Description:
------------
I found problem in PDO_OCI, if Oracle session killed by ALTER SYSTEM KILL 
SESSION operator, PDO_OCI can't resume session.

For example we can find all PHP active sessions on Oracle:

SELECT
'ALTER SYSTEM KILL SESSION ''' || s.sid||','|| s.serial#||''' IMMEDIATE;'
FROM   gv$session s
      JOIN gv$process p ON p.addr = s.paddr AND p.inst_id = s.inst_id WHERE  
s.type != 'BACKGROUND'and s.program like 'php-fpm: pool%';

And run results strings for kill session:

ALTER SYSTEM KILL SESSION 'xxxx,xxx' IMMEDIATE; ALTER SYSTEM KILL SESSION 
'xxxx,xxx' IMMEDIATE;

First error that catch PHP script look so:

SQLSTATE[01002]: Disconnect error: 3113 OCIStmtExecute: Error while trying to 
retrieve text for error ORA-03113 separator not found in message(3144)separator 
not found in message(3142)
(/root/rpmbuild/BUILD/php-5.3.8/ext/pdo_oci/oci_statement.c:148)

Second and all next error look so:

SQLSTATE[HY000]: General error: 3114 OCIStmtExecute: Error while trying to 
retrieve text for error ORA-03114
(/root/rpmbuild/BUILD/php-5.3.8/ext/pdo_oci/oci_statement.c:148)

My connection parameters:
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION PDO::ATTR_PERSISTENT => true 
PDO::ATTR_AUTOCOMMIT => false