Add TiKV resource dimensions for topsql

[jiong-nba]

TiKV TopSQL Resource Dimensions

Overview

This PR extends the existing TiKV TopSQL source to consume and export the resource dimensions introduced by tikv/tikv#19837.

It keeps protobuf decoding, per-second Top N filtering, others aggregation, downsampling, and emitted TopSQL metrics consistent for the following fields:

• Network input/output bytes
• Logical read/write bytes
• RocksDB block read count

Key Features

1. Extended TiKV Resource Usage Protocol

Add the following fields to GroupTagRecordItem using the field numbers defined by kvproto:

• network_in_bytes = 5
• network_out_bytes = 6
• logical_read_bytes = 7
• logical_write_bytes = 8
• rocksdb_block_read_count = 9

2. TopSQL Metric Output

Export the new TiKV resource dimensions as TopSQL metrics:

• topsql_network_in_bytes
• topsql_network_out_bytes
• topsql_logical_read_bytes
• topsql_logical_write_bytes
• topsql_rocksdb_block_read_count

3. Resource-Aware Top N Filtering

• Select candidates independently by CPU, combined network traffic, logical reads, logical writes, and RocksDB block reads.
• Keep the union of candidates selected by each resource dimension, matching TiKV's resource metering semantics.
• Merge all fields from evicted records into the per-second others record.
• Merge multiple existing others records at the same timestamp instead of overwriting them.
• Preserve all resource dimensions during downsampling.

Tests

cargo test --lib sources::topsql::upstream::tikv::parser::tests -- --nocapture
cargo test --lib --features nextgen sources::topsql::upstream::tikv::parser::tests -- --nocapture
cargo check --workspace --all-targets
cargo check --workspace --all-targets --features nextgen
cargo fmt --all -- --check
git diff --check

Related changes:

• tikv/tikv#19837
• pingcap/kvproto#1498
• tidbcloud/vector-extensions#63

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[Copilot]

🟡 Not ready to approve

The updated Top-N cutoff logic has a tie-handling bug and also risks u64 overflow when summing network bytes, which can lead to incorrect filtering/aggregation.

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Pull request overview

This PR extends the TiKV TopSQL upstream parser to decode and emit additional resource-dimension metrics (network I/O bytes, logical read/write bytes, RocksDB block read count) while preserving existing behaviors like per-second Top-N filtering, others aggregation, and downsampling.

Changes:

• Extend GroupTagRecordItem (protobuf + Rust handling) to include 5 new TiKV resource usage fields.
• Emit new TopSQL metrics for the added resource dimensions.
• Update Top-N filtering, others merging behavior, and downsampling logic/tests to account for the new dimensions.

File summaries

File	Description
src/sources/topsql/upstream/tikv/parser.rs	Adds field merges, resource-aware Top-N selection, emits new metrics, and extends downsampling/tests.
src/sources/topsql/upstream/tikv/mock_upstream.rs	Extends mock TiKV metering records with the new resource fields.
src/sources/topsql/upstream/consts.rs	Adds metric name constants for the new TiKV resource dimensions.
proto/tikv.proto	Extends the protobuf message with new fields and field numbers (5–9).

Review details

• Files reviewed: 4/4 changed files
• Comments generated: 1
• Review effort level: Lite

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