SQL> select object_name,object_type from dba_objects where object_name like 'IDL%';OBJECT_NAME            OBJECT_TYPE------------------- ------------------IDL_CHAR$                 TABLEIDL_SB4$                  TABLEIDL_UB1$                  TABLEIDL_UB2$                  TABLE

ORA-00600: internal error code, arguments: [17069],[0xC0000000DDDFA690], [], [], [], [], [], []

IDL_UB1$ is one of four tables that hold compiled PL/SQL code:IDL_UB1$IDL_CHAR$IDL_UB2$IDL_SB4$"PL/SQL is based on the PRogramming language Ada. As a result, PL/SQL uses avariant of Descriptive Intermediate Attributed Notation for Ada (DIANA), whichis a tree-structured intermediate language. It is defined using a meta-notationcalled Interface Definition Language (IDL). DIANA provides for communicationinternal to compilers and other tools."At compile time, PL/SQL source code is translated into machine-readablem-code.Both the DIANA and m-code for a procedure or package are stored in thedatabase.At run time, they are loaded into the shared (memory) pool. The DIANA isused to compile dependent procedures; the m-code is simply executed."These four tables hold the DIANA and the so-code m-code. I think "m-code" isshort for machine-dependent byte code but there is a sizable machine-indenpendent partas well. If you have a look at sql.bsq, you can seethat Oracle documents the "type" column of these tables as follows:part number not null,/* part: 0 = diana, 1 = portable pcode, 2 = machine-dependentpcode */