v1.2.646-nightly

What's Changed

Exciting New Features ✨

• feat(query): Reduce serialisation memory usage when spilling to local disk by @forsaken628 in #16580
• feat(query): Support show dictionaries DQL. by @Winnie-Hong0927 in #16602

Thoughtful Bug Fix 🔧

• fix: subquery returns wrong results under cluster by @xudong963 in #16606
• fix(query): ntile frame should be unbounded by @TCeason in #16604

Code Refactor 🎉

• refactor: isolate session_id and session states of diff users. by @youngsofun in #16592

Others 📒

• chore: refine table sample tests by @xudong963 in #16600
• chore(query): add more logs on aggregation by @sundy-li in #16552

Full Changelog: v1.2.645-nightly...v1.2.646-nightly