Use BLOB instead of CLOB for JSON

Advice, I’ve met couple of times:

Oracle performance tip: JSON is always UTF8 -Use ‘al32utf8’ character set if possible
Use BLOB instead of CLOB CLOB stores data as UCS2/UTF16
Use lob data api to insert/fetch data - getBytes/setBytes instead of - getBlob/setBlob!

login.sql is not executed from SQLPATH

A lot has been written, that login.sql is no more executed from current folder, but if SQLPATH variable has been set in registry or in env variable and login.sql is not executed (but other scripts do) - patch from 2274608.1 have to be installed.
This is applicable to at least Oracle 12.2 clients

SQL json_object VS PL SQL json_object_t

Comparing performance for simple json generation in Oracle 12.2
SQL’s json_object performs 1.5 times faster.
Result

SQL json_object: 41
PL/SQL JSON_OBJECT_T: 64

Test case

DECLARE
   l_result CLOB;
  
   l_cnt NUMBER := 10000;
   l_start_time NUMBER;
   
   l_key VARCHAR2(100) := 'testkey';
   l_val VARCHAR2(32767) := lpad('x', 5000, 'x');
   
   FUNCTION simple_json(p_name IN VARCHAR2, p_value IN CLOB) RETURN CLOB IS
      l_result JSON_OBJECT_T := JSON_OBJECT_T;
   BEGIN
      l_result.put(p_name, p_value);
      RETURN l_result.to_clob;
   END;
BEGIN
   l_start_time := dbms_utility.get_time;
   FOR i IN 1 .. l_cnt LOOP
      l_val := lpad('x', 5000, 'x') || systimestamp;
      SELECT json_object(key l_key VALUE l_val RETURNING CLOB) json INTO l_result FROM dual;  
      --dbms_output.put_line(l_result);     
   END LOOP;
   dbms_output.put_line('SQL json_object: ' || (dbms_utility.get_time - l_start_time)); 

   l_start_time := dbms_utility.get_time;
   FOR i IN 1 .. l_cnt LOOP
      l_val := lpad('x', 5000, 'x') || systimestamp;
      l_result := simple_json(l_key, l_val);
      --dbms_output.put_line(l_result);     
   END LOOP;
   dbms_output.put_line('PL/SQL JSON_OBJECT_T: ' || (dbms_utility.get_time - l_start_time)); 
END;

Add domain user to ORA_DBA group

Right after Oracle 12c installation and database creation I was able to connect to the database with username and password

sqlplus sys/pass as sysdba
Connected to:
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production

but unable to connect with / as sysdba

sqlplus / as sysdba
ERROR:
ORA-01017: invalid username/password; logon denied

Connection from local administrator account worked perfectly without user name and password, so I’ve checked ORA_DBA group with lusrmgr.msc console and found that I have to add currently connected domain user to ORA_DBA group.
But Add user dialog doesn’t allow search and add domain users. Solution for this is command line under Local Administrator account

net localgroup ORA_DBA /add domain\USERNAME