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This PR fixes several TiDB Lightning documentation inconsistencies in the SQL, CSV, and Parquet import guides and aligns the shared Lightning references:
remove quotes around tidb.port and tidb.status-port placeholders in the import-guide TOML examples so they match the documented integer configuration types
clarify in the SQL import guide that Lightning only auto-detects SQL data files that follow the default filename patterns, unless [[mydumper.files]] is configured
update the strict-format examples to include the required non-empty mydumper.csv.terminator setting
replace the overly absolute "cannot provide any service" wording for the local backend with wording that matches the current physical import behavior and limitations
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Summary by CodeRabbit
Documentation
Clarified that, with TiDB Lightning v7.1.0 or later and TiDB v6.1.0 or later, local-backend imports pause scheduling by default only for Regions in the target table. The cluster can provide limited service during imports, though performance may still be affected.
Explained that strict-format CSV files can be split into 256 MiB chunks when the configured, non-empty line terminator matches the source file.
Clarified SQL file naming and matching requirements, and updated configuration examples to show port values without quotes.
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Review comments at @tidb-lightning/tidb-lightning-data-source.md:
- Line 256: **Document the strict-format terminator dependency in the
configuration reference.**
The strict-format section requires a non-empty `mydumper.csv.terminator`. The
`terminator` entry in `tidb-lightning/tidb-lightning-configuration.md` says that
the empty default is valid and accepts both LF and CRLF, and it does not mention
strict-format. Readers can reasonably conclude that the default is safe when
they enable `strict-format`.
Add the strict-format requirement to the `terminator` entry in
`tidb-lightning/tidb-lightning-configuration.md`. State what happens when
`strict-format` is enabled and the value is empty. Keep the existing default
description, and make the strict-format note consistent with the wording in
`tidb-lightning/tidb-lightning-data-source.md`.
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The documentation clarifies local-backend service availability, SQL filename matching, and the mydumper.csv.terminator setting for strict-format CSV chunk splitting. It also updates example configuration values.
The guides describe limited service during local-backend imports and the default scheduling pause for the target table’s Regions. The SQL guide adds filename matching guidance. Example port values no longer use quotes.
The documentation states that chunk splitting requires mydumper.csv.terminator to match the source file’s non-empty line terminator. The examples include a terminator setting.
pingcap/docs#24586: Updates the Japanese CSV import guide with the same strict-format CSV splitting behavior.
Suggested reviewers:qiancai
Merge Risk: Minimal · up to 30760
The examples now specify the required terminator. The existing configuration-reference omission remains, but this change does not worsen it.
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tidb-lightning/tidb-lightning-data-source.md
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TiDB Lightning works best when the input files have a uniform size of around 256 MiB. When the input is a single huge CSV file, TiDB Lightning can only process the file in one thread, which slows down the import speed.
This can be fixed by splitting the CSV into multiple files first. For the generic CSV format, there is no way to quickly identify where a row starts or ends without reading the whole file. Therefore, TiDB Lightning by default does *not* automatically split a CSV file. However, if you are certain that the CSV input adheres to certain restrictions, you can enable the `strict-format` setting to allow TiDB Lightning to split the file into multiple 256 MiB-sized chunks for parallel processing.
This can be fixed by splitting the CSV into multiple files first. For the generic CSV format, there is no way to quickly identify where a row starts or ends without reading the whole file. Therefore, TiDB Lightning by default does *not* automatically split a CSV file. However, if you are certain that the CSV input adheres to certain restrictions, you can enable the `strict-format` setting to allow TiDB Lightning to split the file into multiple 256 MiB-sized chunks for parallel processing. To use `strict-format`, you need to also set `mydumper.csv.terminator` to the actual non-empty line terminator in the source file.
