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Add doc for temporary_data_in_cache

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docs/en/operations/server-configuration-parameters/settings.md
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@ -1539,33 +1539,103 @@ Example
<postgresql_port>9005</postgresql_port>
```
## tmp_path {#tmp-path}
Path to temporary data for processing large queries.
Path on the local filesystem to store temporary data for processing large queries.
:::note
The trailing slash is mandatory.
- Only one option can be used to configure temporary data storage: `tmp_path` ,`tmp_policy`, `temporary_data_in_cache`.
- The trailing slash is mandatory.
:::
**Example**
``` xml
```xml
<tmp_path>/var/lib/clickhouse/tmp/</tmp_path>
```
## tmp_policy {#tmp-policy}
Policy from [storage_configuration](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-multiple-volumes) to store temporary files.
If not set, [tmp_path](#tmp-path) is used, otherwise it is ignored.
Alternatively, a policy from [storage_configuration](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-multiple-volumes) can be used to store temporary files.
:::note
- `move_factor` is ignored.
- `keep_free_space_bytes` is ignored.
- `max_data_part_size_bytes` is ignored.
- Policy should have exactly one volume with local disks.
- Only one option can be used to configure temporary data storage: `tmp_path` ,`tmp_policy`, `temporary_data_in_cache`.
- `move_factor`, `keep_free_space_bytes`,`max_data_part_size_bytes` and are ignored.
- Policy should have exactly *one volume* with *local* disks.
:::
**Example**
```xml<clickhouse>
<storage_configuration>
<disks>
<disk1>
<path>/disk1/</path>
</disk1>
<disk2>
<path>/disk2/</path>
</disk2>
</disks>
<policies>
<tmp_two_disks>
<volumes>
<main>
<disk>disk1</disk>
<disk>disk2</disk>
</main>
</volumes>
</tmp_two_disks>
</policies>
</storage_configuration>
<tmp_policy>tmp_two_disks</tmp_policy>
</clickhouse>
```
When `/disk1` is full, temporary data will be stored on `/disk2`.
## temporary_data_in_cache {#temporary-data-in-cache}
With this option, temporary data will be stored in the cache for the particular disk.
In this section, you should specify the disk name with the type `cache`.
In that case, the cache and temporary data will share the same space, and the disk cache can be evicted to create temporary data.
:::note
- Only one option can be used to configure temporary data storage: `tmp_path` ,`tmp_policy`, `temporary_data_in_cache`.
:::
**Example**
```xml
<clickhouse>
<storage_configuration>
<disks>
<local_disk>
<type>local</type>
<path>/local_disk/</path>
</local_disk>
<tiny_local_cache>
<type>cache</type>
<disk>local_disk</disk>
<path>/tiny_local_cache/</path>
<max_size>10M</max_size>
<max_file_segment_size>1M</max_file_segment_size>
<cache_on_write_operations>1</cache_on_write_operations>
<do_not_evict_index_and_mark_files>0</do_not_evict_index_and_mark_files>
</tiny_local_cache>
</disks>
</storage_configuration>
<temporary_data_in_cache>tiny_local_cache</temporary_data_in_cache>
</clickhouse>
```
Cache for `local_disk` and temporary data will be stored in `/tiny_local_cache` on the filesystem, managed by `tiny_local_cache`.
## max_temporary_data_on_disk_size {#max_temporary_data_on_disk_size}
Limit the amount of disk space consumed by temporary files in `tmp_path` for the server.