Auto search on the prompt/lookup table is handy, so users can see the immediate search results as soon as he/she click lookup icon. However, this can be extremely painfully slow if you have ten/hundred-thousandths rows in the table.
From PeopleTools 8.44, the lookup/prompt table initial auto search can be suppressed by adding the record definition name into "Lookup Exclusion Table".
Here is the path:
PeopleTools > Utilities > Administration > Lookup Exclusion Table