Drop a tablespace in a PDB with a Guaranteed Restore Point being active

This was an interesting question I received from Alain Fuhrer a couple of weeks ago: “Why can’t I drop a tablespace in a PDB whit a Guaranteed Restore Point being active?”. It’s important to note that the GRP is not active in the same but in another PDB. An SR resolved the issue. But in case you face the same situation, here’s the solution. Drop a tablespace in a PDB with a Guaranteed Restore Point being active Simple test scenario. These are my PDBs: show pdbs CON_ID CON_NAME OPEN MODE RESTRICTED ———- —————————— ———- ———- 2 PDB$SEED READ ONLY NO…

Remove Underscore Parameters not only before you upgrade

Underscore parameters are a wonderful thing in Oracle. They are treated like a secret. But you can view them of course. Everybody can. Make a guess how many underscore parameters exist in Oracle 12.2.0.1.0. You’ll find the answer at the end of this blog post. But why should you remove underscore parameters not only before you upgrade? I’d like to explain below why underscores, especially too many of them, may cause a lot of trouble. Therefore, housekeeping is very important. Remove Underscore Parameters not only before you upgrade This is from a recent upgrade from Oracle 12.1.0.2 to Oracle 12.2.0.1…

Why EXCLUDE_SEED_CDB_VIEW is now an underscore in Oracle 12.2

I have received several questions from customers in the past weeks using Oracle Multitenant about the parameter exclude_seed_cdb_view.It magically disappeared and morphed into¬†_exclude_seed_cdb_view since Oracle Database 12.2.0.1. To be fair, the¬†exclude_seed_cdb_view is listed in the list of obsolete parameters in Oracle Database 12.2.0.1. What is EXCLUDE_SEED_CDB_VIEW? This parameter hides everything belonging to the PDB$SEED from the usual queries. For instance you ran a query against CDB_DATA_FILES but you won’t see the data files belonging to PDB$SEED in the result set. Whether this is good or bad, at least RMAN (Recovery Manager) worked always correctly. But I’m not a big fan…

Where do these large trace files come from in Oracle 12c?

Just had an observation about very large trace files on one of my customers I’m working with at the moment. When I write “very” I mean “VERY” as some grew over 10GB within a few hours. The files contained a ton of such messages: —– Cursor Obsoletion Dump sql_id=5p8a9d4017bq3 —– Parent cursor obsoleted 1 time(s). maxchild=1024 basephd=00007FFB8AD45CB0 phd=00007FFB8AD45CB0 After doing a bit of research I came across this document and an explanation: MOS Note:1955319.1; Huge Trace Files Created Containing “—– Cursor Obsoletion Dump sql_id=%s —–“ Well, we introduced an Enhancement – via an unpublished bug (and I’d guess it is…