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Virtual column in Distributed updated, link fixed, links added

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Alexey 2021-10-09 19:17:02 +00:00
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8
docs/en/engines/table-engines/special/distributed.md
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@ -188,15 +188,15 @@ When the `max_parallel_replicas` option is enabled, query processing is parallel
## Virtual Columns {#virtual-columns}
- `_shard_num` — Contains the `shard_num` (from `system.clusters`). Type: [UInt32](../../../sql-reference/data-types/int-uint.md).
- `_shard_num` — Contains the `shard_num` value from the table `system.clusters`. Type: [UInt32](../../../sql-reference/data-types/int-uint.md).
!!! note "Note"
Since [`remote`](../../../sql-reference/table-functions/remote.md)/`cluster` table functions internally create temporary instance of the same Distributed engine, `_shard_num` is available there too.
Since [remote](../../../sql-reference/table-functions/remote.md) and [cluster](../../../sql-reference/table-functions/cluster.md) table functions internally create temporary Distributed table, `_shard_num` is available there too.
**See Also**
- [Virtual columns](../../../engines/table-engines/special/index.md#table_engines-virtual_columns)
- [background_distributed_schedule_pool_size](../../../operations/settings/settings.md#background_distributed_schedule_pool_size)
- [Virtual columns](../../../engines/table-engines/index.md#table_engines-virtual_columns) description
- [background_distributed_schedule_pool_size](../../../operations/settings/settings.md#background_distributed_schedule_pool_size) setting
- [shardNum()](../../../sql-reference/functions/other-functions.md#shard-num) and [shardCount()](../../../sql-reference/functions/other-functions.md#shard-count) functions

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docs/ru/engines/table-engines/special/distributed.md
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@ -136,3 +136,15 @@ logs - имя кластера в конфигурационном файле с
При выставлении опции max_parallel_replicas выполнение запроса распараллеливается по всем репликам внутри одного шарда. Подробнее смотрите раздел [max_parallel_replicas](../../../operations/settings/settings.md#settings-max_parallel_replicas).
## Виртуальные столбцы {#virtual-columns}
- `_shard_num` — содержит значение `shard_num` из таблицы `system.clusters`. Тип: [UInt32](../../../sql-reference/data-types/int-uint.md).
!!! note "Примечание"
Так как табличные функции [remote](../../../sql-reference/table-functions/remote.md) и [cluster](../../../sql-reference/table-functions/cluster.md) создают временную таблицу на движке `Distributed`, то в ней также доступен столбец `_shard_num`.
**Смотрите также**
- общее описание [виртуальных столбцов](../../../engines/table-engines/index.md#table_engines-virtual_columns)
- настройка [background_distributed_schedule_pool_size](../../../operations/settings/settings.md#background_distributed_schedule_pool_size)
- функции [shardNum()](../../../sql-reference/functions/other-functions.md#shard-num) и [shardCount()](../../../sql-reference/functions/other-functions.md#shard-count)