add a new guide on mastering partitioned tables in TiDB

[shaoxiqian]

• Query optimization with partition pruning
• Performance comparison: Non-Partitioned vs Local Index vs Global Index
• Data cleanup efficiency: TTL vs DROP PARTITION
• Partition drop performance: Local Index vs Global Index
• Strategies to mitigate write hotspot issues with hash/key partitioning
• Partition management challenges and best practices
  • Avoiding read/write hotspots on new partitions
  • Using PRE_SPLIT_REGIONS, SHARD_ROW_ID_BITS, and region splitting
• Converting between partitioned and non-partitioned tables
  • Batch DML, Pipeline DML, IMPORT INTO, and Online DDL efficiency comparison

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[gemini-code-assist]

Summary of Changes

Hello @shaoxiqian, 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!

This pull request introduces a comprehensive guide on mastering partitioned tables in TiDB. It covers critical aspects such as optimizing query performance through partition pruning and global indexes, efficiently managing bulk data deletion with DROP PARTITION versus TTL, mitigating write hotspots using hash/key partitioning, and best practices for managing new range partitions. The guide also provides a detailed comparison of methods for converting tables between partitioned and non-partitioned states, offering practical insights and recommendations for effective TiDB environment management.

Highlights

• Query Optimization: Details how partition pruning enhances query efficiency and compares performance across non-partitioned, local index, and global index configurations, providing insights into when to use each.
• Bulk Data Deletion: Explores the efficiency of data cleanup using TTL versus direct partition drops, highlighting the significant performance advantages of DROP PARTITION and its implications for local vs. global indexes.
• Write Hotspot Mitigation: Discusses strategies, particularly hash/key partitioning, to alleviate write hotspot issues caused by monotonically increasing primary keys, improving load distribution and throughput.
• Partition Management: Addresses common challenges like read and write hotspots in new range partitions and provides solutions using SHARD_ROW_ID_BITS, PRE_SPLIT_REGIONS, and region splitting for both NONCLUSTERED and CLUSTERED tables.
• Table Conversion Methods: Compares the efficiency of various methods (Batch DML, Pipeline DML, IMPORT INTO, Online DDL) for converting between partitioned and non-partitioned tables, offering recommendations for optimal performance.

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[gemini-code-assist]

Code Review

This pull request adds a comprehensive guide on using partitioned tables in TiDB. The document covers various aspects from query optimization and data cleanup to mitigating hotspots and managing partitions. My review focuses on improving clarity, consistency, and adherence to the documentation style guide. I've suggested changes to use sentence case for headings, ensure consistent terminology for 'global index' and 'local index', and improve phrasing for better readability. I also found some minor typos and inconsistencies in code examples that could confuse readers.

[shaoxiqian]

/retest

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
Once this PR has been reviewed and has the lgtm label, please ask for approval from hfxsd. For more information see the Code Review Process.
Please ensure that each of them provides their approval before proceeding.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[shaoxiqian]

/test pull-verify

[shaoxiqian]

/test pull-verify

[dveeden]

Please add to the TOC as per my previous comment

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-10-03 08:14:25.172266392 +0000 UTC m=+418045.428997792: ✖️🔁 reset by dveeden.
• 2025-10-14 11:57:15.919784395 +0000 UTC m=+181741.997036955: ✖️🔁 reset by dveeden.
• 2025-10-15 07:23:04.318583067 +0000 UTC m=+251690.395835627: ☑️ agreed by dveeden.

[ti-chi-bot]

@shaoxiqian: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-verify	0dd7df8	link	true	/test pull-verify

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