graphql-java is a mature and optimised library. So its increasingly difficult to find performance improvements that really stand out.

This leads us to the 1% club where we need to do a bunch of work to get a small 1% gain

This issue tries to capture investigations of these 1%'ers and hence be a list of possible micro improvements

Profiler investigations - memory

Running ComplexQueryPeformance as load and using JProfiler

The biggest objects are as follows

"graphql.execution.ExecutionStrategyParameters", 4% of memory
"graphql.execution.ExecutionStrategyParameters$Builder", 4% of memory use
"graphql.execution.ExecutionStepInfo" 2%
"graphql.execution.ExecutionStepInfo$Builder", 2%
"graphql.execution.NonNullableFieldValidator", 2%
"graphql.execution.FetchedValue", 2%

I have PRS that try to reduce all these - eg either remove the builder usage for "transforms" (ExecutionStrategyParameters and ExecutionStepInfo)

or avoid re-allocating per field (NonNullableFieldValidator and FetchedValue)

#3924
#3929
#3934
#3935

The builder ones reduce by memory per type by half right - because we no longer create a builder to actually create a ExecutionStepInfo say

interesting future things to look into

• "graphql.util.IntraThreadMemoizedSupplier", 4%
  ** why so heavy - do we strictly need it

• "graphql.schema.FieldCoordinates" 2%
  ** can we avoid this some how - flyweights?

• "graphql.schema.PropertyFetchingImpl$CacheKey", 2%
  ** can we avoid this some how - flyweights?

• "com.google.common.collect.SingletonImmutableList", 2%
  ** why so high?? Are we wrapping something for no reason

• "graphql.schema.DataFetcherFactoryEnvironment", 2%
  ** "graphql.schema.DataFetcherFactoryEnvironment$Builder" 2%
  ** this can go I think

asserts cost cpu and memory

eg :

this.executionStepInfo = assertNotNull(executionStepInfo, () -> "executionStepInfo is null");

These asserts are great for code reasons - but they cost something to run

Can we use the jspecify annotations here and remove these because static analysis is giving us the safety ?

cpu hot spots to look into

• 1.6% - 1,256 ms - 1,372,469 hot spot inv. graphql.schema.GraphQLCodeRegistry.getDataFetcherImpl

• 1.5% - 1,190 ms - 7,119,736 hot spot inv. graphql.schema.GraphQLTypeUtil.unwrapNonNull

• 1.5% - 1,209 ms - 7,088,722 hot spot inv. graphql.execution.ExecutionStepInfo.getUnwrappedNonNullType

• 1.3% - 1,010 ms - 12,160,902 hot spot inv. graphql.Assert.assertNotNull(java.lang.Object, java.util.function.Supplier)

• 1.0% - 786 ms - 1,485,657 hot spot inv. graphql.execution.ExecutionStrategy.unboxPossibleDataFetcherResult

This is an interesting one - its called on DataFetch BUT its also called in completeValueForList

meaning can a DF returns a DataFetcherResult that itself is a list of DataFetcherResult of values. Is this even remotely sensible?? Can we kill it in lists the name of 1% ??