Cache results of Converter lookup in GenericConversionService to improve performance [SPR-7110]

[spring-projects-issues]

Keith Donald opened SPR-7110 and commented

Currently every call into the ConversionService results in a fairly-involved search to match the Converter to use for a given source/target TypeDescriptor pair. Performance could likely be improved significantly by caching the results of converter lookup operations.

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Affects: 3.0.2

Issue Links:

• Optimize GenericConversionService.findConverterForClassPair [SPR-6749] #11415 Optimize GenericConversionService.findConverterForClassPair

[spring-projects-issues]

Keith Donald commented

Now Caching Converter lookup results to improve conversion service performance.

[spring-projects-issues]

Keith Donald commented

Some performance benchmarks on my modest Macbook laptop:

converting 1,000,000 int to string with caching: 603 ms
converting 1,000,000 int to string without caching: 17306 ms

converting 1,000,000 list<string> (size=3) to list<int> with caching: 3599 ms
converting 1,000,000 list<string> (size =3) to list<int> without caching: 21634 ms

[spring-projects-issues]

Keith Donald commented

Latest benchmarks after additional optimizations:

StopWatch 'integer->string conversionPerformance': running time (millis) = 905

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ms % Task name

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00701 077% convert 4,000,000 with conversion service
00204 023% convert 4,000,000 manually

StopWatch 'list<string> -> list<integer> conversionPerformance': running time (millis) = 2029

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ms % Task name

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01504 074% convert 4,000,000 with conversion service
00525 026% convert 4,000,000 manually

StopWatch 'map<string, string> -> map<string, integer> conversionPerformance': running time (millis) = 3789

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ms % Task name

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02171 057% convert 4,000,000 with conversion service
01618 043% convert 4,000,000 manually

WITHOUT CACHING is significantly slower:

StopWatch 'integer->string conversionPerformance': running time (millis) = 36184

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ms     %     Task name

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35984  099%  convert 4,000,000 with conversion service
00200  001%  convert 4,000,000 manually

StopWatch 'list<string> -> list<integer> conversionPerformance': running time (millis) = 11032

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ms     %     Task name

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10453  095%  convert 4,000,000 with conversion service
00579  005%  convert 4,000,000 manually

StopWatch 'map<string, string> -> map<string, integer> conversionPerformance': running time (millis) = 46752

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ms     %     Task name

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45089  096%  convert 4,000,000 with conversion service
01663  004%  convert 4,000,000 manually