Db2 EXPLAIN fails if using JDBC and certificate authorization.
ACF/DB2 Release : 1.3
IBM DB2 release 12 and 13
Excerpt from IBM doc:
A remote application connects using client certificate authorization to a Db2 for z/OS server configured with Broadcom ACF2. The application issues an SQL EXPLAIN which fails with SQLCODE -219. When Db2 queries the AT-TLS information for the connection, ACF2 returned a null terminated string for the userid
associated with the client certificate. Db2 did not process the null terminated userid correctly.
NOTE: This issue can affect any SQL statements containing unqualified object references and can result in other errors such as SQLCODE -204.
IBM PTF PH52584: EXPLAIN MAY FAILS VIA JDBC, POSSIBLY B/C OF X'00' IN SQLID
APARS UI91237 for DB2 v12 and UI91238 for DB2 v13