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237184324e
"
Since f8613a8415 we have reader-caching
on replicas for single-partition queries. This caching works best when
all pages of a query are sent to the same replicas consistently and thus
they can reuse the cached readers there.
The propability-based nature of read-repair works against this as on any
given page a read-repair will be attempted or not based on probability.
This will cause hight drop-rates on the replicas used for read-repair as
the cached reader will not be reusable if the replica was skipped for
one or more pages.
To fix this make the repair-decision once, on the first page of the
query and store the decision in the paging-state. On all remaining
pages of the query use this stored decision.
Tests: unit-tests(release, debug), dtest(paging_advanced_tests.py)
Refs: #1865
"
* 'per_query_repair_decision/v2' of https://github.com/denesb/scylla:
Make the read-repair decision only once
storage_proxy: add coordinator_query_options and coordinator_query_result
Add query_read_repair_decision to paging-state