Optimize key expiration check with branch prediction hint

[stav-bentov]

Optimized the key expiration check logic with branch prediction hints, enhancing performance during runtime.

• Added a conditional check if (unlikely(dbSize(db) > 0)) before calling expireIfNeededWithDictIndex. This optimization:
  • Reduces unnecessary function calls when the database is empty.
  • Improves branch prediction efficiency by using the unlikely hint.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 71.03%. Comparing base (9071a5c) to head (8848500).
Report is 9 commits behind head on unstable.

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable    #1632      +/-   ##
============================================
+ Coverage     70.85%   71.03%   +0.17%     
============================================
  Files           121      121              
  Lines         65169    65175       +6     
============================================
+ Hits          46176    46294     +118     
+ Misses        18993    18881     -112     

Files with missing lines	Coverage Δ
src/db.c	89.73% <100.00%> (+0.16%)	⬆️

... and 14 files with indirect coverage changes

[madolson]

Why is it "unlikely" that dbSize > 0? This doesn't make any sense. Can you publish the benchmarking your did to find this?