Bug Report: Table GC Regex Not Matching Lowercase State Names

[yushuqin]

Overview of the Issue

Problem: When MySQL is configured with lower_case_table_names=1, all table names are stored in lowercase. Vitess generates GC table names like vt_HOLD, but MySQL stores them as vt_hold. The old regex only matched uppercase state names, causing TableGC to fail to recognize, and stay forever.

Solution: The fix makes the GC table recognition case-insensitive while maintaining backward compatibility with existing uppercase table names.
slackhq#753

Reproduction Steps

• mysql configuration: lower_case_table_names=1
• do onlineddl schema change
• tables starting with vt_hold will stay forever, never be cleaned up

Binary Version

19.0.7

Operating System and Environment details

Ubuntu

Log Fragments

[dbussink]

• mysql configuration: lower_case_table_names=1

I'd like to also clarify that this mode in MySQL is currently not explicitly supported in Vitess. There's many other places where bugs could occur since only lower_case_table_names=0 is explicitly supported / known to work with Vitess. This like the Vitess parser, query planner etc. follow the case sensitive rules of lower_case_table_names=0.

If you haven't run into other problems except for this one, that's by accident more than a deliberate design in Vitess.

[shlomi-noach]

Old table names to be removed via #18981, see tracking issue #14582.

This issue applies to unsupported versions only.