Singer Regex Optimization for Pattern.compile calls

[chesswithmihir]

Problem:

• Singer repeatedly compiles the same regex patterns when processing log files, causing unnecessary CPU overhead in high-throughput scenarios.

Solution:

• Added PatternCache utility class with thread-safe caching of compiled Pattern objects
• Integrated caching into TextLogFileReaderFactory and LogStreamManager
• Added comprehensive unit tests to verify caching behavior

Impact:

• Reduces regex compilation overhead by reusing cached patterns, improving performance for log processing pipelines with frequent pattern matching.