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From: Gambhir Singh <gambhir.singh05@gmail.com>
Date: Wed, 7 May 2025 16:45:17 +0530
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 <CAHOGQfWk-xb3q0QSXY=xUsMohChEEZwjxoTzrFUK+D_GEcO+uw@mail.gmail.com>
Subject: Update command causing lock in DB.
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Hi,

Application team was executing UPDATE statement in DB through Abinitio
graph. When they trigger a job, a session is spawned in DB, in parallel
another session is also spawned and executed the same UPDATE statement.

When I checked the locks in DB, I found that both the sessions are updating
the same record. My concern is how UPDATE causes locking in DB.

Here is how MVCC works. If one session is updating a record, it should
release the lock once it updated the row and other one should be able to
acquire the row lock. Maybe I am wrong, please suggest how to handle this
situation.

-- 
Thanks & Regards
Gambhir Singh

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<div dir=3D"ltr"><div dir=3D"ltr"><div dir=3D"ltr"><div>Hi,<br clear=3D"all=
"></div><div><br></div><div><div class=3D"gmail_default" style=3D"font-fami=
ly:tahoma,sans-serif;font-size:small;color:rgb(0,0,0)"><span style=3D"font-=
family:Arial,Helvetica,sans-serif;color:rgb(34,34,34)">Application team was=
 executing UPDATE statement in DB through Abinitio graph. When they trigger=
 a job, a session is spawned in DB, in parallel another session is also spa=
wned and executed the same UPDATE statement.</span></div><br>When I checked=
 the locks in DB, I found that both the sessions are updating the same reco=
rd. My concern is how UPDATE causes locking in DB.<br><br>Here is how MVCC =
works. If one session is updating a record, it should release the lock once=
 it updated the row and other one should be able to acquire the row lock. M=
aybe I am wrong, please suggest how to handle this situation.<br></div><div=
><br></div><span class=3D"gmail_signature_prefix">-- </span><br><div dir=3D=
"ltr" class=3D"gmail_signature" data-smartmail=3D"gmail_signature"><div dir=
=3D"ltr">Thanks &amp; Regards<br>Gambhir Singh<br><br></div></div></div>
</div>
</div>

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