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How does the read committed snapshot isolation level relate (link) the row in tempdb to the original row?

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esther last edited by

I understand that the read committed snapshot isolation level holds the row versions in the tempdb.

I enabled this feature on a test database and I was expecting to see a new column (guid) get automatically added to the source data table (which I thought SQL will use to link to the record in tempdb). But there is no such column I can visibly see.

How does the read committed snapshot isolation level relate (link) the row in tempdb to the original row?
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Avante last edited by
SQL Server adds this 14 byte overhead as internal information. You need to use special command to see the overhead, as noted by MBuschi.

Note that the overhead is not added until you modify a row, after you turned on RCSI.

These 14 bytes is a combo of two pieces of information:
1. XSN (Transaction Sequence Number), which identifies the transaction that performed the modification. This is 6 bytes.
2. RID, a pointer to the versioned row. This is 8 bytes.
https://docs.microsoft.com/en-us/sql/relational-databases/sql-server-transaction-locking-and-row-versioning-guide#space-used-in-data-rows
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Apparently the base isn't chosen.The error report is likely to indicate that the Abonents table has not been found in the current database (master, most likely).
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SQL Server native backups are not available on Azure SQL. Here you have automated backups with a retention period of up to 35 days or you have long-term backups that you can restore. If you do not want to use long term backups, you can export your databases as bacpac to Azure BLOB storage and import that bacpac at any time you want. You can also export your database to a local on-premises storage. Additionally you can create a copy of your databases, remove existing databases when you want, and rename the copy database as you wish.

How does the read committed snapshot isolation level relate (link) the row in tempdb to the original row?

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