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SanjayGuntur-2923 avatar image
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SanjayGuntur-2923 asked SanjayGuntur-2923 commented

A system assertion check has failed [Failed Assertion = 'IS_OFF(LSN_SLOT_MASK, log_prevPageLsn.m_slotId)']

We have been building and testing our application against SQL Server 2016. Recently, we wanted to upgrade our build/test environment to SQL 2019, so that we can recommend an upgrade to our customers.

Since we had many databases, i stopped sql server service, copied over the data files to new disks, and attached the database on a new virtual machine running SQL 2019 Developer edition (RTM). There were no errors attaching the database and everything looked good. But then we started seeing random SQL assertion failures when running our unit tests. The failures are not consistent, but when it happens, it always happens in a select few unit tests.

This is the info in the event log:

Index : 56160
EntryType : Error
InstanceId : 3221242538
Message : SQL Server Assertion: File: <"sql\\ntdbms\\storeng\\logrec\\pagelog.cpp">, line=180 Failed Assertion = 'IS_OFF(LSN_SLOT_MASK, log_prevPageLsn.m_slotId)'. This error may be timing-related. If the error persists after rerunning the
statement, use DBCC CHECKDB to check the database for structural integrity, or restart the server to ensure in-memory data structures are not corrupted.
Category : Server
CategoryNumber : 2
ReplacementStrings : {"sql\\ntdbms\\storeng\\logrec\\pagelog.cpp", 180, IS_OFF(LSN_SLOT_MASK, log_prevPageLsn.m_slotId)}
Source : MSSQLSERVER
TimeGenerated : 5/6/2021 7:15:38 PM
TimeWritten : 5/6/2021 7:15:38 PM
UserName :

I see the same error when trying to shrink the database as well. I had to rollback the environment as i could not figure out what was wrong or how to fix it. Would appreciate any help or advise.

sql-server-general
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Did you use DBCC CHECKDB to check the database for structural integrity?


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Yes, it did not report anything was wrong.

Edit: I just ran it again to make sure i did not miss anything, 'CHECKDB found 0 allocation errors and 0 consistency errors in database'

I have the SQLDump files, but can't seem to attach one of them here...

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1 Answer

ErlandSommarskog avatar image
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ErlandSommarskog answered SanjayGuntur-2923 commented

What is the output of "SELECT @@version"? You did apply Cumulative Update 10 when you installed SQL 2019, didn't you?

The error message is a token of a bug in SQL Server, and you would need to open a support case to get a fix. But first check that you have the most recent CU.

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Hi,

Thanks for the information and suggestion, I will proceed with creating a support ticket.

Initially, I worked with RTM. But while trying to find a resolution for this issue, I did apply CU 10, and the problem still persisted. I also saw CU 10 warned about a few access violations. My problem did not seem related, but since I had scripts to rebuild the machine, and to attach the databases,, so I went back to RTM.

'SELECT @@version' says 'Microsoft SQL Server 2019 (RTM) - 15.0.2000.5 (X64) Sep 24 2019 13:48:23 Copyright (C) 2019 Microsoft Corporation Developer Edition (64-bit) on Windows Server 2019 Datacenter 10.0 <X64> (Build 17763: ) (Hypervisor)'

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