create or alter procedure p0(n integer)
as
    declare v integer;
begin
    if (n = 0) then
        select first 1 1 from mon$statements into v;
    else
        execute procedure p0(n - 1);
end!

create or alter procedure p1
as
begin
    execute procedure p0(2);
end!

commit!

execute procedure p1!

select * from mon$statements!
select * from mon$compiled_statements!
select * from mon$call_stack!

     MON$STATEMENT_ID     MON$ATTACHMENT_ID    MON$TRANSACTION_ID MON$STATE                                             MON$TIMESTAMP      MON$SQL_TEXT  MON$STAT_ID MON$EXPLAINED_PLAN MON$STATEMENT_TIMEOUT                                       MON$STATEMENT_TIMER MON$COMPILED_STATEMENT_ID 
===================== ===================== ===================== ========= ========================================================= ================= ============ ================== ===================== ========================================================= ========================= 
                   39                     3                     6         1 2021-11-24 11:35:56.5030 America/Sao_Paulo                              0:3           66             <null>                     0                                                    <null>                        39 
==============================================================================
MON$SQL_TEXT:  
execute procedure p1
==============================================================================

MON$COMPILED_STATEMENT_ID      MON$SQL_TEXT MON$EXPLAINED_PLAN MON$OBJECT_NAME                                                 MON$OBJECT_TYPE MON$PACKAGE_NAME                                                
========================= ================= ================== =============================================================== =============== =============================================================== 
                       39               0:1             <null> <null>                                                                   <null> <null>                                                          
==============================================================================
MON$SQL_TEXT:  
execute procedure p1
==============================================================================
                       41            <null>                0:2 P0                                                                            5 <null>                                                          
==============================================================================
MON$EXPLAINED_PLAN:  

Select Expression
    -> Singularity Check
        -> First N Records
            -> Table "MON$STATEMENTS" Full Scan
==============================================================================
                       40            <null>             <null> P1                                                                            5 <null>                                                          

          MON$CALL_ID      MON$STATEMENT_ID         MON$CALLER_ID MON$OBJECT_NAME                                                 MON$OBJECT_TYPE                                             MON$TIMESTAMP MON$SOURCE_LINE MON$SOURCE_COLUMN  MON$STAT_ID MON$PACKAGE_NAME                                                MON$COMPILED_STATEMENT_ID 
===================== ===================== ===================== =============================================================== =============== ========================================================= =============== ================= ============ =============================================================== ========================= 
                   43                    39                    42 P0                                                                            5 2021-11-24 11:35:56.5030 America/Sao_Paulo                              6                 9           54 <null>                                                                                 41 
                   42                    39                    41 P0                                                                            5 2021-11-24 11:35:56.5030 America/Sao_Paulo                              8                 9           57 <null>                                                                                 41 
                   41                    39                    40 P0                                                                            5 2021-11-24 11:35:56.5030 America/Sao_Paulo                              8                 9           60 <null>                                                                                 41 
                   40                    39                <null> P1                                                                            5 2021-11-24 11:35:56.5030 America/Sao_Paulo                              4                 5           63 <null>                                                                                 40