Improve Utf8GraphQLParser and Utf8Helper performance

[michaelstaib]

• Add first-byte keyword dispatch in ParseDefinition and ParseTypeExtension
• Add ParseOperationDefinition(OperationType) overload to skip redundant matching
• Add empty list singletons for ParseImplementsInterfaces and ParseUnionMemberTypes
• Add list capacity hints for definitions, selections, arguments, and values
• Replace HexToDecimal switch with byte[256] lookup table
• Split ProcessEscapeSequence into inlined hot path and NoInlining cold path
• Change SIMD V256/V128 from else-if to sequential for V128 remainder processing
• Replace byte-by-byte scalar tail with IndexOf + CopyTo bulk copy
• Add well-known name interning in GetName() for ~35 common GraphQL names
• Add parser and unescape benchmarks

[github-actions]

Fusion Gateway Performance Results

Simple Composite Query

	Req/s	Err%
Constant (50 VUs)	2930.15	0.00%
Ramping (0-500-0 VUs)	3170.62	0.00%

Response Times & Query

	Min	Med	Avg	P90	P95	Max
Constant	0.72ms	15.06ms	16.83ms	30.50ms	35.64ms	172.37ms
Ramping	0.81ms	69.04ms	70.20ms	131.29ms	148.49ms	253.44ms

query TestQuery {
  topProducts(first: 5) {
    inStock
    name
    price
    shippingEstimate
    upc
    weight
    reviews {
      id
      body
      author {
        id
        username
        name
      }
    }
  }
}

---

Deep Recursion Query

	Req/s	Err%
Constant (50 VUs)	741.33	0.00%
Ramping (0-500-0 VUs)	824.74	0.00%

Response Times & Query

	Min	Med	Avg	P90	P95	Max
Constant	9.02ms	62.53ms	65.90ms	81.46ms	90.72ms	342.37ms
Ramping	1.82ms	253.48ms	261.33ms	527.75ms	565.67ms	698.34ms

query TestQuery {
  users {
    id
    username
    name
    reviews {
      id
      body
      product {
        inStock
        name
        price
        shippingEstimate
        upc
        weight
        reviews {
          id
          body
          author {
            id
            username
            name
            reviews {
              id
              body
              product {
                inStock
                name
                price
                shippingEstimate
                upc
                weight
              }
            }
          }
        }
      }
    }
  }
  topProducts(first: 5) {
    inStock
    name
    price
    shippingEstimate
    upc
    weight
    reviews {
      id
      body
      author {
        id
        username
        name
        reviews {
          id
          body
          product {
            inStock
            name
            price
            shippingEstimate
            upc
            weight
          }
        }
      }
    }
  }
}

---

Variable Batching Throughput

	Req/s	Err%
Constant (50 VUs)	23265.72	0.00%
Ramping (0-500-0 VUs)	18488.74	0.00%

Response Times & Query

	Min	Med	Avg	P90	P95	Max
Constant	0.10ms	1.74ms	2.10ms	4.00ms	4.86ms	46.34ms
Ramping	0.10ms	9.51ms	11.43ms	23.28ms	28.09ms	99.24ms

query TestQuery($upc: ID!, $price: Long!, $weight: Long!) {
  productByUpc(upc: $upc) {
    inStock
    shippingEstimate(weight: $weight, price: $price)
  }
}

Variables (5 sets batched per request)

[
  { "upc": "1", "price": 899, "weight": 100 },
  { "upc": "2", "price": 1299, "weight": 1000 },
  { "upc": "3", "price": 15, "weight": 20 },
  { "upc": "4", "price": 499, "weight": 100 },
  { "upc": "5", "price": 1299, "weight": 1000 }
]

---

Run 22141176141 • Commit b473e1b • Wed, 18 Feb 2026 13:54:39 GMT

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 0.00%. Comparing base (6a3b7a3) to head (094ff36).
⚠️ Report is 769 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #9134       +/-   ##
==========================================
- Coverage   74.16%       0   -74.17%     
==========================================
  Files        2677       0     -2677     
  Lines      140790       0   -140790     
  Branches    16371       0    -16371     
==========================================
- Hits       104421       0   -104421     
+ Misses      30774       0    -30774     
+ Partials     5595       0     -5595     

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