From my understanding, `work_mem` is the maximum available memory per operation and not just per connection. If you have a stored procedure with loops and/or many nested operations, that can quickly get quite big.

One trick worth noting, is that you can override the working memory at the transaction level. If you have a query you know needs more memory (e.g doing a distinct or plain sorting on a large table), within a transaction you can do:

`set local work_mem = '50MB'`

That will override the setting for operations inside this transaction only.