mysqli execute returns false with large result set

I have a MySQL query that works fine until the result set gets large (in this case large means about 13,000 rows) at which point execute returns false. When I check the mysqli error,开发者_运维百科 It gives me the following:

Duplicate entry '13054' for key 'group_key'

There is no group_key field in any of my tables, so this must be in the temp table mysql populates. The error occurs across several different databases. Any ideas?

---

That's not a field, that's the name of a key. You'd need to look at show create table XXX to find the key names. MySQL requires each key have a name, but its auto-generated names are far uglier than this, so most likely this is a user-defined key name - look at the DDL for the tables involved in your query and look for a 'group' field.