Search notes:

oradebug dump systemstate

Dump systemstate with short callstacks (found in $ORACLE_HOME/rdmbs/admin/hangdiag.sql): 
oradebug dump systemstate 267
MOS Note 4523581.1 asys about systemstate levels:
258 is a fast alternative but we'd lose some lock element data
267 can be used if additional buffer cache / lock element data is needed with an understanding of the cost

See also

MOS Note 215858.1
oradebug doc event action systemstate

Index

Fatal error: Uncaught PDOException: SQLSTATE[HY000]: General error: 8 attempt to write a readonly database in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php:78 Stack trace: #0 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(78): PDOStatement->execute(Array) #1 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(30): insert_webrequest_('/notes/developm...', 1758206438, '216.73.216.150', 'Mozilla/5.0 App...', NULL) #2 /home/httpd/vhosts/renenyffenegger.ch/httpsdocs/notes/development/databases/Oracle/tools/oradebug/dump/systemstate/index(49): insert_webrequest() #3 {main} thrown in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php on line 78