epriestley 086a125ad5 Improve performance of Ferret engine ngram extraction, particularly for large input strings ... Summary: See PHI87. Ref T12974. The `array_slice()` method of splitting the string apart can perform poorly for large input strings. I think this is mostly just the large number of calls plus building and returning an array being not entirely trivial. We can just use `substr()` instead, as long as we're a little bit careful about keeping track of where we're slicing the string if it has UTF8 characters. Test Plan: - Created a task with a single, unbroken blob of base64 encoded data as the description, roughly 100KB long. - Saw indexing performance improve from ~6s to ~1.5s after patch. - Before: https://secure.phabricator.com/xhprof/profile/PHID-FILE-nrxs4lwdvupbve5lhl6u/ - After: https://secure.phabricator.com/xhprof/profile/PHID-FILE-6vs2akgjj5nbqt7yo7ul/ Reviewers: amckinley Reviewed By: amckinley Maniphest Tasks: T12974 Differential Revision: https://secure.phabricator.com/D18649		2017-09-27 10:41:39 -07:00
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PhabricatorFerretEngineTestCase.php	Improve performance of Ferret engine ngram extraction, particularly for large input strings	2017-09-27 10:41:39 -07:00