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Minor · Data Integrity & Integration · Quick win
Supported by static analysis
Script executed:
nl -ba tidb-lightning/tidb-lightning-data-source.md | sed -n '116,130p;250,268p'
nl -ba tidb-lightning/tidb-lightning-configuration.md | sed -n '425,452p'
Repository: pingcap/docs
Length of output: 3240
Document the strict-format terminator dependency in the configuration reference.
The strict-format section requires a non-empty mydumper.csv.terminator. The terminator entry in tidb-lightning/tidb-lightning-configuration.md says that the empty default is valid and accepts both LF and CRLF, and it does not mention strict-format. Readers can reasonably conclude that the default is safe when they enable strict-format.
Add the strict-format requirement to the terminator entry in tidb-lightning/tidb-lightning-configuration.md. State what happens when strict-format is enabled and the value is empty. Keep the existing default description, and make the strict-format note consistent with the wording in tidb-lightning/tidb-lightning-data-source.md.
# "local": Default backend. The local backend is recommended to import large volumes of data (1 TiB or more). During the import, the target TiDB cluster cannot provide any service.
# "local": Default backend. The local backend is recommended to import large volumes of data (1 TiB or more). During the import, the target TiDB cluster can provide only limited service. If your TiDB Lightning version is v7.1.0 or later and your TiDB version is v6.1.0 or later, TiDB Lightning pauses scheduling only for the target table's Regions by default. The import might still affect cluster performance.
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Please clarify what “limited service” means. Users must not run DDL or DML on the target table during import, and reads may return inconsistent data. Otherwise, readers may think it is safe to keep using that table. Please add this warning to all four updated descriptions.
Put all the SQL files in the same directory, like `/data/my_datasource/` or `s3://my-bucket/sql-backup`. TiDB Lightning recursively searches for all `.sql` files in this directory and its subdirectories.
Put all the SQL files in the same directory, like `/data/my_datasource/` or `s3://my-bucket/sql-backup`. TiDB Lightning recursively searches for `.sql` files in this directory and its subdirectories, but the data files must follow the default naming patterns such as `${db_name}.${table_name}.sql` or `${db_name}.${table_name}.001.sql`. If your SQL files use different names, configure [`[[mydumper.files]]`](/tidb-lightning/tidb-lightning-data-source.md#match-customized-files) to match them.
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Please note that custom [[mydumper.files]] rules turn off default file matching unless users set default-file-rules = true under [mydumper]. This can skip other data files or the schema files needed in Step 2. Please mention this setting, or tell users to add rules for all files they need.
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area/migrateIndicates that the Issue or PR belongs to the area of TiDB migration tools.area/tidb-lightningIndicates that the Issue or PR belongs to the area of TiDB Lightning.contributionThis PR is from a community contributor.needs-cherry-pick-release-8.5Should cherry pick this PR to release-8.5 branch.ONCALLRelates to documentation oncall.size/MDenotes a PR that changes 30-99 lines, ignoring generated files.translation/welcomeWaits for a contributor to translate this PR and create a PR to the pingcap/docs-cn repository.type/bugfixThis PR fixes a bug.
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What is changed, added or deleted? (Required)
This PR fixes several TiDB Lightning documentation inconsistencies in the SQL, CSV, and Parquet import guides and aligns the shared Lightning references:
tidb.portandtidb.status-portplaceholders in the import-guide TOML examples so they match the documented integer configuration types[[mydumper.files]]is configuredstrict-formatexamples to include the required non-emptymydumper.csv.terminatorsettinglocalbackend with wording that matches the current physical import behavior and limitationsWhich TiDB version(s) do your changes apply to? (Required)
Tips for choosing the affected version(s):
By default, CHOOSE MASTER ONLY so your changes will be applied to the next TiDB major or minor releases. If your PR involves a product feature behavior change or a compatibility change, CHOOSE THE AFFECTED RELEASE BRANCH(ES) AND MASTER.
For details, see tips for choosing the affected versions.
What is the related PR or file link(s)?
Do your changes match any of the following descriptions?
Summary by CodeRabbit