关于ws表是否需要新增ses字段索引的技术咨询

Great question! Let's work through this using the details you've provided to make a clear call:

Key Factors to Consider #

The value of an index entirely depends on how you use the ses field in your queries—this is the most critical context we're working with right now, but we can break down the scenarios based on common use cases:

When You Should Create an Index on ses

• If you run any queries that filter, sort, or join using the ses field (e.g., SELECT * FROM ws WHERE ses = 'abc123', ORDER BY ses DESC, or joining another table on ses), then absolutely create the index.
  • Your ws table holds 3 months of data—even without knowing the exact row count, this is likely a non-trivial dataset. Without an index, these queries would trigger a full table scan, which will be far slower than the performant id-based queries you're used to (thanks to the existing id index).
  • The performance gain from avoiding full scans will almost always outweigh the minor overhead of index maintenance on writes (INSERT/UPDATE/DELETE).

When You Should Not Create an Index on ses

• If you never use ses in any query filters, sorts, or joins, skip the index entirely.
  • Indexes take up extra storage space and add small but consistent overhead to every write operation on the table. There's no point in paying that cost if you never get a performance benefit from it.

Quick Additional Check #

If you're unsure about current or future use of ses, take a look at your application's existing SQL queries, or talk to your team about any planned features that might involve querying by ses. That will give you the final clarity you need.

内容的提问来源于stack exchange，提问作者Max