You cannot connect as SYSOPER, SYSDG, SYSKM, SYSBACKUP directly on the DB server if connect descriptor links to IPC protocol of the LISTENER. TNS: permission denied is raised.

Partition range could be INVALID in plan if not existed partition is going to be queried

NFS IPv6 seems to be working badly for Clusterware and database. 12.1.0.2 . 10 minutes timeouts and unnecessary semaphore waitings

In order to fix/revert HOME permission you can use rootcrs.sh or roots.sh with -init option. Or they can be altered manually by info from crsconfig_fileperms and crsconfig_dirs.

When dealing with GI and role separation, default owner for /Dev/oracleasm should be grid:asmadmin. Otherwise - ora-15183 raised

When computing huge pages for SGA and Clusterware is running on the top, please also include MGMT DB size into calculation, otherwise startup db might fail if use_large_pages = only

After link/fresh installation if ASM is used for DB files verify owner of Oracle binary. It should be Oracle:asmadmin. Otherwise - ORA-15183 (Asmlib initialization) might raise. Please see 1166697.1 for reference.

When attach database to new home dumping Opatch information might be misplaced. Solution described in 2190476.1.

When DBWRs are flushing changed blocks to disks during standby recovery your IO is the mostly impacted with significant writes.

If standby / redo log file cannot be read and should be deleted from the controlfile entries two steps is required 1) ALTER DATABASE CLEAR UNARCHIVED LOGFILE. This will set status of the file to UNASSIGNED 2) ALTER DATABASE DROP LOGFILE. This will remove entries from control

Just discovered a new favourite (hidden) parameter though it's been around since 11.2.0.x: _enqueue_paranoia_mode_enabled default FALSE

A recent comment on my blog (jonathanlewis.wordpress.com/2018/01/15/his…) suggests that you might still need to fake the occasional histogram even in the latest version of Oracle: jonathanlewis.wordpress.com/2018/10/15/fak…

Easily forgotten - dbms_log appered in 11g as the "public" face of dbms_system procedures: ksdwrt, ksdddt, ksdfls, ksdind. jonathanlewis.wordpress.com/2018/10/12/dbm…

The level of instrumentation of Oracle is awesome. You can get a line for a specific system call (like I/O), and with time, args (file, offset, size), and call stack. Kind of stace -k but from the application itself.

If standby database instance open with read only, AUDIT_TRAIL will change to OS instead of DB

Be careful about scripts that try to estimate unused space in a table - they may not cater for anything but the most basic definition. Here's a warning from a few years back: jonathanlewis.wordpress.com/2015/01/16/spa…

Marvelous Doc ID 2590172.1: "Remove the PDB-level SHARED_POOL_SIZE and/or SGA_MIN_SIZE initialization parameters. The only SGA memory sizing parameter that Oracle recommends setting at the PDB level is SGA_TARGET." Question is why it's not in the docs.oracle.com?

My thoughts on Tucker Carlson interviewing Putin — CNN was NOT ready for this:

A golden oldie - 2012 - that is still relevant to Oracle 19.3: "ANSI" outer joins doing using table scans when index fast full scan should suffice: jonathanlewis.wordpress.com/2012/07/16/ans…