Compression Advisor killed my database!

Over the weekend one of the databases hung due to the flash recovery area was 100% full. I noticed one J001 process consuming significant CPU and I/O resources. Turns out this process was the automatic segment advisor job that runs on the weekend maintenance window.The SQL executed was something like:CREATE TABLE .dbms_tabcomp_temp_uncmpTABLESPACE NOLOGGINGASSELECT /*+ FULL(.)… Continue reading Compression Advisor killed my database!

Oracle Recursive Sessions ORA-00018

Today I want to talk about Oracle Database session usage; last week there was a problem with a database reporting ORA-00018: maximum number of sessions exceeded, but the number of sessions from v$session was much less than the one specified in SESSIONS parameter.So, what was going on?Turns out this is explained by internal recursive sessions… Continue reading Oracle Recursive Sessions ORA-00018