Storages: Fix the statistics of user_read_bytes and add metrics (#10396)

[ti-chi-bot]

This is an automated cherry-pick of #10396

What problem does this PR solve?

Issue Number: ref #10380

• ConcatSkippableBlockInputStream
  • When generating MVCC bitmaps using DeltaIndex, row_id is generated in DeltaMergeBlockInputStream. The getPlacedStream method sets the need_row_id parameter to false when obtaining the stable stream. Therefore, in ConcatSkippableBlockInputStream, need_row_id cannot be used to determine whether MVCC is involved.
  • This can be resolved by switching to a check based on read_tag.
• DeltaValueReader
  • When we use getInputStreamNormal to read data, delta data is read through DeltaValueReader. Thus, DeltaValueReader needs to add statistics for user_read_bytes.
• VersionChain
  • Track the read bytes consumed during the construction of MVCC bitmaps.
• ScanContext
  • Encapsulate the reporting of primary user_read_bytes and metrics within ScanContext.
• Mark the read operations for updating DeltaIndex and VersionChain as ReadTag::Internal.
• TiFlashMetrics
  • Add storage-layer RU (Resource Usage) monitoring.

What is changed and how it works?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

None

[ti-chi-bot]

@JinheLin This PR has conflicts, I have hold it.
Please resolve them or ask others to resolve them, then comment /unhold to remove the hold label.

[ti-chi-bot]

@ti-chi-bot: ## If you want to know how to resolve it, please read the guide in TiDB Dev Guide.

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[JinheLin]

/hold

testing

[JinheLin]

/unhold

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: JaySon-Huang, JinheLin

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• OWNERS [JaySon-Huang,JinheLin]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-09-08 16:27:52.936649448 +0000 UTC m=+292339.496530935: ☑️ agreed by JaySon-Huang.
• 2025-09-09 01:17:14.069289234 +0000 UTC m=+324100.629170721: ☑️ agreed by JinheLin.