Concurrent update on the same block

We all know that blocks are cached in buffer cache and there could only be one XCUR cache for each block. What will happen if multiple sessions are updating different rows in the same block simultaneously? SQL> drop table t1 purge; Table dropped. SQL> create table t1(id number, name varchar2(64)); Table created. SQL> begin 2… Continue reading Concurrent update on the same block

ORA-609 with TNS-12537

Question: Does it really mean cnnection was successfully established when you see the following information in listener.log: 12-OCT-2009 10:03:39 * (CONNECT_DATA=(SID=ORCL)) * (ADDRESS=(PROTOCOL=tcp)(HOST=123.456.1.123)(PORT=3158)) * establish * ORCL * 0 12-OCT-2009 10:03:39 * (CONNECT_DATA=(SID=ORCL)) * (ADDRESS=(PROTOCOL=tcp)(HOST=123.456.1.123)(PORT=3159)) * establish * ORCL * 0 Answer: NO!!!! As a big picture, these are the steps for a client connection:… Continue reading ORA-609 with TNS-12537