Oracle Database Locks and How to check locks | Oracle Deadlocks

What is a database lock in the context of #SQL? ... When #data is locked, then that means that another #database session can NOT update that data until the lock is released (which unlocks the data and allows other database users to update that data. Locks are usually released by either a #ROLLBACK or #COMMIT SQL statement.
00:00 Database ACID Properties
04:05 Locks
04:12 Scenario of starting locks examples-1
20:51 Scenario of starting locks Examples-2
29:58 Scenario of starting locks LAB
46:16 Row level locks and Table level locks
52:49 Identify Blockers and Waiters inside the database
54:18 Find Locked Table Inside Oracle
55:28 Find blocked session
01:00:11 Find Lock wait time
01:02:02 Find blocked SQL
01:03:32 Find locked table
01:12:14 Resolving locks in Oracle
01:17:39 Database blocked Session Report
01:18:32 Why locks are not bad inside the database?
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[@rakeeshmukkera7593]

Hi arun, I really enjoyed n understand with this LOCKS session. Thanks

[@dbagenesis]

Glad it helped

[@ganeshsonwane2637]

this session was amazing.

[@dbagenesis]

Thank you!

[@NicolaeCristian175]

great tutorial! thank you

[@dbagenesis]

Glad you enjoyed it!

[@parasharampakhari1583]

Hii
I really injoy this session and it's wonderful session to understand blocking and waiting session in Oracle database

[@dbagenesis]

Thank you! Keep watching.

[@bhuvaneshwarisekar8390]

Amazing explanation ❤️❤️such a helpful video😊

[@dbagenesis]

Glad it was helpful!

[@prasadreddysunkari]

Nice explanation sir

[@dbagenesis]

Thank you!

[@Rasenganist]

Hello, thank you for the video, really nice talk and debug informations!
My question is:
- Does the ORA-00060 event an Oracle "tool" designed to autommaticcaly perform commit or rollback when a lock is detected?
We experience currently some very rare deadlocks for "insert" statement wich trace files shows that Oracle does a rollback. Yet I have to re-check the logs to see which session is rolled-back.

[@dbagenesis]

Oracle will rollback your transactions post detection of deadlock.

[@edim252525]

Thanks for the video, Is there a way to generate a report for locks that occur in the past?

[@dbagenesis]

Locks are something you can check while they are occur right at the moment. Once they are released, its hard to track until you have a script in place that constantly captures locks and stores in a table.
www.support.dbagenesis.com/post/lock-conflict-in-oracle

[@rajkishore1960]

🤘😝🤘 super fantastic great 👏😊

[@dbagenesis]

Thanks ✌️

[@avijitsharma5050]

Hi, i have been asked one question in interview.
There is a table in production with huge records & someone issued some kind of command, that locked the table. I need to find out some way that data is available to users. Now since data is huge, copying data into new table is not a good approach.
PS : i asked that lock will not create any issue while reading, since its write lock only. Interviewer said, assume its both read write lock.
What should I be doing in this case ??

[@dbagenesis]

There is nothing called as read-write lock, the interviewer was checking your knowledge. Here are the lock types on Oracle:
- Exclusive
- Shared
- Shared row exclusive
- Row exclusive
- Row shared

[@mattareddyyarasani5040]

I have seen one of the wait event with SYS user for long time with '0' hash value.is it considerable?

[@dbagenesis]

Depends, whats the wait event NAME?

[@mattareddyyarasani5040]

Class slave wait

[@geofreybiddier8640]

I just watched the video and developed interest. Can somebody help me with the website address.

[@ratanwaghmare341]

how to resolve enq-MS-contention,tx-row locck contention?

[@dbagenesis]

check this out: www.dba-oracle.com/t_enq_tx_row_lock_contention.htm#:~:text=Answer%3A%20The%20%22enq%3A%20TX,update%20the%20same%20data%20blocks.