sql - After process delete and abort deleting oracle working very slow -


i have database oracle 11g, after process delete , abort deleting process oracle working slow, restarted server several times did not help, see how can fix problem, please

over simplifying:

when aborted delete statement, oracle had done of work deleting of rows. while deleting rows oracle saving undo used multi-version concurrency control reading other transactions until 1 commits, , used in case of rollback.

when aborted delete oracle has apply undo put rows table, because delete statement atomic. either happened or nothing happened. applying undo relatively slow , going using resources until done. work not going go away restarting oracle, oracle apply undo until done.

next step investigate if resources being spent applying undo, or if slowness has cause. unfortunately can offer no in troubleshooting.

one quick way check rollback progress run query, wait minute, run again, , use estimate number of minutes until number shrinks zero. once rollback has started there no way stop or improve it. restarting server , killing processes won't speed up. have wait until number gets 0 , row disappears.

select used_urec gv$transaction;

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