Search notes:

Oracle latch: cache buffers chains

Count the numbers of cache buffers chains and cache buffers lru chains latches:
select
   count(*) cnt,
   name
from
   v$latch_children
where
   name like 'cache buffers %'
group by
   name;
Check value of hidden parameter _db_block_hash_latches (Number of database block hash latches). It should correspond to count(*) of cache buffers chain:
select
   v.ksppstvl    value_v,
   v.ksppstdfl   default_value_v,
   w.ksppstvl    value_w,
   w.ksppstdfl   default_value_w
from
   x$ksppi  par                      join
   x$ksppcv v on par.indx = v.indx   join
   x$ksppsv w on par.indx = w.indx
where
   par.ksppinm = '_db_block_hash_latches';

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...', 1758206773, '216.73.216.150', 'Mozilla/5.0 App...', NULL) #2 /home/httpd/vhosts/renenyffenegger.ch/httpsdocs/notes/development/databases/Oracle/architecture/instance/SGA/latch/list/cache/buffers/chains(54): insert_webrequest() #3 {main} thrown in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php on line 78