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Merge pull request #34321 from gauravphoenix/patch-2

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reference to  distributed queries processing
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Maksim Kita 2022-02-13 16:01:28 +01:00 committed by GitHub
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docs/en/engines/table-engines/special/distributed.md
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@ -209,6 +209,8 @@ When querying a `Distributed` table, `SELECT` queries are sent to all shards and
When the `max_parallel_replicas` option is enabled, query processing is parallelized across all replicas within a single shard. For more information, see the section [max_parallel_replicas](../../../operations/settings/settings.md#settings-max_parallel_replicas).
To learn more about how distibuted `in` and `global in` queries are processed, refer to [this](../../../sql-reference/operators/in.md#select-distributed-subqueries) documentation.
## Virtual Columns {#virtual-columns}
- `_shard_num` — Contains the `shard_num` value from the table `system.clusters`. Type: [UInt32](../../../sql-reference/data-types/int-uint.md).