Category Archives: Locking

ENABLE NOVALIDATE – Too Polite?

Oren Nakdimon Leave a Reply

Onine DDL operations are much more polite than offline DDL operations. They usually wait patiently for transactions that hold resources they need until these transactions end, and they do not block new DML statements. As I wrote in the past, adding a constraint as Enabled and Validated (which is the default for new constrtaints) is […]

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Excessive Locking when Dropping a Table

Oren Nakdimon Leave a Reply

I tried to drop a table today and failed due to “ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired”. That was weird because I knew that nobody had been using this table for months, and that the table had no enabled foreign keys. A quick investigation revealed the cause – the DROP […]

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