Update description of MAX_WRITE_SPEED
#20852
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Hello @joechenrh, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!
Summary of Changes
This pull request updates the description of the MAX_WRITE_SPEED parameter in the sql-statement-import-into.md file. The change clarifies that the write speed control applies to each TiDB node writing to TiKV, rather than to a single TiKV node.
Highlights
- Documentation Update: The description of
MAX_WRITE_SPEEDis updated to specify that it controls the write speed of each TiDB node to TiKV. - Clarification: The change clarifies the scope of the
MAX_WRITE_SPEEDparameter, making it more precise.
Changelog
- sql-statements/sql-statement-import-into.md
- Updated the description of
MAX_WRITE_SPEEDto clarify that it controls the write speed of each TiDB node to TiKV.
- Updated the description of
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Code Review
The pull request updates the description of the MAX_WRITE_SPEED parameter in the IMPORT INTO documentation. The change clarifies that the write speed control applies to each TiDB node writing to TiKV. This is a small but important clarification for users configuring this parameter.
Merge Readiness
The pull request provides a valuable clarification to the documentation. There are no identified issues that would block merging. However, it's important to ensure the change aligns with the actual behavior of the MAX_WRITE_SPEED parameter. I am unable to approve this pull request, and recommend that others review and approve this code before merging.
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[APPROVALNOTIFIER] This PR is NOT APPROVED This pull-request has been approved by: The full list of commands accepted by this bot can be found here.
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| @@ -280,7 +280,7 @@ The `security` section specifies certificates and keys for TLS connections withi | |||
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| #### `store-write-bwlimit` | |||
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| - Limits the bandwidth in which TiDB Lightning writes data into each TiKV node in the physical import mode. | |||
| - Limits the per-table bandwidth to write data into TiKV for each TiDB Lightning instance in the physical import mode. | |||
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i remember all tables in one lightning instance shares the same limit
| @@ -151,7 +151,7 @@ The supported options are described as follows: | |||
| | `DISK_QUOTA='<string>'` | All file formats | Specifies the disk space threshold that can be used during data sorting. The default value is 80% of the disk space in the TiDB [temporary directory](https://docs.pingcap.com/tidb/stable/tidb-configuration-file#temp-dir-new-in-v630). If the total disk size cannot be obtained, the default value is 50 GiB. When specifying `DISK_QUOTA` explicitly, make sure that the value does not exceed 80% of the disk space in the TiDB temporary directory. | | |||
| | `DISABLE_TIKV_IMPORT_MODE` | All file formats | Specifies whether to disable switching TiKV to import mode during the import process. By default, switching TiKV to import mode is not disabled. If there are ongoing read-write operations in the cluster, you can enable this option to avoid impact from the import process. | | |||
| | `THREAD=<number>` | All file formats and query results of `SELECT` | Specifies the concurrency for import. For `IMPORT INTO ... FROM FILE`, the default value of `THREAD` is 50% of the number of CPU cores on the TiDB node, the minimum value is `1`, and the maximum value is the number of CPU cores. For `IMPORT INTO ... FROM SELECT`, the default value of `THREAD` is `2`, the minimum value is `1`, and the maximum value is two times the number of CPU cores on the TiDB node. To import data into a new cluster without any data, it is recommended to increase this concurrency appropriately to improve import performance. If the target cluster is already used in a production environment, it is recommended to adjust this concurrency according to your application requirements. | | |||
| | `MAX_WRITE_SPEED='<string>'` | All file formats | Controls the write speed to a TiKV node. By default, there is no speed limit. For example, you can specify this option as `1MiB` to limit the write speed to 1 MiB/s. | | |||
| | `MAX_WRITE_SPEED='<string>'` | All file formats | Controls the write speed of each TiDB node to TiKV. By default, there is no speed limit. For example, if you have 10 TiDB nodes, specifying this option as `1MiB` limits the total write speed to 10 MiB/s. | | |||
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| | `MAX_WRITE_SPEED='<string>'` | All file formats | Controls the write speed of each TiDB node to TiKV. By default, there is no speed limit. For example, if you have 10 TiDB nodes, specifying this option as `1MiB` limits the total write speed to 10 MiB/s. | | |
| | `MAX_WRITE_SPEED='<string>'` | All file formats | Controls the write speed of each TiDB node to TiKV. By default, there is no speed limit. For example, if you have 10 TiDB nodes, specifying this option as `1MiB` limits the total write speed to some TiKV to be 10 MiB/s. | |
| - The default value `0` means no write bandwidth limit. | ||
| - You can specify the value of this variable either with a unit or without a unit. | ||
| - When you specify the value without a unit, the default unit is bytes per second. For example, `67108864` represents `64MiB` per second. | ||
| - When you specify the value with a unit, supported units include KiB, MiB, GiB, and TiB. For example, `'1GiB`' represents 1 GiB per second, and `'256MiB'` represents 256 MiB per second. | ||
| - When the Distributed eXecution Framework (DXF) is enabled, this write limit applies to each TiDB node respectively. For example, if you add index using 4 TiDB nodes, setting this variable to `64MiB` means the maximum write speed to TiKV is `256MiB/s`. |
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| - When the Distributed eXecution Framework (DXF) is enabled, this write limit applies to each TiDB node respectively. For example, if you add index using 4 TiDB nodes, setting this variable to `64MiB` means the maximum write speed to TiKV is `256MiB/s`. | |
| - When the Distributed eXecution Framework (DXF) is enabled, this write limit applies to each TiDB node respectively. For example, if you add index using 4 TiDB nodes, setting this variable to `64MiB` means the maximum write speed to one TiKV node is `256MiB/s`. |
| @@ -280,7 +280,7 @@ The `security` section specifies certificates and keys for TLS connections withi | |||
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| #### `store-write-bwlimit` | |||
|
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| - Limits the bandwidth in which TiDB Lightning writes data into each TiKV node in the physical import mode. | |||
| - Limits the per-table bandwidth to write data into TiKV for each TiDB Lightning instance in the physical import mode. | |||
There was a problem hiding this comment.
i remember all tables in one lightning instance shares the same limit
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