[jdt-dev] Revert Bug 481323 - substring/subword completion

[Gunnar Wagenknecht <gunnar@xxxxxxxxxxxxxxx>]

Dear JDT Team,

After making progress with the Java 11 related performance issues, I discovered a huge regression that was introduced in 4.17.
https://bugs.eclipse.org/bugs/show_bug.cgi?id=481323#c21

While I see value in substring and subword completion, the performance degradation is not acceptable IMO.

Here are the timings from SearchableEnvironment#findTypes:
- as is today: 2134ms
- with -Djdt.codeCompleteSubstringMatch=false: 1649ms
- with commit reverted: 794ms

So even disabling it on the command line does not restore the previous performance.

Can this be reverted and implemented again in such a way that there won't be any performance hit if it's turned off?

-Gunnar

-- 
Gunnar Wagenknecht
gunnar@xxxxxxxxxxxxxxx, http://guw.io/