Join pushdown not work on varchar datatype

[alisanguo]

Trino version: 417 and elasticsearch version is 6.8.
We use elasticsearch connector.
JoinPushdown works fine when joining 2 tables on integer datatype columns. But it does not work when joining 2 tables on varchar datatype columns.

varchar datatype columns loan_no/debt_no：very slowly

[alisanguo]

integer datatype columns user_id：get result very fast