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* 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 |
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| .. | ||
| tests | ||
| CMakeLists.txt | ||
| Connection.cpp | ||
| Connection.h | ||
| ConnectionPool.h | ||
| ConnectionPoolWithFailover.cpp | ||
| ConnectionPoolWithFailover.h | ||
| MultiplexedConnections.cpp | ||
| MultiplexedConnections.h | ||
| TimeoutSetter.cpp | ||
| TimeoutSetter.h | ||
| ya.make | ||
| ya.make.in | ||