cardinality null cause wrong meta_json,this may cause wrong Optimization.

[wakaka2019]

Describe the bug

Environment

• OS Version and CPU Arch(uname -a):
  Linux sqless 3.10.0-957.27.2.el7.x86_64 #1 SMP Mon Jul 29 17:46:05 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
• Component Version:
  latest

Fast Reproduce Steps(Required)
cardinality null cause wrong result.

Steps to reproduce the behavior:

Expected behavior
{"schema":"DB1","table":"TABLE1",
"name":"INDEX1","column":"COL1",
"cardinality":RIGHT NUMBER,"unique":false}
Actual Behavior
wrong result
Additional context

[wakaka2019]

1、cardinality的值为NULL 这个建议会走错了吗？
2、生成的索引名字是不是太长了，还有重复的两列
3、我创建了给出建议的这个索引，然后再去页面点优化建议 ，他还是提示这些建议

[github-actions]

Stale issue message