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a0488d21d2
ClickHouse
/
tests
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integration
/
test_query_deduplication
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configs
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deduplication_settings.xml
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Change <yandex> to <clickhouse> in configs
2021-09-19 22:38:53 +00:00
<clickhouse
>
CLICKHOUSE-606: query deduplication based on parts' UUID * add the query data deduplication excluding duplicated parts in MergeTree family engines. query deduplication is based on parts' UUID which should be enabled first with merge_tree setting assign_part_uuids=1 allow_experimental_query_deduplication setting is to enable part deduplication, default ot false. data part UUID is a mechanism of giving a data part a unique identifier. Having UUID and deduplication mechanism provides a potential of moving parts between shards preserving data consistency on a read path: duplicated UUIDs will cause root executor to retry query against on of the replica explicitly asking to exclude encountered duplicated fingerprints during a distributed query execution. NOTE: this implementation don't provide any knobs to lock part and hence its UUID. Any mutations/merge will update part's UUID. * add _part_uuid virtual column, allowing to use UUIDs in predicates. Signed-off-by: Aleksei Semiglazov <asemiglazov@cloudflare.com> address comments
2020-11-20 17:23:53 +00:00
<merge_tree
>
<assign_part_uuids
>
1
</assign_part_uuids>
</merge_tree>
Change <yandex> to <clickhouse> in configs
2021-09-19 22:38:53 +00:00
</clickhouse>
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