What's the better way to set an initial customer increment id?

Question

This SO Question has two answers:

1. Set the AUTO_INCREMENT for the customer_entity table.
2. Set the increment_prefix and increment_last_id for the customer entity in the entity_store table.

The second seems more correct (or at least more internally consistent with Magento), but it doesn't seem to work as far as I can tell. I've tried it multiple times with different configurations (with store_id 0, store_id 1 and setting the increment_per_store in eav_entity_type to 1 for customer), but each time I register as a new customer that customer's increment_id remains NULL and the entity_id increments from 1.

I'm reasonably sure the AUTO_INCREMENT approach will work, but given the fact that the increment_last_id works for order numbers, the second approach has a number of upvotes and seems more Magento-like I'd like to understand if that answer is more correct and I'm just doing it wrong.

Answer 1

Only the second of the two options will actually adjust the increment_id of the customer entity. The first method will change the entity_id field instead of the increment_id. So I think you are correct in favoring the second option.

As far as getting that method to work, Magento will only use the eav_entity_store.increment_last_id for the customer entities when a "Generate Human-Friendly Customer ID" setting is set to "Yes" in the config. See Mage_Customer_Model_Resource_Customer::setNewIncrementId for where this check happens happens.

You can find this setting in the Magento admin at System -> Configuration -> Customer Configuration -> Create New Account Options -> Generate Human-Friendly Customer ID.