     (p=0.684 n=10+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_5000_of_them/OK-12                          10.2ms ± 6%    10.0ms ±16%     ~     (p=0.165 n=10+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_5000_of_them/OK-with-replicated-12          10.2ms ± 5%     8.0ms ± 6%  -21.21%  (p=0.000 n=10+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_5000_of_them/conflict_errors-12             12.1ms ± 7%    11.7ms ± 3%     ~     (p=0.146 n=10+8)
HandlerReceiveHTTP/typical_labels_under_1KB,_20000_of_them/OK-12                         41.3ms ± 4%    41.2ms ±11%     ~     (p=0.243 n=9+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_20000_of_them/OK-with-replicated-12         41.4ms ± 6%    34.2ms ±10%  -17.22%  (p=0.000 n=10+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_20000_of_them/conflict_errors-12            48.3ms ±11%    48.5ms ± 9%     ~     (p=0.739 n=10+10)
HandlerReceiveHTTP/extremely_large_label_value_10MB,_10_of_them/OK-12                    81.7ms ± 3%    85.8ms ±11%     ~     (p=0.203 n=8+10)
HandlerReceiveHTTP/extremely_large_label_value_10MB,_10_of_them/OK-with-replicated-12    87.8ms ±16%    76.5ms ±18%  -12.88%  (p=0.001 n=10+10)
HandlerReceiveHTTP/extremely_large_label_value_10MB,_10_of_them/conflict_errors-12       89.4ms ±13%    87.0ms ±10%     ~     (p=0.529 n=10+10)

name                                                                                   old alloc/op   new alloc/op   delta
HandlerReceiveHTTP/typical_labels_under_1KB,_500_of_them/OK-12                           1.15MB ± 0%    1.15MB ± 0%     ~     (p=0.661 n=10+9)
HandlerReceiveHTTP/typical_labels_under_1KB,_500_of_them/OK-with-replicated-12           1.15MB ± 0%    1.07MB ± 0%   -6.98%  (p=0.000 n=9+9)
HandlerReceiveHTTP/typical_labels_under_1KB,_500_of_them/conflict_errors-12              1.41MB ± 0%    1.41MB ± 0%     ~     (p=0.781 n=10+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_5000_of_them/OK-12                          13.1MB ± 0%    13.1MB ± 0%     ~     (p=0.190 n=10+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_5000_of_them/OK-with-replicated-12          13.1MB ± 0%    11.5MB ± 0%  -12.27%  (p=0.000 n=10+9)
HandlerReceiveHTTP/typical_labels_under_1KB,_5000_of_them/conflict_errors-12             15.5MB ± 0%    15.5MB ± 0%     ~     (p=0.315 n=10+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_20000_of_them/OK-12                         52.6MB ± 1%    52.8MB ± 1%     ~     (p=0.190 n=9+9)
HandlerReceiveHTTP/typical_labels_under_1KB,_20000_of_them/OK-with-replicated-12         52.9MB ± 2%    46.4MB ± 1%  -12.23%  (p=0.000 n=10+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_20000_of_them/conflict_errors-12            62.0MB ± 0%    62.0MB ± 0%     ~     (p=0.063 n=10+10)
HandlerReceiveHTTP/extremely_large_label_value_10MB,_10_of_them/OK-12                     110MB ± 0%     110MB ± 0%     ~     (p=0.950 n=9+10)
HandlerReceiveHTTP/extremely_large_label_value_10MB,_10_of_them/OK-with-replicated-12     110MB ± 0%     110MB ± 0%     ~     (p=0.982 n=9+9)
HandlerReceiveHTTP/extremely_large_label_value_10MB,_10_of_them/conflict_errors-12        110MB ± 0%     110MB ± 0%     ~     (p=0.072 n=10+10)

name                                                                                   old allocs/op  new allocs/op  delta
HandlerReceiveHTTP/typical_labels_under_1KB,_500_of_them/OK-12                            3.10k ± 0%     3.10k ± 0%     ~     (all equal)
HandlerReceiveHTTP/typical_labels_under_1KB,_500_of_them/OK-with-replicated-12            3.10k ± 0%     3.09k ± 0%   -0.35%  (p=0.000 n=10+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_500_of_them/conflict_errors-12               6.63k ± 0%     6.63k ± 0%     ~     (p=0.650 n=10+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_5000_of_them/OK-12                           30.3k ± 0%     30.3k ± 0%     ~     (p=0.423 n=10+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_5000_of_them/OK-with-replicated-12           30.3k ± 0%     30.3k ± 0%   -0.06%  (p=0.000 n=10+9)
HandlerReceiveHTTP/typical_labels_under_1KB,_5000_of_them/conflict_errors-12              65.1k ± 0%     65.1k ± 0%     ~     (p=1.000 n=10+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_20000_of_them/OK-12                           121k ± 0%      121k ± 0%     ~     (p=0.763 n=10+9)
HandlerReceiveHTTP/typical_labels_under_1KB,_20000_of_them/OK-with-replicated-12           121k ± 0%      121k ± 0%   -0.02%  (p=0.000 n=10+10)
HandlerReceiveHTTP/typical_labels_under_1KB,_20000_of_them/conflict_errors-12              260k ± 0%      260k ± 0%     ~     (p=0.064 n=10+10)
HandlerReceiveHTTP/extremely_large_label_value_10MB,_10_of_them/OK-12                      88.8 ± 2%      87.7 ± 1%     ~     (p=0.154 n=10+10)
HandlerReceiveHTTP/extremely_large_label_value_10MB,_10_of_them/OK-with-replicated-12      89.7 ± 2%      84.3 ± 4%   -5.99%  (p=0.000 n=9+10)
HandlerReceiveHTTP/extremely_large_label_value_10MB,_10_of_them/conflict_errors-12          218 ± 1%       219 ± 1%   +0.61%  (p=0.042 n=9+9)

Note

We should make obvious to our users that this change is not fully compatible between older and newer versions of receive. In particular if any user would be running a mix of pre-0.28.0 receivers and receivers with this change (which can happen during a rollout), the batching would not work correctly. It is therefore important to instruct users to first update their receivers to version to either 0.28.0 or 0.29.0 and only then to newer version with this change.

[fpetkovski]

👍

[fpetkovski]

Hopefully in the long term we can end up with your idea of calculating all replicas for all batches in one place, but this should be good enough for now.

[jessicalins]

LGTM :)

[saswatamcode]

LGTM!

[saswatamcode]

Can this be rebased? 🙂

[matej-g]

Closing as this has been superseded by #5910