Allow user configurable regex library for queries

[itschrispeck]

This PR addresses #12628

This provides functionality to configure a regex library that will be used during query execution.

• PatternFactory.compile(...) is used in place of Pattern.compile(...)
• Pattern interface added maintains the same semantics as java.util.Pattern
• Matcher interface added maintains the same semantics as java.util.Matcher

A new config is added: pinot.server.query.regex.class
Valid values for this config are: JAVA_UTIL or RE2J (it might be better to accept class names instead?).

Some testing showed regex libraries have very different strengths/weaknesses, so it seemed best to allow users to choose an implementation that works well for them.

Default behavior is unchanged.

tag: feature

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 93.75000% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 62.20%. Comparing base (59551e4) to head (72cff23).
Report is 431 commits behind head on master.

Files	Patch %	Lines
.../pinot/server/starter/helix/BaseServerStarter.java	0.00%	2 Missing ⚠️
...rg/apache/pinot/common/utils/regex/RegexClass.java	83.33%	1 Missing ⚠️

Additional details and impacted files

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##             master   #13005      +/-   ##
============================================
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  Lines        133233   137901    +4668     
  Branches      20636    21327     +691     
============================================
+ Hits          82274    85776    +3502     
- Misses        44911    45734     +823     
- Partials       6048     6391     +343     

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[richardstartin]

Why not just replace the implementation to keep the interface simple and easy to use? If Java's built in regular expressions have the edge somewhere, it's probably a pretty small edge, and it would be nice to avoid backtracking by default.

[itschrispeck]

Why not just replace the implementation to keep the interface simple and easy to use? If Java's built in regular expressions have the edge somewhere, it's probably a pretty small edge, and it would be nice to avoid backtracking by default.

I don't have a good understanding of how Pinot's users use regex, but from searching it seems that the median latency/memory usage of re2j is higher than Java's built in library. It'd also become a backwards incompatible change due to feature gaps. In general I don't think users would be primarily using Pinot for regex filtering (i.e. should we have an optimized path for the average case or focus on worst case performance?), but that's my conjecture.

Some references:
https://github.com/DaniilRoman/re2j_test
google/re2j#162
google/re2j#12

If there is a consensus that an outright replacement is acceptable I'm happy to go that route.

[deemoliu]

+1 on making this configurable in the first version. And this change, it will be easier for us to benchmark with different library.

There are some known cases re2j doesn't outperform the current implementation, so it's a good idea to on hold the replacement of the existing library.

We can do another thorough analysis on when re2j is more efficient and when it's not, and make a proposal on the default behavior of regex.

[chenboat]

Great feature to add to Pinot.