Fix performance regression in split by avoiding allocating substring per char #237
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JoshRosen
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stephenamar-db
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Dec 12, 2024
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This PR fixes a performance regression from #227 / 4c85bde which I overlooked in review:
When generalizing the optimized non-Pattern-based split code, that commit introduced a
.substring()on each character, producing tons of garbage.Instead, I think we can do a
.startsWith(splitPattern, i): this should be much faster because it will avoid unnecessary garbage string creation (plus I'm pretty sure thatstartsWithis optimized in modern JDKs).I also removed the use of
breakableand replaced it with an update to thewhilecondition.